private static DownlinkMessage BuildDownstreamMessage(LoRaDevice loRaDevice,
StationEui stationEUI,
ILogger logger,
ulong xTime,
ReceiveWindow?rx1,
ReceiveWindow rx2,
RxDelay lnsRxDelay,
LoRaPayloadData loRaMessage,
LoRaDeviceClassType deviceClassType,
uint?antennaPreference = null)
{
var messageBytes = loRaMessage.Serialize(loRaDevice.AppSKey.Value, loRaDevice.NwkSKey.Value);
var downlinkMessage = new DownlinkMessage(
messageBytes,
xTime,
rx1, rx2,
loRaDevice.DevEUI,
lnsRxDelay,
deviceClassType,
stationEUI,
antennaPreference
);
if (logger.IsEnabled(LogLevel.Debug))
{
logger.LogDebug($"{loRaMessage.MessageType} {JsonConvert.SerializeObject(downlinkMessage)}");
}
return(downlinkMessage);
}
public DownlinkMessage(byte[] payload,
ulong xtime,
ReceiveWindow?rx1,
ReceiveWindow rx2,
DevEui devEui,
RxDelay lnsRxDelay,
LoRaDeviceClassType deviceClassType,
StationEui stationEui = default,
uint?antennaPreference = null)
{
if (payload is null)
{
throw new ArgumentNullException(nameof(payload));
}
Data = payload;
DevEui = devEui;
LnsRxDelay = lnsRxDelay;
DeviceClassType = deviceClassType;
AntennaPreference = antennaPreference;
Rx1 = rx1;
Rx2 = rx2;
StationEui = stationEui;
Xtime = xtime;
}
public void ProcessReceive(Context ctx)
{
if (_nextTransmitBlockNumber != 0)
{
return;
}
var signals = ReceiveWindow.OrderByDescending(s => s.SignalStrength).ToList();
ReceiveWindow.Clear();
if (signals.Count == 0)
{
if (_receiveBuffer.Count != 0)
{
var first = _receiveBuffer[0];
if (_receiveBuffer.Count == _parameters.TransmissionLengthTicks &&
_receiveBuffer.All(s => s.Transmission == first.Transmission) &&
_receiveBuffer.All(s => s.SignalSource == first.SignalSource))
{
if (!_seenMessages.Contains(first.Transmission))
{
_seenMessages.Add(first.Transmission);
_transmitQueue.Enqueue(first.Transmission);
}
}
_receiveBuffer.Clear();
}
++_ticksFromLastReceivedBlock;
return;
}
_ticksFromLastReceivedBlock = 0;
if (signals.Count > 1 && signals[0].SignalStrength / signals[1].SignalStrength < _parameters.SnrCutoff)
{
return;
}
if (signals.Count != 0)
{
_receiveBuffer.Add(signals[0]);
return;
}
}
internal async Task ProcessJoinRequestAsync(LoRaRequest request)
{
LoRaDevice loRaDevice = null;
var loraRegion = request.Region;
try
{
var timeWatcher = request.GetTimeWatcher();
var processingTimeout = timeWatcher.GetRemainingTimeToJoinAcceptSecondWindow() - TimeSpan.FromMilliseconds(100);
using var joinAcceptCancellationToken = new CancellationTokenSource(processingTimeout > TimeSpan.Zero ? processingTimeout : TimeSpan.Zero);
var joinReq = (LoRaPayloadJoinRequest)request.Payload;
var devEui = joinReq.DevEUI;
using var scope = this.logger.BeginDeviceScope(devEui);
this.logger.LogInformation("join request received");
if (this.concentratorDeduplication.CheckDuplicateJoin(request) is ConcentratorDeduplicationResult.Duplicate)
{
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.DeduplicationDrop);
// we do not log here as the concentratorDeduplication service already does more detailed logging
return;
}
loRaDevice = await this.deviceRegistry.GetDeviceForJoinRequestAsync(devEui, joinReq.DevNonce);
if (loRaDevice == null)
{
request.NotifyFailed(devEui.ToString(), LoRaDeviceRequestFailedReason.UnknownDevice);
// we do not log here as we assume that the deviceRegistry does a more informed logging if returning null
return;
}
if (loRaDevice.AppKey is null)
{
this.logger.LogError("join refused: missing AppKey for OTAA device");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.InvalidJoinRequest);
return;
}
