示例#1
0
        public LoRaDeviceTelemetry(Rxpk rxpk, LoRaPayloadData loRaPayloadData, object payloadData)
        {
            if (rxpk.ExtraData != null)
            {
                this.ExtraData = new Dictionary <string, object>(rxpk.ExtraData);
            }

            this.Chan    = rxpk.Chan;
            this.Codr    = rxpk.Codr;
            this.Data    = payloadData;
            this.Rawdata = rxpk.Data;
            this.Datr    = rxpk.Datr;
            this.Freq    = rxpk.Freq;
            this.Lsnr    = rxpk.Lsnr;
            this.Modu    = rxpk.Modu;
            this.Rfch    = rxpk.Rfch;
            this.Rssi    = rxpk.Rssi;
            this.Size    = rxpk.Size;
            this.Stat    = rxpk.Stat;
            this.Time    = rxpk.Time;
            this.Tmms    = rxpk.Tmms;
            this.Tmst    = rxpk.Tmst;
            this.Fcnt    = loRaPayloadData.GetFcnt();
            this.Port    = loRaPayloadData.GetFPort();
        }
示例#2
0
        public LoRaDeviceTelemetry(Rxpk rxpk, LoRaPayloadData upstreamPayload, object payloadData, byte[] decryptedPayloadData)
        {
            if (rxpk.ExtraData != null)
            {
                this.ExtraData = new Dictionary <string, object>(rxpk.ExtraData);
            }

            this.Chan    = rxpk.Chan;
            this.Codr    = rxpk.Codr;
            this.Data    = payloadData;
            this.Rawdata = decryptedPayloadData?.Length > 0 ? Convert.ToBase64String(decryptedPayloadData) : string.Empty;
            this.Datr    = rxpk.Datr;
            this.Freq    = rxpk.Freq;
            this.Lsnr    = rxpk.Lsnr;
            this.Modu    = rxpk.Modu;
            this.Rfch    = rxpk.Rfch;
            this.Rssi    = rxpk.Rssi;
            this.Size    = rxpk.Size;
            this.Stat    = rxpk.Stat;
            this.Time    = rxpk.Time;
            this.Tmms    = rxpk.Tmms;
            this.Tmst    = rxpk.Tmst;
            this.Fcnt    = upstreamPayload.GetFcnt();
            this.Port    = upstreamPayload.GetFPort();
        }
示例#3
0
        private void EnsureDownlinkIsCorrect(DownlinkPktFwdMessage downlink, SimulatedDevice simDevice, ReceivedLoRaCloudToDeviceMessage sentMessage)
        {
            Assert.NotNull(downlink);
            Assert.NotNull(downlink.Txpk);
            Assert.True(downlink.Txpk.Imme);
            Assert.Equal(0, downlink.Txpk.Tmst);
            Assert.NotEmpty(downlink.Txpk.Data);

            byte[] downstreamPayloadBytes = Convert.FromBase64String(downlink.Txpk.Data);
            var    downstreamPayload      = new LoRaPayloadData(downstreamPayloadBytes);

            Assert.Equal(sentMessage.Fport, downstreamPayload.GetFPort());
            Assert.Equal(downstreamPayload.DevAddr.ToArray(), ConversionHelper.StringToByteArray(simDevice.DevAddr));
            var decryptedPayload = downstreamPayload.GetDecryptedPayload(simDevice.AppSKey);

            Assert.Equal(sentMessage.Payload, Encoding.UTF8.GetString(decryptedPayload));
        }
        public async Task When_ABP_Sends_Upstream_Followed_By_DirectMethod_Should_Send_Upstream_And_Downstream(string deviceGatewayID, uint fcntDownFromTwin, uint fcntDelta)
        {
            const uint payloadFcnt = 2; // to avoid relax mode reset

            var simDevice = new SimulatedDevice(TestDeviceInfo.CreateABPDevice(1, gatewayID: deviceGatewayID, deviceClassType: 'c'), frmCntDown: fcntDownFromTwin);

            this.LoRaDeviceClient.Setup(x => x.UpdateReportedPropertiesAsync(It.IsNotNull <TwinCollection>()))
            .ReturnsAsync(true);

