/// <summary>
/// Process OTAA join request
/// </summary>
async Task ProcessJoinRequestAsync(LoRaRequest request)
{
LoRaDevice loRaDevice = null;
string devEUI = null;
var loraRegion = request.Region;
try
{
var timeWatcher = new LoRaOperationTimeWatcher(loraRegion, request.StartTime);
var joinReq = (LoRaPayloadJoinRequest)request.Payload;
byte[] udpMsgForPktForwarder = new byte[0];
devEUI = joinReq.GetDevEUIAsString();
var appEUI = joinReq.GetAppEUIAsString();
var devNonce = joinReq.GetDevNonceAsString();
Logger.Log(devEUI, $"join request received", LogLevel.Information);
loRaDevice = await this.deviceRegistry.GetDeviceForJoinRequestAsync(devEUI, appEUI, devNonce);
if (loRaDevice == null)
{
request.NotifyFailed(devEUI, LoRaDeviceRequestFailedReason.UnknownDevice);
// we do not log here as we assume that the deviceRegistry does a more informed logging if returning null
return;
}
if (string.IsNullOrEmpty(loRaDevice.AppKey))
{
Logger.Log(loRaDevice.DevEUI, "join refused: missing AppKey for OTAA device", LogLevel.Error);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.InvalidJoinRequest);
return;
}
if (loRaDevice.AppEUI != appEUI)
{
Logger.Log(devEUI, "join refused: AppEUI for OTAA does not match device", LogLevel.Error);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.InvalidJoinRequest);
return;
}
if (!joinReq.CheckMic(loRaDevice.AppKey))
{
Logger.Log(devEUI, "join refused: invalid MIC", LogLevel.Error);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.JoinMicCheckFailed);
return;
}
// Make sure that is a new request and not a replay
if (!string.IsNullOrEmpty(loRaDevice.DevNonce) && loRaDevice.DevNonce == devNonce)
{
if (string.IsNullOrEmpty(loRaDevice.GatewayID))
{
Logger.Log(devEUI, "join refused: join already processed by another gateway", LogLevel.Information);
}
else
{
Logger.Log(devEUI, "join refused: DevNonce already used by this device", LogLevel.Error);
}
loRaDevice.IsOurDevice = false;
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.JoinDevNonceAlreadyUsed);
return;
}
// Check that the device is joining through the linked gateway and not another
if (!string.IsNullOrEmpty(loRaDevice.GatewayID) && !string.Equals(loRaDevice.GatewayID, this.configuration.GatewayID, StringComparison.InvariantCultureIgnoreCase))
{
Logger.Log(devEUI, $"join refused: trying to join not through its linked gateway, ignoring join request", LogLevel.Information);
loRaDevice.IsOurDevice = false;
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.HandledByAnotherGateway);
return;
}
var netIdBytes = BitConverter.GetBytes(this.configuration.NetId);
var netId = new byte[3]
{
netIdBytes[0],
netIdBytes[1],
netIdBytes[2]
};
var appNonce = OTAAKeysGenerator.GetAppNonce();
var appNonceBytes = LoRaTools.Utils.ConversionHelper.StringToByteArray(appNonce);
var appKeyBytes = LoRaTools.Utils.ConversionHelper.StringToByteArray(loRaDevice.AppKey);
var appSKey = OTAAKeysGenerator.CalculateKey(new byte[1] {
0x02
}, appNonceBytes, netId, joinReq.DevNonce, appKeyBytes);
var nwkSKey = OTAAKeysGenerator.CalculateKey(new byte[1] {
0x01
}, appNonceBytes, netId, joinReq.DevNonce, appKeyBytes);
var devAddr = OTAAKeysGenerator.GetNwkId(netId);
var oldDevAddr = loRaDevice.DevAddr;
if (!timeWatcher.InTimeForJoinAccept())
{
// in this case it's too late, we need to break and avoid saving twins
Logger.Log(devEUI, $"join refused: processing of the join request took too long, sending no message", LogLevel.Information);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.ReceiveWindowMissed);
return;
}
var updatedProperties = new LoRaDeviceJoinUpdateProperties
{
DevAddr = devAddr,
NwkSKey = nwkSKey,
AppSKey = appSKey,
AppNonce = appNonce,
DevNonce = devNonce,
NetID = ConversionHelper.ByteArrayToString(netId),
Region = request.Region.LoRaRegion,
PreferredGatewayID = this.configuration.GatewayID,
};