var appKey = loRaDevice.AppKey.Value;
this.joinRequestCounter?.Add(1);
if (loRaDevice.AppEui != joinReq.AppEui)
{
this.logger.LogError("join refused: AppEUI for OTAA does not match device");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.InvalidJoinRequest);
return;
}
if (!joinReq.CheckMic(appKey))
{
this.logger.LogError("join refused: invalid MIC");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.JoinMicCheckFailed);
return;
}
// Make sure that is a new request and not a replay
if (loRaDevice.DevNonce is { } devNonce&& devNonce == joinReq.DevNonce)
{
if (string.IsNullOrEmpty(loRaDevice.GatewayID))
{
this.logger.LogInformation("join refused: join already processed by another gateway");
}
else
{
this.logger.LogError("join refused: DevNonce already used by this device");
}
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.JoinDevNonceAlreadyUsed);
return;
}
// Check that the device is joining through the linked gateway and not another
if (!loRaDevice.IsOurDevice)
{
this.logger.LogInformation("join refused: trying to join not through its linked gateway, ignoring join request");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.HandledByAnotherGateway);
return;
}
var netId = this.configuration.NetId;
var appNonce = new AppNonce(RandomNumberGenerator.GetInt32(toExclusive: AppNonce.MaxValue + 1));
var appSKey = OTAAKeysGenerator.CalculateAppSessionKey(appNonce, netId, joinReq.DevNonce, appKey);
var nwkSKey = OTAAKeysGenerator.CalculateNetworkSessionKey(appNonce, netId, joinReq.DevNonce, appKey);
var address = RandomNumberGenerator.GetInt32(toExclusive: DevAddr.MaxNetworkAddress + 1);
// The 7 LBS of the NetID become the NwkID of a DevAddr:
var devAddr = new DevAddr(unchecked ((byte)netId.NetworkId), address);
var oldDevAddr = loRaDevice.DevAddr;
if (!timeWatcher.InTimeForJoinAccept())
{
this.receiveWindowMisses?.Add(1);
// in this case it's too late, we need to break and avoid saving twins
this.logger.LogInformation("join refused: processing of the join request took too long, sending no message");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.ReceiveWindowMissed);
return;
}
var updatedProperties = new LoRaDeviceJoinUpdateProperties
{
DevAddr = devAddr,
NwkSKey = nwkSKey,
AppSKey = appSKey,
AppNonce = appNonce,
DevNonce = joinReq.DevNonce,
NetId = netId,
Region = request.Region.LoRaRegion,
PreferredGatewayID = this.configuration.GatewayID,
};
if (loRaDevice.ClassType == LoRaDeviceClassType.C)
{
updatedProperties.SavePreferredGateway = true;
updatedProperties.SaveRegion = true;
updatedProperties.StationEui = request.StationEui;
}
DeviceJoinInfo deviceJoinInfo = null;
if (request.Region.LoRaRegion == LoRaRegionType.CN470RP2)
{
if (request.Region.TryGetJoinChannelIndex(request.RadioMetadata.Frequency, out var channelIndex))
{
updatedProperties.CN470JoinChannel = channelIndex;
deviceJoinInfo = new DeviceJoinInfo(channelIndex);
}
else
{
this.logger.LogError("failed to retrieve the join channel index for device");
}
}
var deviceUpdateSucceeded = await loRaDevice.UpdateAfterJoinAsync(updatedProperties, joinAcceptCancellationToken.Token);
if (!deviceUpdateSucceeded)
{
this.logger.LogError("join refused: join request could not save twin");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.IoTHubProblem);
return;
}
var windowToUse = timeWatcher.ResolveJoinAcceptWindowToUse();
if (windowToUse is null)
{
this.receiveWindowMisses?.Add(1);
this.logger.LogInformation("join refused: processing of the join request took too long, sending no message");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.ReceiveWindowMissed);