            var twin = simDevice.CreateABPTwin(reportedProperties: new Dictionary <string, object>
            {
                { TwinProperty.Region, LoRaRegionType.EU868.ToString() }
            });

            this.LoRaDeviceClient.Setup(x => x.GetTwinAsync())
            .ReturnsAsync(twin);

            this.LoRaDeviceClient.Setup(x => x.SendEventAsync(It.IsNotNull <LoRaDeviceTelemetry>(), null))
            .ReturnsAsync(true);

            this.LoRaDeviceClient.Setup(x => x.ReceiveAsync(It.IsNotNull <TimeSpan>()))
            .ReturnsAsync((Message)null);

            this.LoRaDeviceApi.Setup(x => x.SearchByDevAddrAsync(simDevice.DevAddr))
            .ReturnsAsync(new SearchDevicesResult(new IoTHubDeviceInfo(simDevice.DevAddr, simDevice.DevEUI, "123").AsList()));

            if (deviceGatewayID == null)
            {
                this.LoRaDeviceApi.Setup(x => x.ExecuteFunctionBundlerAsync(simDevice.DevEUI, It.IsNotNull <FunctionBundlerRequest>()))
                .ReturnsAsync(new FunctionBundlerResult());
            }

            var deviceRegistry = new LoRaDeviceRegistry(this.ServerConfiguration, this.NewMemoryCache(), this.LoRaDeviceApi.Object, this.LoRaDeviceFactory);

            var messageDispatcher = new MessageDispatcher(
                this.ServerConfiguration,
                deviceRegistry,
                this.FrameCounterUpdateStrategyProvider);

            var request = this.CreateWaitableRequest(simDevice.CreateUnconfirmedMessageUplink("1", fcnt: payloadFcnt).Rxpk[0]);

            messageDispatcher.DispatchRequest(request);
            Assert.True(await request.WaitCompleteAsync());
            Assert.True(request.ProcessingSucceeded);

            // wait until cache has been updated
            await Task.Delay(50);

            // Adds fcntdown to device, simulating multiple downstream calls
            Assert.True(deviceRegistry.InternalGetCachedDevicesForDevAddr(simDevice.DevAddr).TryGetValue(simDevice.DevEUI, out var loRaDevice));
            loRaDevice.SetFcntDown(fcntDelta + loRaDevice.FCntDown);

            var classCSender = new DefaultClassCDevicesMessageSender(
                this.ServerConfiguration,
                deviceRegistry,
                this.PacketForwarder,
                this.FrameCounterUpdateStrategyProvider);

            var c2d = new ReceivedLoRaCloudToDeviceMessage()
            {
                DevEUI    = simDevice.DevEUI,
                MessageId = Guid.NewGuid().ToString(),
                Payload   = "aaaa",
                Fport     = 18,
            };

            var expectedFcntDown = fcntDownFromTwin + Constants.MAX_FCNT_UNSAVED_DELTA + fcntDelta;

            if (string.IsNullOrEmpty(deviceGatewayID))
            {
                this.LoRaDeviceApi.Setup(x => x.NextFCntDownAsync(simDevice.DevEUI, fcntDownFromTwin + fcntDelta, 0, this.ServerConfiguration.GatewayID))
                .ReturnsAsync((ushort)expectedFcntDown);
            }

            Assert.True(await classCSender.SendAsync(c2d));
            Assert.Single(this.PacketForwarder.DownlinkMessages);
            var downstreamMsg = this.PacketForwarder.DownlinkMessages[0];

            byte[] downstreamPayloadBytes = Convert.FromBase64String(downstreamMsg.Txpk.Data);
            var    downstreamPayload      = new LoRaPayloadData(downstreamPayloadBytes);

            Assert.Equal(expectedFcntDown, downstreamPayload.GetFcnt());
            Assert.Equal(c2d.Fport, downstreamPayload.GetFPort());
            Assert.Equal(downstreamPayload.DevAddr.ToArray(), ConversionHelper.StringToByteArray(simDevice.DevAddr));
            var decryptedPayload = downstreamPayload.GetDecryptedPayload(simDevice.AppSKey);