if (loRaDevice.ClassType == LoRaDeviceClassType.C)
{
updatedProperties.SavePreferredGateway = true;
updatedProperties.SaveRegion = true;
}
var deviceUpdateSucceeded = await loRaDevice.UpdateAfterJoinAsync(updatedProperties);
if (!deviceUpdateSucceeded)
{
Logger.Log(devEUI, $"join refused: join request could not save twin", LogLevel.Error);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.ApplicationError);
return;
}
var windowToUse = timeWatcher.ResolveJoinAcceptWindowToUse(loRaDevice);
if (windowToUse == Constants.INVALID_RECEIVE_WINDOW)
{
Logger.Log(devEUI, $"join refused: processing of the join request took too long, sending no message", LogLevel.Information);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.ReceiveWindowMissed);
return;
}
double freq = 0;
string datr = null;
uint tmst = 0;
if (windowToUse == Constants.RECEIVE_WINDOW_1)
{
datr = loraRegion.GetDownstreamDR(request.Rxpk);
if (!loraRegion.TryGetUpstreamChannelFrequency(request.Rxpk, out freq) || datr == null)
{
Logger.Log(loRaDevice.DevEUI, "could not resolve DR and/or frequency for downstream", LogLevel.Error);
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.InvalidRxpk);
return;
}
// set tmst for the normal case
tmst = request.Rxpk.Tmst + loraRegion.Join_accept_delay1 * 1000000;
}
else
{
Logger.Log(devEUI, $"processing of the join request took too long, using second join accept receive window", LogLevel.Debug);
tmst = request.Rxpk.Tmst + loraRegion.Join_accept_delay2 * 1000000;
(freq, datr) = loraRegion.GetDownstreamRX2DRAndFreq(devEUI, this.configuration.Rx2DataRate, this.configuration.Rx2DataFrequency, null);
}
loRaDevice.IsOurDevice = true;
this.deviceRegistry.UpdateDeviceAfterJoin(loRaDevice, oldDevAddr);
// Build join accept downlink message
Array.Reverse(netId);
Array.Reverse(appNonceBytes);
// Build the DlSettings fields that is a superposition of RX2DR and RX1DROffset field
byte[] dlSettings = new byte[1];
if (request.Region.DRtoConfiguration.ContainsKey(loRaDevice.DesiredRX2DataRate))
{
dlSettings[0] =
(byte)(loRaDevice.DesiredRX2DataRate & 0b00001111);
}
else
{
Logger.Log(devEUI, $"twin RX2 DR value is not within acceptable values", LogLevel.Error);
}
if (request.Region.IsValidRX1DROffset(loRaDevice.DesiredRX1DROffset))
{
var rx1droffset = (byte)(loRaDevice.DesiredRX1DROffset << 4);
dlSettings[0] = (byte)(dlSettings[0] + rx1droffset);
}
else
{
Logger.Log(devEUI, $"twin RX1 offset DR value is not within acceptable values", LogLevel.Error);
}
ushort rxDelay = 0;
if (request.Region.IsValidRXDelay(loRaDevice.DesiredRXDelay))
{
rxDelay = loRaDevice.DesiredRXDelay;
}
else
{
Logger.Log(devEUI, $"twin RX delay value is not within acceptable values", LogLevel.Error);
}
var loRaPayloadJoinAccept = new LoRaPayloadJoinAccept(
LoRaTools.Utils.ConversionHelper.ByteArrayToString(netId), // NETID 0 / 1 is default test
ConversionHelper.StringToByteArray(devAddr), // todo add device address management
appNonceBytes,
dlSettings,
rxDelay,
null);
var joinAccept = loRaPayloadJoinAccept.Serialize(loRaDevice.AppKey, datr, freq, tmst, devEUI);
if (joinAccept != null)
{
_ = request.PacketForwarder.SendDownstreamAsync(joinAccept);
request.NotifySucceeded(loRaDevice, joinAccept);
if (Logger.LoggerLevel <= LogLevel.Debug)
{
var jsonMsg = JsonConvert.SerializeObject(joinAccept);
Logger.Log(devEUI, $"{LoRaMessageType.JoinAccept.ToString()} {jsonMsg}", LogLevel.Debug);
}
else if (Logger.LoggerLevel == LogLevel.Information)
{
Logger.Log(devEUI, "join accepted", LogLevel.Information);
}
}
}
catch (Exception ex)
{
var deviceId = devEUI ?? ConversionHelper.ByteArrayToString(request.Payload.DevAddr);
Logger.Log(deviceId, $"failed to handle join request. {ex.Message}", LogLevel.Error);
request.NotifyFailed(loRaDevice, ex);
}
}
/// <summary>
/// Creates downlink message with ack for confirmation or cloud to device message.
