public async Task <LoRaDeviceRequestProcessResult> ProcessRequestAsync(LoRaRequest request, LoRaDevice loRaDevice)
{
var timeWatcher = request.GetTimeWatcher();
loRaDevice.EnsureConnected();
var loraPayload = (LoRaPayloadData)request.Payload;
var payloadFcnt = loraPayload.GetFcnt();
uint payloadFcntAdjusted = LoRaPayload.InferUpper32BitsForClientFcnt(payloadFcnt, loRaDevice.FCntUp);
Logger.Log(loRaDevice.DevEUI, $"converted 16bit FCnt {payloadFcnt} to 32bit FCnt {payloadFcntAdjusted}", LogLevel.Debug);
var payloadPort = loraPayload.GetFPort();
var requiresConfirmation = loraPayload.IsConfirmed || loraPayload.IsMacAnswerRequired;
LoRaADRResult loRaADRResult = null;
var frameCounterStrategy = this.frameCounterUpdateStrategyProvider.GetStrategy(loRaDevice.GatewayID);
if (frameCounterStrategy == null)
{
Logger.Log(loRaDevice.DevEUI, $"failed to resolve frame count update strategy, device gateway: {loRaDevice.GatewayID}, message ignored", LogLevel.Error);
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, LoRaDeviceRequestFailedReason.ApplicationError));
}
// Contains the Cloud to message we need to send
IReceivedLoRaCloudToDeviceMessage cloudToDeviceMessage = null;
// Leaf devices that restart lose the counter. In relax mode we accept the incoming frame counter
// ABP device does not reset the Fcnt so in relax mode we should reset for 0 (LMIC based) or 1
bool isFrameCounterFromNewlyStartedDevice = DetermineIfFramecounterIsFromNewlyStartedDevice(loRaDevice, payloadFcntAdjusted, frameCounterStrategy);
// Reply attack or confirmed reply
// Confirmed resubmit: A confirmed message that was received previously but we did not answer in time
// Device will send it again and we just need to return an ack (but also check for C2D to send it over)
if (!ValidateRequest(request, isFrameCounterFromNewlyStartedDevice, payloadFcntAdjusted, loRaDevice, requiresConfirmation, out bool isConfirmedResubmit, out LoRaDeviceRequestProcessResult result))
{
return(result);
}
var useMultipleGateways = string.IsNullOrEmpty(loRaDevice.GatewayID);
try
{
var bundlerResult = await this.TryUseBundler(request, loRaDevice, loraPayload, useMultipleGateways);
loRaADRResult = bundlerResult?.AdrResult;
if (bundlerResult?.PreferredGatewayResult != null)
{
this.HandlePreferredGatewayChanges(request, loRaDevice, bundlerResult);
}
// ADR should be performed before the deduplication
// as we still want to collect the signal info, even if we drop
// it in the next step
if (loRaADRResult == null && loraPayload.IsAdrEnabled)
{
loRaADRResult = await this.PerformADR(request, loRaDevice, loraPayload, payloadFcntAdjusted, loRaADRResult, frameCounterStrategy);
}
if (loRaADRResult?.CanConfirmToDevice == true || loraPayload.IsAdrReq)
{
// if we got an ADR result or request, we have to send the update to the device
requiresConfirmation = true;
}
if (useMultipleGateways)
{
// applying the correct deduplication
if (bundlerResult?.DeduplicationResult != null && !bundlerResult.DeduplicationResult.CanProcess)
{
// duplication strategy is indicating that we do not need to continue processing this message
Logger.Log(loRaDevice.DevEUI, $"duplication strategy indicated to not process message: ${payloadFcnt}", LogLevel.Debug);
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, LoRaDeviceRequestFailedReason.DeduplicationDrop));