            Assert.Equal(c2d.Payload, Encoding.UTF8.GetString(decryptedPayload));

            Assert.Equal(expectedFcntDown, loRaDevice.FCntDown);
            Assert.Equal(payloadFcnt, loRaDevice.FCntUp);

            Assert.False(loRaDevice.HasFrameCountChanges);

            this.LoRaDeviceApi.VerifyAll();
            this.LoRaDeviceClient.VerifyAll();
        }
        public async Task When_OTAA_Join_Then_Sends_Upstream_DirectMethod_Should_Send_Downstream(string deviceGatewayID)
        {
            var simDevice = new SimulatedDevice(TestDeviceInfo.CreateOTAADevice(1, deviceClassType: 'c', gatewayID: deviceGatewayID));

            this.LoRaDeviceClient.Setup(x => x.GetTwinAsync())
            .ReturnsAsync(simDevice.CreateOTAATwin());

            var savedAppSKey = string.Empty;
            var savedNwkSKey = string.Empty;
            var savedDevAddr = string.Empty;

            this.LoRaDeviceClient.Setup(x => x.UpdateReportedPropertiesAsync(It.IsNotNull <TwinCollection>()))
            .ReturnsAsync(true)
            .Callback <TwinCollection>((t) =>
            {
                savedAppSKey = t[TwinProperty.AppSKey];
                savedNwkSKey = t[TwinProperty.NwkSKey];
                savedDevAddr = t[TwinProperty.DevAddr];

                Assert.NotEmpty(savedAppSKey);
                Assert.NotEmpty(savedNwkSKey);
                Assert.NotEmpty(savedDevAddr);
            });

            this.LoRaDeviceClient.Setup(x => x.SendEventAsync(It.IsNotNull <LoRaDeviceTelemetry>(), null))
            .ReturnsAsync(true);

            this.LoRaDeviceClient.Setup(x => x.ReceiveAsync(It.IsNotNull <TimeSpan>()))
            .ReturnsAsync((Message)null);

            if (deviceGatewayID == null)
            {
                this.LoRaDeviceApi.Setup(x => x.ExecuteFunctionBundlerAsync(simDevice.DevEUI, It.IsNotNull <FunctionBundlerRequest>()))
                .ReturnsAsync(new FunctionBundlerResult());
            }

            this.LoRaDeviceApi.Setup(x => x.SearchAndLockForJoinAsync(this.ServerConfiguration.GatewayID, simDevice.DevEUI, simDevice.AppEUI, It.IsNotNull <string>()))
            .ReturnsAsync(new SearchDevicesResult(new IoTHubDeviceInfo(simDevice.DevAddr, simDevice.DevEUI, "123").AsList()));

            var deviceRegistry = new LoRaDeviceRegistry(this.ServerConfiguration, this.NewMemoryCache(), this.LoRaDeviceApi.Object, this.LoRaDeviceFactory);

            var messageDispatcher = new MessageDispatcher(
                this.ServerConfiguration,
                deviceRegistry,
                this.FrameCounterUpdateStrategyProvider);

            var joinRxpk    = simDevice.CreateJoinRequest().SerializeUplink(simDevice.AppKey).Rxpk[0];
            var joinRequest = this.CreateWaitableRequest(joinRxpk);

            messageDispatcher.DispatchRequest(joinRequest);
            Assert.True(await joinRequest.WaitCompleteAsync());
            Assert.True(joinRequest.ProcessingSucceeded);

            simDevice.SetupJoin(savedAppSKey, savedNwkSKey, savedDevAddr);
            var request = this.CreateWaitableRequest(simDevice.CreateUnconfirmedMessageUplink("1").Rxpk[0]);

            messageDispatcher.DispatchRequest(request);
            Assert.True(await request.WaitCompleteAsync());
            Assert.True(request.ProcessingSucceeded);

            var classCSender = new DefaultClassCDevicesMessageSender(
                this.ServerConfiguration,
                deviceRegistry,
                this.PacketForwarder,
                this.FrameCounterUpdateStrategyProvider);