/// </summary>
internal static DownlinkMessageBuilderResponse CreateDownlinkMessage(
NetworkServerConfiguration configuration,
LoRaDevice loRaDevice,
LoRaRequest request,
LoRaOperationTimeWatcher timeWatcher,
IReceivedLoRaCloudToDeviceMessage cloudToDeviceMessage,
bool fpending,
uint fcntDown,
LoRaADRResult loRaADRResult,
ILogger logger)
{
var fcntDownToSend = ValidateAndConvert16bitFCnt(fcntDown);
var upstreamPayload = (LoRaPayloadData)request.Payload;
var radioMetadata = request.RadioMetadata;
var loRaRegion = request.Region;
var isMessageTooLong = false;
// default fport
var fctrl = FrameControlFlags.None;
if (upstreamPayload.MessageType == MacMessageType.ConfirmedDataUp)
{
// Confirm receiving message to device
fctrl = FrameControlFlags.Ack;
}
// Calculate receive window
var receiveWindow = timeWatcher.ResolveReceiveWindowToUse(loRaDevice);
if (receiveWindow is null)
{
// No valid receive window. Abandon the message
isMessageTooLong = true;
return(new DownlinkMessageBuilderResponse(null, isMessageTooLong, receiveWindow));
}
var rndToken = new byte[2];
RndKeysGenerator.GetBytes(rndToken);
DataRateIndex datr;
Hertz freq;
var deviceJoinInfo = request.Region.LoRaRegion == LoRaRegionType.CN470RP2
? new DeviceJoinInfo(loRaDevice.ReportedCN470JoinChannel, loRaDevice.DesiredCN470JoinChannel)
: null;
if (loRaRegion is DwellTimeLimitedRegion someRegion)
{
someRegion.UseDwellTimeSetting(loRaDevice.ReportedDwellTimeSetting);
}
if (receiveWindow is ReceiveWindow2)
{
freq = loRaRegion.GetDownstreamRX2Freq(configuration.Rx2Frequency, deviceJoinInfo, logger);
datr = loRaRegion.GetDownstreamRX2DataRate(configuration.Rx2DataRate, loRaDevice.ReportedRX2DataRate, deviceJoinInfo, logger);
}
else
{
datr = loRaRegion.GetDownstreamDataRate(radioMetadata.DataRate, loRaDevice.ReportedRX1DROffset);
// The logic for passing CN470 join channel will change as part of #561
if (!loRaRegion.TryGetDownstreamChannelFrequency(radioMetadata.Frequency, upstreamDataRate: radioMetadata.DataRate, deviceJoinInfo: deviceJoinInfo, downstreamFrequency: out freq))
{
logger.LogError("there was a problem in setting the frequency in the downstream message settings");
return(new DownlinkMessageBuilderResponse(null, false, receiveWindow));
}
}
var rx2 = new ReceiveWindow(loRaRegion.GetDownstreamRX2DataRate(configuration.Rx2DataRate, loRaDevice.ReportedRX2DataRate, deviceJoinInfo, logger),
loRaRegion.GetDownstreamRX2Freq(configuration.Rx2Frequency, deviceJoinInfo, logger));
// get max. payload size based on data rate from LoRaRegion
var maxPayloadSize = loRaRegion.GetMaxPayloadSize(datr);
// Deduct 8 bytes from max payload size.
maxPayloadSize -= Constants.LoraProtocolOverheadSize;
var availablePayloadSize = maxPayloadSize;
var macCommands = new List <MacCommand>();
FramePort?fport = null;
var requiresDeviceAcknowlegement = false;
var macCommandType = Cid.Zero;
byte[] frmPayload = null;
if (cloudToDeviceMessage != null)
{
// Get C2D Mac coomands
var macCommandsC2d = PrepareMacCommandAnswer(null, cloudToDeviceMessage.MacCommands, request, null, logger);
// Calculate total C2D payload size
var totalC2dSize = cloudToDeviceMessage.GetPayload()?.Length ?? 0;
totalC2dSize += macCommandsC2d?.Sum(x => x.Length) ?? 0;
// Total C2D payload will fit
if (availablePayloadSize >= totalC2dSize)
{
// Add frmPayload
frmPayload = cloudToDeviceMessage.GetPayload();
// Add C2D Mac commands
if (macCommandsC2d?.Count > 0)
{
foreach (var macCommand in macCommandsC2d)
{
macCommands.Add(macCommand);
}
}
// Deduct frmPayload size from available payload size, continue processing and log
availablePayloadSize -= (uint)totalC2dSize;
if (cloudToDeviceMessage.Confirmed)
{
requiresDeviceAcknowlegement = true;
loRaDevice.LastConfirmedC2DMessageID = cloudToDeviceMessage.MessageId ?? Constants.C2D_MSG_ID_PLACEHOLDER;
}
if (cloudToDeviceMessage.Fport.IsAppSpecific() || cloudToDeviceMessage.Fport.IsReserved())
{
fport = cloudToDeviceMessage.Fport;
}
logger.LogInformation($"cloud to device message: {((frmPayload?.Length ?? 0) == 0 ? "empty" : frmPayload.ToHex())}, id: {cloudToDeviceMessage.MessageId ?? "undefined"}, fport: {(byte)(fport ?? FramePort.MacCommand)}, confirmed: {requiresDeviceAcknowlegement}, cidType: {macCommandType}, macCommand: {macCommands.Count > 0}");
}
else
{
// Flag message to be abandoned and log`