}
}
else
{
// we must save class C devices regions in order to send c2d messages
if (loRaDevice.ClassType == LoRaDeviceClassType.C && request.Region.LoRaRegion != loRaDevice.LoRaRegion)
{
loRaDevice.UpdateRegion(request.Region.LoRaRegion, acceptChanges: false);
}
}
// if deduplication already processed the next framecounter down, use that
uint?fcntDown = loRaADRResult?.FCntDown > 0 ? loRaADRResult.FCntDown : bundlerResult?.NextFCntDown;
// If it is confirmed it require us to update the frame counter down
// Multiple gateways: in redis, otherwise in device twin
if (requiresConfirmation)
{
fcntDown = await this.EnsureHasFcntDownAsync(loRaDevice, fcntDown, payloadFcntAdjusted, frameCounterStrategy);
// Failed to update the fcnt down
// In multi gateway scenarios it means the another gateway was faster than using, can stop now
if (fcntDown <= 0)
{
Logger.Log(loRaDevice.DevEUI, "another gateway has already sent ack or downlink msg", LogLevel.Debug);
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, LoRaDeviceRequestFailedReason.HandledByAnotherGateway));
}
}
var validFcntUp = isFrameCounterFromNewlyStartedDevice || (payloadFcntAdjusted > loRaDevice.FCntUp);
if (validFcntUp || isConfirmedResubmit)
{
if (!isConfirmedResubmit)
{
Logger.Log(loRaDevice.DevEUI, $"valid frame counter, msg: {payloadFcntAdjusted} server: {loRaDevice.FCntUp}", LogLevel.Debug);
}
object payloadData = null;
byte[] decryptedPayloadData = null;
if (loraPayload.Frmpayload.Length > 0)
{
try
{
decryptedPayloadData = loraPayload.GetDecryptedPayload(loRaDevice.AppSKey);
}
catch (Exception ex)
{
Logger.Log(loRaDevice.DevEUI, $"failed to decrypt message: {ex.Message}", LogLevel.Error);
}
}
if (payloadPort == LoRaFPort.MacCommand)
{
if (decryptedPayloadData?.Length > 0)
{
loraPayload.MacCommands = MacCommand.CreateMacCommandFromBytes(loRaDevice.DevEUI, decryptedPayloadData);
}
if (loraPayload.IsMacAnswerRequired)
{
fcntDown = await this.EnsureHasFcntDownAsync(loRaDevice, fcntDown, payloadFcntAdjusted, frameCounterStrategy);
if (!fcntDown.HasValue || fcntDown <= 0)
{
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, LoRaDeviceRequestFailedReason.HandledByAnotherGateway));
}
requiresConfirmation = true;
}
}
else
{
if (string.IsNullOrEmpty(loRaDevice.SensorDecoder))
{
Logger.Log(loRaDevice.DevEUI, $"no decoder set in device twin. port: {payloadPort}", LogLevel.Debug);
payloadData = new UndecodedPayload(decryptedPayloadData);
}
else
{
Logger.Log(loRaDevice.DevEUI, $"decoding with: {loRaDevice.SensorDecoder} port: {payloadPort}", LogLevel.Debug);
var decodePayloadResult = await this.payloadDecoder.DecodeMessageAsync(loRaDevice.DevEUI, decryptedPayloadData, payloadPort, loRaDevice.SensorDecoder);
payloadData = decodePayloadResult.GetDecodedPayload();
if (decodePayloadResult.CloudToDeviceMessage != null)
{
if (string.IsNullOrEmpty(decodePayloadResult.CloudToDeviceMessage.DevEUI) || string.Equals(loRaDevice.DevEUI, decodePayloadResult.CloudToDeviceMessage.DevEUI, StringComparison.InvariantCultureIgnoreCase))
{
// sending c2d to same device
cloudToDeviceMessage = decodePayloadResult.CloudToDeviceMessage;
fcntDown = await this.EnsureHasFcntDownAsync(loRaDevice, fcntDown, payloadFcntAdjusted, frameCounterStrategy);