            var c2d = new ReceivedLoRaCloudToDeviceMessage()
            {
                DevEUI    = simDevice.DevEUI,
                MessageId = Guid.NewGuid().ToString(),
                Payload   = "aaaa",
                Fport     = 14,
            };

            if (string.IsNullOrEmpty(deviceGatewayID))
            {
                this.LoRaDeviceApi.Setup(x => x.NextFCntDownAsync(simDevice.DevEUI, simDevice.FrmCntDown, 0, this.ServerConfiguration.GatewayID))
                .ReturnsAsync((ushort)(simDevice.FrmCntDown + 1));
            }

            Assert.True(await classCSender.SendAsync(c2d));
            Assert.Equal(2, this.PacketForwarder.DownlinkMessages.Count);
            var downstreamMsg = this.PacketForwarder.DownlinkMessages[1];

            TestLogger.Log($"appSKey: {simDevice.AppSKey}, nwkSKey: {simDevice.NwkSKey}");

            byte[] downstreamPayloadBytes = Convert.FromBase64String(downstreamMsg.Txpk.Data);
            var    downstreamPayload      = new LoRaPayloadData(downstreamPayloadBytes);

            Assert.Equal(1, downstreamPayload.GetFcnt());
            Assert.Equal(c2d.Fport, downstreamPayload.GetFPort());
            Assert.Equal(downstreamPayload.DevAddr.ToArray(), ConversionHelper.StringToByteArray(savedDevAddr));
            var decryptedPayload = downstreamPayload.GetDecryptedPayload(simDevice.AppSKey);

            Assert.Equal(c2d.Payload, Encoding.UTF8.GetString(decryptedPayload));

            this.LoRaDeviceApi.VerifyAll();
            this.LoRaDeviceClient.VerifyAll();
        }
示例#6
0
        public async Task Should_Reject(
            bool isConfirmed,
            bool hasMacInUpstream,
            bool hasMacInC2D,
            [CombinatorialValues("SF10BW125", "SF9BW125", "SF8BW125", "SF7BW125")] string datr)
        {
            const int InitialDeviceFcntUp   = 9;
            const int InitialDeviceFcntDown = 20;

            var simulatedDevice = new SimulatedDevice(
                TestDeviceInfo.CreateABPDevice(1, gatewayID: this.ServerConfiguration.GatewayID),
                frmCntUp: InitialDeviceFcntUp,
                frmCntDown: InitialDeviceFcntDown);

            var loraDevice = this.CreateLoRaDevice(simulatedDevice);

            Rxpk rxpk = this.CreateUpstreamRxpk(isConfirmed, hasMacInUpstream, datr, simulatedDevice);

            if (!hasMacInUpstream)
            {
                this.LoRaDeviceClient.Setup(x => x.SendEventAsync(It.IsNotNull <LoRaDeviceTelemetry>(), null))
                .ReturnsAsync(true);
            }

            var    euRegion                      = RegionManager.EU868;
            var    c2dMessageMacCommand          = new DevStatusRequest();
            var    c2dMessageMacCommandSize      = hasMacInC2D ? c2dMessageMacCommand.Length : 0;
            var    upstreamMessageMacCommandSize = 0;
            string expectedDownlinkDatr;

            if (hasMacInUpstream)
            {
                upstreamMessageMacCommandSize = new LinkCheckAnswer(1, 1).Length;
            }

            expectedDownlinkDatr = datr;

            var c2dPayloadSize = euRegion.GetMaxPayloadSize(expectedDownlinkDatr)
                                 - c2dMessageMacCommandSize
                                 + 1 // make message too long on purpose
                                 - Constants.LORA_PROTOCOL_OVERHEAD_SIZE;

            var c2dMessagePayload = TestUtils.GeneratePayload("123457890", (int)c2dPayloadSize);

            var c2dMessage = new ReceivedLoRaCloudToDeviceMessage()
            {
                Payload = c2dMessagePayload,
                Fport   = 1,
            };

            if (hasMacInC2D)
            {
                c2dMessage.MacCommands = new[] { c2dMessageMacCommand };
            }

            var cloudToDeviceMessage = c2dMessage.CreateMessage();

            this.LoRaDeviceClient.Setup(x => x.ReceiveAsync(It.IsAny <TimeSpan>()))
            .ReturnsAsync(cloudToDeviceMessage);

            this.LoRaDeviceClient.Setup(x => x.RejectAsync(cloudToDeviceMessage))
            .ReturnsAsync(true);

            var deviceRegistry = new LoRaDeviceRegistry(this.ServerConfiguration, this.NewNonEmptyCache(loraDevice), this.LoRaDeviceApi.Object, this.LoRaDeviceFactory);