logger.LogDebug($"cloud to device message: empty, id: {cloudToDeviceMessage.MessageId ?? "undefined"}, fport: 0, confirmed: {requiresDeviceAcknowlegement} too long for current receive window. Abandoning.");
isMessageTooLong = true;
}
}
// Get request Mac commands
var macCommandsRequest = PrepareMacCommandAnswer(upstreamPayload.MacCommands, null, request, loRaADRResult, logger);
// Calculate request Mac commands size
var macCommandsRequestSize = macCommandsRequest?.Sum(x => x.Length) ?? 0;
// Try adding request Mac commands
if (availablePayloadSize >= macCommandsRequestSize)
{
if (macCommandsRequest?.Count > 0)
{
foreach (var macCommand in macCommandsRequest)
{
macCommands.Add(macCommand);
}
}
}
if (fpending || isMessageTooLong)
{
fctrl |= FrameControlFlags.DownlinkFramePending;
}
if (upstreamPayload.IsDataRateNetworkControlled)
{
fctrl |= FrameControlFlags.Adr;
}
var msgType = requiresDeviceAcknowlegement ? MacMessageType.ConfirmedDataDown : MacMessageType.UnconfirmedDataDown;
var ackLoRaMessage = new LoRaPayloadData(
msgType,
upstreamPayload.DevAddr,
fctrl,
fcntDownToSend,
macCommands,
fport,
frmPayload,
1,
loRaDevice.Supports32BitFCnt ? fcntDown : null);
// following calculation is making sure that ReportedRXDelay is chosen if not default,
// todo: check the device twin preference if using confirmed or unconfirmed down
var downlinkMessage = BuildDownstreamMessage(loRaDevice,
request.StationEui,
logger,
radioMetadata.UpInfo.Xtime,
receiveWindow is ReceiveWindow2 ? null : new ReceiveWindow(datr, freq),
rx2,
loRaDevice.ReportedRXDelay,
ackLoRaMessage,
loRaDevice.ClassType,
radioMetadata.UpInfo.AntennaPreference);
if (logger.IsEnabled(LogLevel.Debug))
{
logger.LogDebug($"{ackLoRaMessage.MessageType} {JsonConvert.SerializeObject(downlinkMessage)}");
}
return(new DownlinkMessageBuilderResponse(downlinkMessage, isMessageTooLong, receiveWindow));
}
/// <summary>
/// Creates downlink message with ack for confirmation or cloud to device message
/// </summary>
internal static DownlinkMessageBuilderResponse CreateDownlinkMessage(
NetworkServerConfiguration configuration,
LoRaDevice loRaDevice,
LoRaRequest request,
LoRaOperationTimeWatcher timeWatcher,
IReceivedLoRaCloudToDeviceMessage cloudToDeviceMessage,
bool fpending,
uint fcntDown,
LoRaADRResult loRaADRResult)
{
var fcntDownToSend = ValidateAndConvert16bitFCnt(fcntDown);
var upstreamPayload = (LoRaPayloadData)request.Payload;
var rxpk = request.Rxpk;
var loRaRegion = request.Region;
bool isMessageTooLong = false;
// default fport
byte fctrl = 0;
if (upstreamPayload.LoRaMessageType == LoRaMessageType.ConfirmedDataUp)
{
// Confirm receiving message to device
fctrl = (byte)FctrlEnum.Ack;
}
// Calculate receive window
var receiveWindow = timeWatcher.ResolveReceiveWindowToUse(loRaDevice);
if (receiveWindow == Constants.INVALID_RECEIVE_WINDOW)
{
// No valid receive window. Abandon the message
isMessageTooLong = true;
return(new DownlinkMessageBuilderResponse(null, isMessageTooLong));
}
byte[] rndToken = new byte[2];
lock (RndLock)
{
RndDownlinkMessageBuilder.NextBytes(rndToken);
}
string datr;
double freq;
long tmst;
if (receiveWindow == Constants.RECEIVE_WINDOW_2)
{
tmst = rxpk.Tmst + CalculateTime(timeWatcher.GetReceiveWindow2Delay(loRaDevice), loRaDevice.ReportedRXDelay);
(freq, datr) = loRaRegion.GetDownstreamRX2DRAndFreq(loRaDevice.DevEUI, configuration.Rx2DataRate, configuration.Rx2DataFrequency, loRaDevice.ReportedRX2DataRate);
}
else
{
datr = loRaRegion.GetDownstreamDR(rxpk, (uint)loRaDevice.ReportedRX1DROffset);
if (datr == null)
{
Logger.Log(loRaDevice.DevEUI, "there was a problem in setting the data rate in the downstream message packet forwarder settings", LogLevel.Error);
return(new DownlinkMessageBuilderResponse(null, false));
}
if (!loRaRegion.TryGetUpstreamChannelFrequency(rxpk, out freq))
{
Logger.Log(loRaDevice.DevEUI, "there was a problem in setting the frequency in the downstream message packet forwarder settings", LogLevel.Error);
return(new DownlinkMessageBuilderResponse(null, false));
}
tmst = rxpk.Tmst + CalculateTime(timeWatcher.GetReceiveWindow1Delay(loRaDevice), loRaDevice.ReportedRXDelay);
}
// get max. payload size based on data rate from LoRaRegion
var maxPayloadSize = loRaRegion.GetMaxPayloadSize(datr);
// Deduct 8 bytes from max payload size.