if (!fcntDown.HasValue || fcntDown <= 0)
{
// We did not get a valid frame count down, therefore we should not process the message
_ = cloudToDeviceMessage.AbandonAsync();
cloudToDeviceMessage = null;
}
else
{
requiresConfirmation = true;
}
}
else
{
this.SendClassCDeviceMessage(decodePayloadResult.CloudToDeviceMessage);
}
}
}
}
if (!isConfirmedResubmit)
{
// In case it is a Mac Command only we don't want to send it to the IoT Hub
if (payloadPort != LoRaFPort.MacCommand)
{
if (!await this.SendDeviceEventAsync(request, loRaDevice, timeWatcher, payloadData, bundlerResult?.DeduplicationResult, decryptedPayloadData))
{
// failed to send event to IoT Hub, stop now
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, LoRaDeviceRequestFailedReason.IoTHubProblem));
}
}
loRaDevice.SetFcntUp(payloadFcntAdjusted);
}
}
// We check if we have time to futher progress or not
// C2D checks are quite expensive so if we are really late we just stop here
var timeToSecondWindow = timeWatcher.GetRemainingTimeToReceiveSecondWindow(loRaDevice);
if (timeToSecondWindow < LoRaOperationTimeWatcher.ExpectedTimeToPackageAndSendMessage)
{
if (requiresConfirmation)
{
Logger.Log(loRaDevice.DevEUI, $"too late for down message ({timeWatcher.GetElapsedTime()})", LogLevel.Information);
}
return(new LoRaDeviceRequestProcessResult(loRaDevice, request));
}
// If it is confirmed and
// - Downlink is disabled for the device or
// - we don't have time to check c2d and send to device we return now
if (requiresConfirmation && (!loRaDevice.DownlinkEnabled || timeToSecondWindow.Subtract(LoRaOperationTimeWatcher.ExpectedTimeToPackageAndSendMessage) <= LoRaOperationTimeWatcher.MinimumAvailableTimeToCheckForCloudMessage))
{
var downlinkMessageBuilderResp = DownlinkMessageBuilder.CreateDownlinkMessage(
this.configuration,
loRaDevice,
request,
timeWatcher,
cloudToDeviceMessage,
false, // fpending
fcntDown.GetValueOrDefault(),
loRaADRResult);
if (downlinkMessageBuilderResp.DownlinkPktFwdMessage != null)
{
_ = request.PacketForwarder.SendDownstreamAsync(downlinkMessageBuilderResp.DownlinkPktFwdMessage);
if (cloudToDeviceMessage != null)
{
if (downlinkMessageBuilderResp.IsMessageTooLong)
{
await cloudToDeviceMessage.AbandonAsync();
}
else
{
await cloudToDeviceMessage.CompleteAsync();
}
}
}
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, downlinkMessageBuilderResp.DownlinkPktFwdMessage));
}
// Flag indicating if there is another C2D message waiting
var fpending = false;
// If downlink is enabled and we did not get a cloud to device message from decoder
// try to get one from IoT Hub C2D
if (loRaDevice.DownlinkEnabled && cloudToDeviceMessage == null)
{
// ReceiveAsync has a longer timeout
// But we wait less that the timeout (available time before 2nd window)
// if message is received after timeout, keep it in loraDeviceInfo and return the next call
var timeAvailableToCheckCloudToDeviceMessages = timeWatcher.GetAvailableTimeToCheckCloudToDeviceMessage(loRaDevice);
if (timeAvailableToCheckCloudToDeviceMessages >= LoRaOperationTimeWatcher.MinimumAvailableTimeToCheckForCloudMessage)
{
cloudToDeviceMessage = await this.ReceiveCloudToDeviceAsync(loRaDevice, timeAvailableToCheckCloudToDeviceMessages);
if (cloudToDeviceMessage != null && !this.ValidateCloudToDeviceMessage(loRaDevice, request, cloudToDeviceMessage))