            // Send to message processor
            var messageProcessor = new MessageDispatcher(
                this.ServerConfiguration,
                deviceRegistry,
                this.FrameCounterUpdateStrategyProvider);

            var request = this.CreateWaitableRequest(rxpk);

            messageProcessor.DispatchRequest(request);

            // Expectations
            // 1. Message was sent to IoT Hub
            Assert.True(await request.WaitCompleteAsync());
            Assert.True(request.ProcessingSucceeded);

            var shouldHaveADownlink = isConfirmed || hasMacInUpstream;

            // 2. Return is downstream message ONLY
            // if is confirmed or had Mac commands in upstream message
            if (shouldHaveADownlink)
            {
                Assert.NotNull(request.ResponseDownlink);
                Assert.Equal(expectedDownlinkDatr, request.ResponseDownlink.Txpk.Datr);

                var downlinkMessage = this.PacketForwarder.DownlinkMessages[0];
                var payloadDataDown = new LoRaPayloadData(Convert.FromBase64String(downlinkMessage.Txpk.Data));
                payloadDataDown.PerformEncryption(loraDevice.AppSKey);

                Assert.Equal(payloadDataDown.DevAddr.ToArray(), LoRaTools.Utils.ConversionHelper.StringToByteArray(loraDevice.DevAddr));
                Assert.Equal(LoRaMessageType.UnconfirmedDataDown, payloadDataDown.LoRaMessageType);

                if (hasMacInUpstream)
                {
                    Assert.Equal(new LinkCheckAnswer(1, 1).Length, payloadDataDown.Frmpayload.Length);
                    Assert.Equal(0, payloadDataDown.GetFPort());
                }
            }
            else
            {
                Assert.Null(request.ResponseDownlink);
            }

            this.LoRaDeviceClient.VerifyAll();
            this.LoRaDeviceApi.VerifyAll();
        }
示例#7
0
        public void When_Creating_Rxpk_Recreating_Payload_Should_Match_Source_Values(LoRaMessageType loRaMessageType, string data)
        {
            var devAddrText = "00000060";
            var appSKeyText = "00000060000000600000006000000060";
            var nwkSKeyText = "00000060000000600000006000000060";

            ushort fcnt = 12;

            byte[] devAddr = ConversionHelper.StringToByteArray(devAddrText);
            Array.Reverse(devAddr);
            byte[] fCtrl     = new byte[] { 0x80 };
            var    fcntBytes = BitConverter.GetBytes(fcnt);
            var    fopts     = new List <MacCommand>();

            byte[] fPort   = new byte[] { 1 };
            byte[] payload = Encoding.UTF8.GetBytes(data);
            Array.Reverse(payload);

            // 0 = uplink, 1 = downlink
            int direction         = 0;
            var devicePayloadData = new LoRaPayloadData(loRaMessageType, devAddr, fCtrl, fcntBytes, fopts, fPort, payload, direction);

            Assert.Equal(12, devicePayloadData.GetFcnt());
            Assert.Equal(0, devicePayloadData.Direction);
            Assert.Equal(1, devicePayloadData.GetFPort());

            var datr = "SF10BW125";
            var freq = 868.3;

            var uplinkMsg = devicePayloadData.SerializeUplink(appSKeyText, nwkSKeyText, datr, freq, 0);