maxPayloadSize -= Constants.LORA_PROTOCOL_OVERHEAD_SIZE;
var availablePayloadSize = maxPayloadSize;
var macCommands = new List <MacCommand>();
byte?fport = null;
var requiresDeviceAcknowlegement = false;
var macCommandType = CidEnum.Zero;
byte[] frmPayload = null;
if (cloudToDeviceMessage != null)
{
// Get C2D Mac coomands
var macCommandsC2d = PrepareMacCommandAnswer(loRaDevice.DevEUI, null, cloudToDeviceMessage?.MacCommands, rxpk, null);
// Calculate total C2D payload size
var totalC2dSize = cloudToDeviceMessage.GetPayload()?.Length ?? 0;
totalC2dSize += macCommandsC2d?.Sum(x => x.Length) ?? 0;
// Total C2D payload will fit
if (availablePayloadSize >= totalC2dSize)
{
// Add frmPayload
frmPayload = cloudToDeviceMessage.GetPayload();
// Add C2D Mac commands
if (macCommandsC2d?.Count > 0)
{
foreach (MacCommand macCommand in macCommandsC2d)
{
macCommands.Add(macCommand);
}
}
// Deduct frmPayload size from available payload size, continue processing and log
availablePayloadSize -= (uint)totalC2dSize;
if (cloudToDeviceMessage.Confirmed)
{
requiresDeviceAcknowlegement = true;
loRaDevice.LastConfirmedC2DMessageID = cloudToDeviceMessage.MessageId ?? Constants.C2D_MSG_ID_PLACEHOLDER;
}
if (cloudToDeviceMessage.Fport > 0)
{
fport = cloudToDeviceMessage.Fport;
}
Logger.Log(loRaDevice.DevEUI, $"cloud to device message: {((frmPayload?.Length ?? 0) == 0 ? "empty" : ConversionHelper.ByteArrayToString(frmPayload))}, id: {cloudToDeviceMessage.MessageId ?? "undefined"}, fport: {fport ?? 0}, confirmed: {requiresDeviceAcknowlegement}, cidType: {macCommandType}, macCommand: {macCommands.Count > 0}", LogLevel.Information);
Array.Reverse(frmPayload);
}
else
{
// Flag message to be abandoned and log
Logger.Log(loRaDevice.DevEUI, $"cloud to device message: {((frmPayload?.Length ?? 0) == 0 ? "empty" : Encoding.UTF8.GetString(frmPayload))}, id: {cloudToDeviceMessage.MessageId ?? "undefined"}, fport: {fport ?? 0}, confirmed: {requiresDeviceAcknowlegement} too long for current receive window. Abandoning.", LogLevel.Debug);
isMessageTooLong = true;
}
}
// Get request Mac commands
var macCommandsRequest = PrepareMacCommandAnswer(loRaDevice.DevEUI, upstreamPayload.MacCommands, null, rxpk, loRaADRResult);
// Calculate request Mac commands size
var macCommandsRequestSize = macCommandsRequest?.Sum(x => x.Length) ?? 0;
// Try adding request Mac commands
if (availablePayloadSize >= macCommandsRequestSize)
{
if (macCommandsRequest?.Count > 0)
{
foreach (MacCommand macCommand in macCommandsRequest)
{
macCommands.Add(macCommand);
}
}
}
if (fpending || isMessageTooLong)
{
fctrl |= (int)FctrlEnum.FpendingOrClassB;
}
if (upstreamPayload.IsAdrEnabled)
{
fctrl |= (byte)FctrlEnum.ADR;
}
var srcDevAddr = upstreamPayload.DevAddr.Span;
var reversedDevAddr = new byte[srcDevAddr.Length];
for (int i = reversedDevAddr.Length - 1; i >= 0; --i)
{
reversedDevAddr[i] = srcDevAddr[srcDevAddr.Length - (1 + i)];
}
var msgType = requiresDeviceAcknowlegement ? LoRaMessageType.ConfirmedDataDown : LoRaMessageType.UnconfirmedDataDown;
var ackLoRaMessage = new LoRaPayloadData(
msgType,
reversedDevAddr,
new byte[] { fctrl },
BitConverter.GetBytes(fcntDownToSend),
macCommands,
fport.HasValue ? new byte[] { fport.Value } : null,
frmPayload,
1,
loRaDevice.Supports32BitFCnt ? fcntDown : (uint?)null);
// todo: check the device twin preference if using confirmed or unconfirmed down
Logger.Log(loRaDevice.DevEUI, $"sending a downstream message with ID {ConversionHelper.ByteArrayToString(rndToken)}", LogLevel.Information);
return(new DownlinkMessageBuilderResponse(
ackLoRaMessage.Serialize(loRaDevice.AppSKey, loRaDevice.NwkSKey, datr, freq, tmst, loRaDevice.DevEUI),
isMessageTooLong));
}
internal ProcessLogger(LoRaOperationTimeWatcher timeWatcher, ReadOnlyMemory <byte> devAddr)
{
this.timeWatcher = timeWatcher;
this.devAddr = devAddr;
this.LogLevel = LogLevel.Information;
}
