/// <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));
}
}