            // Now try to recreate LoRaPayloadData from rxpk
            Assert.True(LoRaPayload.TryCreateLoRaPayload(uplinkMsg.Rxpk[0], out LoRaPayload parsedLoRaPayload));
            Assert.Equal(loRaMessageType, parsedLoRaPayload.LoRaMessageType);
            Assert.IsType <LoRaPayloadData>(parsedLoRaPayload);
            var parsedLoRaPayloadData = (LoRaPayloadData)parsedLoRaPayload;

            Assert.Equal(12, parsedLoRaPayloadData.GetFcnt());
            Assert.Equal(0, parsedLoRaPayloadData.Direction);
            Assert.Equal(1, parsedLoRaPayloadData.GetFPort());

            // Ensure that mic check and getting payload back works
            Assert.True(parsedLoRaPayloadData.CheckMic(nwkSKeyText)); // does not matter where the check mic happen, should always work!
            var parsedPayloadBytes = parsedLoRaPayloadData.GetDecryptedPayload(appSKeyText);

            Assert.Equal(data, Encoding.UTF8.GetString(parsedPayloadBytes));

            // checking mic and getting payload should not change the payload properties
            Assert.Equal(12, parsedLoRaPayloadData.GetFcnt());
            Assert.Equal(0, parsedLoRaPayloadData.Direction);
            Assert.Equal(1, parsedLoRaPayloadData.GetFPort());

            // checking mic should not break getting the payload
            Assert.True(parsedLoRaPayloadData.CheckMic(nwkSKeyText)); // does not matter where the check mic happen, should always work!
            var parsedPayloadBytes2 = parsedLoRaPayloadData.GetDecryptedPayload(appSKeyText);

            Assert.Equal(data, Encoding.UTF8.GetString(parsedPayloadBytes2));

            // checking mic and getting payload should not change the payload properties
            Assert.Equal(12, parsedLoRaPayloadData.GetFcnt());
            Assert.Equal(0, parsedLoRaPayloadData.Direction);
            Assert.Equal(1, parsedLoRaPayloadData.GetFPort());
        }
        /// <summary>
        /// Process LoRa message where the payload is of type LoRaPayloadData
        /// </summary>
        async Task <DownlinkPktFwdMessage> ProcessDataMessageAsync(LoRaTools.LoRaPhysical.Rxpk rxpk, LoRaPayloadData loraPayload, DateTime startTime)
        {
            var devAddr = loraPayload.DevAddr;

            var timeWatcher = new LoRaOperationTimeWatcher(this.loraRegion, startTime);

            using (var processLogger = new ProcessLogger(timeWatcher, devAddr))
            {
                if (!this.IsValidNetId(loraPayload.GetDevAddrNetID(), this.configuration.NetId))
                {
                    Logger.Log(ConversionHelper.ByteArrayToString(devAddr), "device is using another network id, ignoring this message", LogLevel.Debug);
                    processLogger.LogLevel = LogLevel.Debug;
                    return(null);
                }

                // Find device that matches:
                // - devAddr
                // - mic check (requires: loraDeviceInfo.NwkSKey or loraDeviceInfo.AppKey, rxpk.LoraPayload.Mic)
                // - gateway id
                var loRaDevice = await this.deviceRegistry.GetDeviceForPayloadAsync(loraPayload);

                if (loRaDevice == null)
                {
                    Logger.Log(ConversionHelper.ByteArrayToString(devAddr), $"device is not from our network, ignoring message", LogLevel.Information);
                    return(null);
                }

                // Add context to logger
                processLogger.SetDevEUI(loRaDevice.DevEUI);

                var isMultiGateway       = !string.Equals(loRaDevice.GatewayID, this.configuration.GatewayID, StringComparison.InvariantCultureIgnoreCase);
                var frameCounterStrategy = isMultiGateway ? this.frameCounterUpdateStrategyFactory.GetMultiGatewayStrategy() : this.frameCounterUpdateStrategyFactory.GetSingleGatewayStrategy();

                var payloadFcnt          = loraPayload.GetFcnt();
                var requiresConfirmation = loraPayload.IsConfirmed();