private async Task <bool> SendDeviceEventAsync(LoRaRequest request, LoRaDevice loRaDevice, LoRaOperationTimeWatcher timeWatcher, object decodedValue, DeduplicationResult deduplicationResult, byte[] decryptedPayloadData)
{
var loRaPayloadData = (LoRaPayloadData)request.Payload;
var deviceTelemetry = new LoRaDeviceTelemetry(request.Rxpk, loRaPayloadData, decodedValue, decryptedPayloadData)
{
DeviceEUI = loRaDevice.DevEUI,
GatewayID = this.configuration.GatewayID,
Edgets = (long)(timeWatcher.Start - DateTime.UnixEpoch).TotalMilliseconds
};
if (deduplicationResult != null && deduplicationResult.IsDuplicate)
{
deviceTelemetry.DupMsg = true;
}
Dictionary <string, string> eventProperties = null;
if (loRaPayloadData.IsUpwardAck())
{
eventProperties = new Dictionary <string, string>();
Logger.Log(loRaDevice.DevEUI, $"message ack received for cloud to device message id {loRaDevice.LastConfirmedC2DMessageID}", LogLevel.Information);
eventProperties.Add(Constants.C2D_MSG_PROPERTY_VALUE_NAME, loRaDevice.LastConfirmedC2DMessageID ?? Constants.C2D_MSG_ID_PLACEHOLDER);
loRaDevice.LastConfirmedC2DMessageID = null;
}
this.ProcessAndSendMacCommands(loRaPayloadData, ref eventProperties);
if (await loRaDevice.SendEventAsync(deviceTelemetry, eventProperties))
{
string payloadAsRaw = null;
if (deviceTelemetry.Data != null)
{
payloadAsRaw = JsonConvert.SerializeObject(deviceTelemetry.Data, Formatting.None);
}
Logger.Log(loRaDevice.DevEUI, $"message '{payloadAsRaw}' sent to hub", LogLevel.Information);
return(true);
}
return(false);
}
internal ProcessLogger(LoRaOperationTimeWatcher timeWatcher)
{
this.timeWatcher = timeWatcher;
this.LogLevel = LogLevel.Information;
}
/// <summary>
/// Process OTAA join request
/// </summary>
async Task <DownlinkPktFwdMessage> ProcessJoinRequestAsync(Rxpk rxpk, LoRaPayloadJoinRequest joinReq, DateTime startTimeProcessing)
{
var timeWatcher = new LoRaOperationTimeWatcher(this.loraRegion, startTimeProcessing);
using (var processLogger = new ProcessLogger(timeWatcher))
{
byte[] udpMsgForPktForwarder = new byte[0];
var devEUI = joinReq.GetDevEUIAsString();
var appEUI = joinReq.GetAppEUIAsString();
// set context to logger
processLogger.SetDevEUI(devEUI);
var devNonce = joinReq.GetDevNonceAsString();
Logger.Log(devEUI, $"join request received", LogLevel.Information);
var loRaDevice = await this.deviceRegistry.GetDeviceForJoinRequestAsync(devEUI, appEUI, devNonce);
if (loRaDevice == null)
{
return(null);
}
if (string.IsNullOrEmpty(loRaDevice.AppKey))
{
Logger.Log(loRaDevice.DevEUI, "join refused: missing AppKey for OTAA device", LogLevel.Error);
return(null);
}
if (loRaDevice.AppEUI != appEUI)
{
Logger.Log(devEUI, "join refused: AppEUI for OTAA does not match device", LogLevel.Error);
return(null);
}
if (!joinReq.CheckMic(loRaDevice.AppKey))
{
Logger.Log(devEUI, "join refused: invalid MIC", LogLevel.Error);
return(null);
}
// Make sure that is a new request and not a replay
if (!string.IsNullOrEmpty(loRaDevice.DevNonce) && loRaDevice.DevNonce == devNonce)
{
Logger.Log(devEUI, "join refused: DevNonce already used by this device", LogLevel.Information);
loRaDevice.IsOurDevice = false;
return(null);
}
// Check that the device is joining through the linked gateway and not another
if (!string.IsNullOrEmpty(loRaDevice.GatewayID) && !string.Equals(loRaDevice.GatewayID, this.configuration.GatewayID, StringComparison.InvariantCultureIgnoreCase))
{
Logger.Log(devEUI, $"join refused: trying to join not through its linked gateway, ignoring join request", LogLevel.Information);
loRaDevice.IsOurDevice = false;
return(null);
}
var netIdBytes = BitConverter.GetBytes(this.configuration.NetId);
var netId = new byte[3]
{
netIdBytes[0],
netIdBytes[1],
netIdBytes[2]
};
var appNonce = OTAAKeysGenerator.GetAppNonce();
var appNonceBytes = LoRaTools.Utils.ConversionHelper.StringToByteArray(appNonce);
var appKeyBytes = LoRaTools.Utils.ConversionHelper.StringToByteArray(loRaDevice.AppKey);
var appSKey = OTAAKeysGenerator.CalculateKey(new byte[1] {
0x02