{
// Reject cloud to device message based on result from ValidateCloudToDeviceMessage
_ = cloudToDeviceMessage.RejectAsync();
cloudToDeviceMessage = null;
}
if (cloudToDeviceMessage != null)
{
if (!requiresConfirmation)
{
// The message coming from the device was not confirmed, therefore we did not computed the frame count down
// Now we need to increment because there is a C2D message to be sent
fcntDown = await this.EnsureHasFcntDownAsync(loRaDevice, fcntDown, payloadFcntAdjusted, frameCounterStrategy);
if (!fcntDown.HasValue || fcntDown <= 0)
{
// We did not get a valid frame count down, therefore we should not process the message
_ = cloudToDeviceMessage.AbandonAsync();
cloudToDeviceMessage = null;
}
else
{
requiresConfirmation = true;
}
}
// Checking again if cloudToDeviceMessage is valid because the fcntDown resolution could have failed,
// causing us to drop the message
if (cloudToDeviceMessage != null)
{
var remainingTimeForFPendingCheck = timeWatcher.GetRemainingTimeToReceiveSecondWindow(loRaDevice) - (LoRaOperationTimeWatcher.CheckForCloudMessageCallEstimatedOverhead + LoRaOperationTimeWatcher.MinimumAvailableTimeToCheckForCloudMessage);
if (remainingTimeForFPendingCheck >= LoRaOperationTimeWatcher.MinimumAvailableTimeToCheckForCloudMessage)
{
var additionalMsg = await this.ReceiveCloudToDeviceAsync(loRaDevice, LoRaOperationTimeWatcher.MinimumAvailableTimeToCheckForCloudMessage);
if (additionalMsg != null)
{
fpending = true;
Logger.Log(loRaDevice.DevEUI, $"found cloud to device message, setting fpending flag, message id: {additionalMsg.MessageId ?? "undefined"}", LogLevel.Information);
_ = additionalMsg.AbandonAsync();
}
}
}
}
}
}
// No C2D message and request was not confirmed, return nothing
if (!requiresConfirmation)
{
return(new LoRaDeviceRequestProcessResult(loRaDevice, request));
}
var confirmDownlinkMessageBuilderResp = DownlinkMessageBuilder.CreateDownlinkMessage(
this.configuration,
loRaDevice,
request,
timeWatcher,
cloudToDeviceMessage,
fpending,
fcntDown.GetValueOrDefault(),
loRaADRResult);
if (cloudToDeviceMessage != null)
{
if (confirmDownlinkMessageBuilderResp.DownlinkPktFwdMessage == null)
{
Logger.Log(loRaDevice.DevEUI, $"out of time for downstream message, will abandon cloud to device message id: {cloudToDeviceMessage.MessageId ?? "undefined"}", LogLevel.Information);
_ = cloudToDeviceMessage.AbandonAsync();
}
else if (confirmDownlinkMessageBuilderResp.IsMessageTooLong)
{
Logger.Log(loRaDevice.DevEUI, $"payload will not fit in current receive window, will abandon cloud to device message id: {cloudToDeviceMessage.MessageId ?? "undefined"}", LogLevel.Error);
_ = cloudToDeviceMessage.AbandonAsync();
}
else
{
_ = cloudToDeviceMessage.CompleteAsync();
}
}
if (confirmDownlinkMessageBuilderResp.DownlinkPktFwdMessage != null)
{
_ = request.PacketForwarder.SendDownstreamAsync(confirmDownlinkMessageBuilderResp.DownlinkPktFwdMessage);
}
return(new LoRaDeviceRequestProcessResult(loRaDevice, request, confirmDownlinkMessageBuilderResp.DownlinkPktFwdMessage));
}
finally
{
try
{
await loRaDevice.SaveChangesAsync();
}
catch (Exception saveChangesException)
{
Logger.Log(loRaDevice.DevEUI, $"error updating reported properties. {saveChangesException.Message}", LogLevel.Error);
}
}
}