                using (new LoRaDeviceFrameCounterSession(loRaDevice, frameCounterStrategy))
                {
                    // 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
                    var isFrameCounterFromNewlyStartedDevice = false;
                    if (payloadFcnt <= 1)
                    {
                        if (loRaDevice.IsABP)
                        {
                            if (loRaDevice.IsABPRelaxedFrameCounter && loRaDevice.FCntUp >= 0 && payloadFcnt <= 1)
                            {
                                // known problem when device restarts, starts fcnt from zero
                                _ = frameCounterStrategy.ResetAsync(loRaDevice);
                                isFrameCounterFromNewlyStartedDevice = true;
                            }
                        }
                        else if (loRaDevice.FCntUp == payloadFcnt && payloadFcnt == 0)
                        {
                            // Some devices start with frame count 0
                            isFrameCounterFromNewlyStartedDevice = true;
                        }
                    }

                    // 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)
                    var isConfirmedResubmit = false;
                    if (!isFrameCounterFromNewlyStartedDevice && payloadFcnt <= loRaDevice.FCntUp)
                    {
                        // if it is confirmed most probably we did not ack in time before or device lost the ack packet so we should continue but not send the msg to iothub
                        if (requiresConfirmation && payloadFcnt == loRaDevice.FCntUp)
                        {
                            if (!loRaDevice.ValidateConfirmResubmit(payloadFcnt))
                            {
                                Logger.Log(loRaDevice.DevEUI, $"resubmit from confirmed message exceeds threshold of {LoRaDevice.MaxConfirmationResubmitCount}, message ignored, msg: {payloadFcnt} server: {loRaDevice.FCntUp}", LogLevel.Debug);
                                processLogger.LogLevel = LogLevel.Debug;
                                return(null);
                            }

                            isConfirmedResubmit = true;
                            Logger.Log(loRaDevice.DevEUI, $"resubmit from confirmed message detected, msg: {payloadFcnt} server: {loRaDevice.FCntUp}", LogLevel.Information);
                        }
                        else
                        {
                            Logger.Log(loRaDevice.DevEUI, $"invalid frame counter, message ignored, msg: {payloadFcnt} server: {loRaDevice.FCntUp}", LogLevel.Information);
                            return(null);
                        }
                    }

                    var fcntDown = 0;
                    // 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 frameCounterStrategy.NextFcntDown(loRaDevice, payloadFcnt);

                        // 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)
                        {
                            // update our fcntup anyway?
                            // loRaDevice.SetFcntUp(payloadFcnt);
                            Logger.Log(loRaDevice.DevEUI, "another gateway has already sent ack or downlink msg", LogLevel.Information);

                            return(null);
                        }

                        Logger.Log(loRaDevice.DevEUI, $"down frame counter: {loRaDevice.FCntDown}", LogLevel.Information);
                    }

                    if (!isConfirmedResubmit)
                    {
                        var validFcntUp = isFrameCounterFromNewlyStartedDevice || (payloadFcnt > loRaDevice.FCntUp);
                        if (validFcntUp)
                        {
                            Logger.Log(loRaDevice.DevEUI, $"valid frame counter, msg: {payloadFcnt} server: {loRaDevice.FCntUp}", LogLevel.Information);

                            object payloadData = null;

                            // if it is an upward acknowledgement from the device it does not have a payload
                            // This is confirmation from leaf device that he received a C2D confirmed
                            // if a message payload is null we don't try to decrypt it.
                            if (loraPayload.Frmpayload.Length != 0)
                            {
                                byte[] decryptedPayloadData = null;
                                try
                                {
                                    decryptedPayloadData = loraPayload.GetDecryptedPayload(loRaDevice.AppSKey);
                                }
                                catch (Exception ex)
                                {
                                    Logger.Log(loRaDevice.DevEUI, $"failed to decrypt message: {ex.Message}", LogLevel.Error);
                                }

                                var fportUp = loraPayload.GetFPort();

                                if (string.IsNullOrEmpty(loRaDevice.SensorDecoder))
                                {
                                    Logger.Log(loRaDevice.DevEUI, $"no decoder set in device twin. port: {fportUp}", LogLevel.Debug);
                                    payloadData = Convert.ToBase64String(decryptedPayloadData);
                                }
                                else
                                {
                                    Logger.Log(loRaDevice.DevEUI, $"decoding with: {loRaDevice.SensorDecoder} port: {fportUp}", LogLevel.Debug);
                                    payloadData = await this.payloadDecoder.DecodeMessageAsync(decryptedPayloadData, fportUp, loRaDevice.SensorDecoder);
                                }
                            }