}, appNonceBytes, netId, joinReq.DevNonce, appKeyBytes);
var nwkSKey = OTAAKeysGenerator.CalculateKey(new byte[1] {
0x01
}, appNonceBytes, netId, joinReq.DevNonce, appKeyBytes);
var devAddr = OTAAKeysGenerator.GetNwkId(netId);
if (!timeWatcher.InTimeForJoinAccept())
{
// in this case it's too late, we need to break and avoid saving twins
Logger.Log(devEUI, $"join refused: processing of the join request took too long, sending no message", LogLevel.Information);
return(null);
}
Logger.Log(loRaDevice.DevEUI, $"saving join properties twins", LogLevel.Debug);
var deviceUpdateSucceeded = await loRaDevice.UpdateAfterJoinAsync(devAddr, nwkSKey, appSKey, appNonce, devNonce, LoRaTools.Utils.ConversionHelper.ByteArrayToString(netId));
Logger.Log(loRaDevice.DevEUI, $"done saving join properties twins", LogLevel.Debug);
if (!deviceUpdateSucceeded)
{
Logger.Log(devEUI, $"join refused: join request could not save twins", LogLevel.Error);
return(null);
}
var windowToUse = timeWatcher.ResolveJoinAcceptWindowToUse(loRaDevice);
if (windowToUse == 0)
{
Logger.Log(devEUI, $"join refused: processing of the join request took too long, sending no message", LogLevel.Information);
return(null);
}
double freq = 0;
string datr = null;
uint tmst = 0;
if (windowToUse == 1)
{
try
{
datr = this.loraRegion.GetDownstreamDR(rxpk);
freq = this.loraRegion.GetDownstreamChannelFrequency(rxpk);
}
catch (RegionLimitException ex)
{
Logger.Log(devEUI, ex.ToString(), LogLevel.Error);
}
// set tmst for the normal case
tmst = rxpk.Tmst + this.loraRegion.Join_accept_delay1 * 1000000;
}
else
{
Logger.Log(devEUI, $"processing of the join request took too long, using second join accept receive window", LogLevel.Information);
tmst = rxpk.Tmst + this.loraRegion.Join_accept_delay2 * 1000000;
if (string.IsNullOrEmpty(this.configuration.Rx2DataRate))
{
Logger.Log(devEUI, $"using standard second receive windows for join request", LogLevel.Information);
// using EU fix DR for RX2
freq = this.loraRegion.RX2DefaultReceiveWindows.frequency;
datr = this.loraRegion.DRtoConfiguration[RegionFactory.CurrentRegion.RX2DefaultReceiveWindows.dr].configuration;
}
else
{
Logger.Log(devEUI, $"using custom second receive windows for join request", LogLevel.Information);
freq = this.configuration.Rx2DataFrequency;
datr = this.configuration.Rx2DataRate;
}
}
loRaDevice.IsOurDevice = true;
this.deviceRegistry.UpdateDeviceAfterJoin(loRaDevice);
// Build join accept downlink message
Array.Reverse(netId);
Array.Reverse(appNonceBytes);
return(this.CreateJoinAcceptDownlinkMessage(
netId,
loRaDevice.AppKey,
devAddr,
appNonceBytes,
datr,
freq,
tmst,
devEUI));
}
}
// Sends device telemetry data to IoT Hub
private async Task <bool> SendDeviceEventAsync(LoRaDevice loRaDevice, Rxpk rxpk, object decodedValue, LoRaPayloadData loRaPayloadData, LoRaOperationTimeWatcher timeWatcher)
{
var deviceTelemetry = new LoRaDeviceTelemetry(rxpk, loRaPayloadData, decodedValue)
{
DeviceEUI = loRaDevice.DevEUI,
GatewayID = this.configuration.GatewayID,
Edgets = (long)(timeWatcher.Start - DateTime.UnixEpoch).TotalMilliseconds
};
Dictionary <string, string> eventProperties = null;
if (loRaPayloadData.IsUpwardAck())
{
eventProperties = new Dictionary <string, string>();
Logger.Log(loRaDevice.DevEUI, $"Message ack received for C2D message id {loRaDevice.LastConfirmedC2DMessageID}", LogLevel.Information);
eventProperties.Add(C2D_MSG_PROPERTY_VALUE_NAME, loRaDevice.LastConfirmedC2DMessageID ?? C2D_MSG_ID_PLACEHOLDER);
loRaDevice.LastConfirmedC2DMessageID = null;
}
var macCommand = loRaPayloadData.GetMacCommands();
if (macCommand.MacCommand.Count > 0)
{
eventProperties = eventProperties ?? new Dictionary <string, string>();
for (int i = 0; i < macCommand.MacCommand.Count; i++)
{
eventProperties[macCommand.MacCommand[i].Cid.ToString()] = JsonConvert.SerializeObject(macCommand.MacCommand[i], Formatting.None);
// in case it is a link check mac, we need to send it downstream.