return;
}
this.deviceRegistry.UpdateDeviceAfterJoin(loRaDevice, oldDevAddr);
// Build join accept downlink message
// Build the DlSettings fields that is a superposition of RX2DR and RX1DROffset field
var dlSettings = new byte[1];
if (loRaDevice.DesiredRX2DataRate.HasValue)
{
if (request.Region.DRtoConfiguration.ContainsKey(loRaDevice.DesiredRX2DataRate.Value))
{
dlSettings[0] = (byte)((byte)loRaDevice.DesiredRX2DataRate & 0b00001111);
}
else
{
this.logger.LogError("twin RX2 DR value is not within acceptable values");
}
}
if (request.Region.IsValidRX1DROffset(loRaDevice.DesiredRX1DROffset))
{
var rx1droffset = (byte)(loRaDevice.DesiredRX1DROffset << 4);
dlSettings[0] = (byte)(dlSettings[0] + rx1droffset);
}
else
{
this.logger.LogError("twin RX1 offset DR value is not within acceptable values");
}
// The following DesiredRxDelay is different than the RxDelay to be passed to Serialize function
// This one is a delay between TX and RX for any message to be processed by joining device
// The field accepted by Serialize method is an indication of the delay (compared to receive time of join request)
// of when the message Join Accept message should be sent
var loraSpecDesiredRxDelay = RxDelay.RxDelay0;
if (Enum.IsDefined(loRaDevice.DesiredRXDelay))
{
loraSpecDesiredRxDelay = loRaDevice.DesiredRXDelay;
}
else
{
this.logger.LogError("twin RX delay value is not within acceptable values");
}
var loRaPayloadJoinAccept = new LoRaPayloadJoinAccept(
netId, // NETID 0 / 1 is default test
devAddr, // todo add device address management
appNonce,
dlSettings,
loraSpecDesiredRxDelay,
null);
if (!loraRegion.TryGetDownstreamChannelFrequency(request.RadioMetadata.Frequency, upstreamDataRate: request.RadioMetadata.DataRate, deviceJoinInfo: deviceJoinInfo, downstreamFrequency: out var freq))
{
this.logger.LogError("could not resolve DR and/or frequency for downstream");
request.NotifyFailed(loRaDevice, LoRaDeviceRequestFailedReason.InvalidUpstreamMessage);
return;
}
var joinAcceptBytes = loRaPayloadJoinAccept.Serialize(appKey);
var rx1 = windowToUse is not ReceiveWindow2
? new ReceiveWindow(loraRegion.GetDownstreamDataRate(request.RadioMetadata.DataRate, loRaDevice.ReportedRX1DROffset), freq)
: (ReceiveWindow?)null;
var rx2 = new ReceiveWindow(loraRegion.GetDownstreamRX2DataRate(this.configuration.Rx2DataRate, null, deviceJoinInfo, this.logger),
loraRegion.GetDownstreamRX2Freq(this.configuration.Rx2Frequency, deviceJoinInfo, this.logger));
var downlinkMessage = new DownlinkMessage(joinAcceptBytes,
request.RadioMetadata.UpInfo.Xtime,
rx1,
rx2,
loRaDevice.DevEUI,
loraRegion.JoinAcceptDelay1,
loRaDevice.ClassType,
request.StationEui,
request.RadioMetadata.UpInfo.AntennaPreference);
this.receiveWindowHits?.Add(1, KeyValuePair.Create(MetricRegistry.ReceiveWindowTagName, (object)windowToUse));
_ = request.DownstreamMessageSender.SendDownstreamAsync(downlinkMessage);
request.NotifySucceeded(loRaDevice, downlinkMessage);
if (this.logger.IsEnabled(LogLevel.Debug))
{
var jsonMsg = JsonConvert.SerializeObject(downlinkMessage);
this.logger.LogDebug($"{MacMessageType.JoinAccept} {jsonMsg}");
}
else
{
this.logger.LogInformation("join accepted");
}
}
catch (Exception ex) when
(ExceptionFilterUtility.True(() => this.logger.LogError(ex, $"failed to handle join request. {ex.Message}", LogLevel.Error),
() => this.unhandledExceptionCount?.Add(1)))
{
request.NotifyFailed(loRaDevice, ex);
throw;
}
}
/// <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));
}