                            if (!await this.SendDeviceEventAsync(loRaDevice, rxpk, payloadData, loraPayload, timeWatcher))
                            {
                                // failed to send event to IoT Hub, stop now
                                return(null);
                            }

                            loRaDevice.SetFcntUp(payloadFcnt);
                        }
                        else
                        {
                            Logger.Log(loRaDevice.DevEUI, $"invalid frame counter, msg: {payloadFcnt} server: {loRaDevice.FCntUp}", LogLevel.Information);
                        }
                    }

                    // 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()}), sending only ACK to gateway", LogLevel.Information);
                        }

                        return(null);
                    }

                    // 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))
                    {
                        return(this.CreateDownlinkMessage(
                                   null,
                                   loRaDevice,
                                   rxpk,
                                   loraPayload,
                                   timeWatcher,
                                   devAddr,
                                   false, // fpending
                                   (ushort)fcntDown));
                    }

                    // Flag indicating if there is another C2D message waiting
                    var fpending = false;

                    // Contains the Cloud to message we need to send
                    Message cloudToDeviceMessage = null;

                    if (loRaDevice.DownlinkEnabled)
                    {
                        // 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 loRaDevice.ReceiveCloudToDeviceAsync(timeAvailableToCheckCloudToDeviceMessages);

                            if (cloudToDeviceMessage != null && !this.ValidateCloudToDeviceMessage(loRaDevice, cloudToDeviceMessage))
                            {
                                _ = loRaDevice.CompleteCloudToDeviceMessageAsync(cloudToDeviceMessage);
                                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 frameCounterStrategy.NextFcntDown(loRaDevice, payloadFcnt);

                                    if (fcntDown == 0)
                                    {
                                        // We did not get a valid frame count down, therefore we should not process the message
                                        _ = loRaDevice.AbandonCloudToDeviceMessageAsync(cloudToDeviceMessage);

                                        cloudToDeviceMessage = null;
                                    }
                                    else
                                    {
                                        requiresConfirmation = true;
                                    }

                                    Logger.Log(loRaDevice.DevEUI, $"down frame counter: {loRaDevice.FCntDown}", LogLevel.Information);
                                }

                                // 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 loRaDevice.ReceiveCloudToDeviceAsync(LoRaOperationTimeWatcher.MinimumAvailableTimeToCheckForCloudMessage);

                                        if (additionalMsg != null)
                                        {
                                            fpending = true;
                                            _        = loRaDevice.AbandonCloudToDeviceMessageAsync(additionalMsg);
                                            Logger.Log(loRaDevice.DevEUI, $"found fpending c2d message id: {additionalMsg.MessageId ?? "undefined"}", LogLevel.Information);
                                        }
                                    }
                                }
                            }
                        }
                    }

                    // No C2D message and request was not confirmed, return nothing
                    if (!requiresConfirmation)
                    {
                        return(null);
                    }

                    var confirmDownstream = this.CreateDownlinkMessage(
                        cloudToDeviceMessage,
                        loRaDevice,
                        rxpk,
                        loraPayload,
                        timeWatcher,
                        devAddr,
                        fpending,
                        (ushort)fcntDown);

                    if (cloudToDeviceMessage != null)
                    {
                        if (confirmDownstream == null)
                        {
                            Logger.Log(loRaDevice.DevEUI, $"out of time for downstream message, will abandon c2d message id: {cloudToDeviceMessage.MessageId ?? "undefined"}", LogLevel.Information);
                            _ = loRaDevice.AbandonCloudToDeviceMessageAsync(cloudToDeviceMessage);
                        }
                        else
                        {
                            _ = loRaDevice.CompleteCloudToDeviceMessageAsync(cloudToDeviceMessage);
                        }
                    }

                    return(confirmDownstream);
                }
            }
        }