if (macCommand.MacCommand[i].Cid == CidEnum.LinkCheckCmd)
{
// linkCheckCmdResponse = new LinkCheckCmd(rxPk.GetModulationMargin(), 1).ToBytes();
}
}
}
if (await loRaDevice.SendEventAsync(deviceTelemetry, eventProperties))
{
var payloadAsRaw = deviceTelemetry.Data as string;
if (payloadAsRaw == null && deviceTelemetry.Data != null)
{
payloadAsRaw = JsonConvert.SerializeObject(deviceTelemetry.Data, Formatting.None);
}
Logger.Log(loRaDevice.DevEUI, $"message '{payloadAsRaw}' sent to hub", LogLevel.Information);
return(true);
}
return(false);
}
/// <summary>
/// Creates downlink message with ack for confirmation or cloud to device message
/// </summary>
DownlinkPktFwdMessage CreateDownlinkMessage(
Message cloudToDeviceMessage,
LoRaDevice loRaDevice,
Rxpk rxpk,
LoRaPayloadData upstreamPayload,
LoRaOperationTimeWatcher timeWatcher,
ReadOnlyMemory <byte> payloadDevAddr,
bool fpending,
ushort fcntDown)
{
// default fport
byte fctrl = 0;
if (upstreamPayload.LoRaMessageType == LoRaMessageType.ConfirmedDataUp)
{
// Confirm receiving message to device
fctrl = (byte)FctrlEnum.Ack;
}
byte?fport = null;
var requiresDeviceAcknowlegement = false;
byte[] macbytes = null;
byte[] rndToken = new byte[2];
Random rnd = new Random();
rnd.NextBytes(rndToken);
byte[] frmPayload = null;
if (cloudToDeviceMessage != null)
{
if (cloudToDeviceMessage.Properties.TryGetValueCaseInsensitive("cidtype", out var cidTypeValue))
{
Logger.Log(loRaDevice.DevEUI, "Cloud to device MAC command received", LogLevel.Information);
MacCommandHolder macCommandHolder = new MacCommandHolder(Convert.ToByte(cidTypeValue));
macbytes = macCommandHolder.MacCommand[0].ToBytes();
}
if (cloudToDeviceMessage.Properties.TryGetValueCaseInsensitive("confirmed", out var confirmedValue) && confirmedValue.Equals("true", StringComparison.OrdinalIgnoreCase))
{
requiresDeviceAcknowlegement = true;
loRaDevice.LastConfirmedC2DMessageID = cloudToDeviceMessage.MessageId ?? C2D_MSG_ID_PLACEHOLDER;
}
if (cloudToDeviceMessage.Properties.TryGetValueCaseInsensitive("fport", out var fPortValue))
{
fport = byte.Parse(fPortValue);
}
Logger.Log(loRaDevice.DevEUI, $"Sending a downstream message with ID {ConversionHelper.ByteArrayToString(rndToken)}", LogLevel.Debug);
frmPayload = cloudToDeviceMessage?.GetBytes();
Logger.Log(loRaDevice.DevEUI, $"C2D message: {Encoding.UTF8.GetString(frmPayload)}, id: {cloudToDeviceMessage.MessageId ?? "undefined"}, fport: {fport}, confirmed: {requiresDeviceAcknowlegement}, cidType: {cidTypeValue}", LogLevel.Information);
// cut to the max payload of lora for any EU datarate
if (frmPayload.Length > 51)
{
Array.Resize(ref frmPayload, 51);
}
Array.Reverse(frmPayload);
}
if (fpending)
{
fctrl |= (int)FctrlEnum.FpendingOrClassB;
}
// if (macbytes != null && linkCheckCmdResponse != null)
// macbytes = macbytes.Concat(linkCheckCmdResponse).ToArray();
var reversedDevAddr = new byte[payloadDevAddr.Length];
var srcDevAddr = payloadDevAddr.Span;
for (int i = reversedDevAddr.Length - 1; i >= 0; --i)
{
reversedDevAddr[i] = srcDevAddr[srcDevAddr.Length - (1 + i)];
}
var msgType = requiresDeviceAcknowlegement ? LoRaMessageType.ConfirmedDataDown : LoRaMessageType.UnconfirmedDataDown;
var ackLoRaMessage = new LoRaPayloadData(
msgType,
reversedDevAddr,
new byte[] { fctrl },
BitConverter.GetBytes(fcntDown),
macbytes,
fport.HasValue ? new byte[] { fport.Value } : null,
frmPayload,
1);
// var firstWindowTime = timeWatcher.GetRemainingTimeToReceiveFirstWindow(loRaDevice);
// if (firstWindowTime > TimeSpan.Zero)
// System.Threading.Thread.Sleep(firstWindowTime);
var receiveWindow = timeWatcher.ResolveReceiveWindowToUse(loRaDevice);
if (receiveWindow == 0)
{
return(null);
}
string datr = null;
double freq = 0;
long tmst = 0;
if (receiveWindow == 2)
{
tmst = rxpk.Tmst + timeWatcher.GetReceiveWindow2Delay(loRaDevice) * 1000000;
if (string.IsNullOrEmpty(this.configuration.Rx2DataRate))
{
Logger.Log(loRaDevice.DevEUI, "using standard second receive windows", LogLevel.Information);
freq = this.loraRegion.RX2DefaultReceiveWindows.frequency;
datr = this.loraRegion.DRtoConfiguration[this.loraRegion.RX2DefaultReceiveWindows.dr].configuration;
}
// if specific twins are set, specify second channel to be as specified
else
{
freq = this.configuration.Rx2DataFrequency;
datr = this.configuration.Rx2DataRate;
Logger.Log(loRaDevice.DevEUI, $"using custom DR second receive windows freq : {freq}, datr:{datr}", LogLevel.Information);
}
}
else
{
try
{
datr = this.loraRegion.GetDownstreamDR(rxpk);
freq = this.loraRegion.GetDownstreamChannelFrequency(rxpk);
tmst = rxpk.Tmst + this.loraRegion.Receive_delay1 * 1000000;
}
catch (RegionLimitException ex)
{
Logger.Log(loRaDevice.DevEUI, ex.Message, LogLevel.Error);
return(null);
}
}
// todo: check the device twin preference if using confirmed or unconfirmed down
return(ackLoRaMessage.Serialize(loRaDevice.AppSKey, loRaDevice.NwkSKey, datr, freq, tmst, loRaDevice.DevEUI));
}
/// <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);
}
}
}