func (h *handler) ConvertFromLoRaWAN(ctx log.Interface, ttnUp *pb_broker.DeduplicatedUplinkMessage, appUp *types.UplinkMessage) error {
// Find Device
dev, err := h.devices.Get(ttnUp.AppId, ttnUp.DevId)
if err != nil {
return err
}
// Check for LoRaWAN
if lorawan := ttnUp.ProtocolMetadata.GetLorawan(); lorawan == nil {
return errors.NewErrInvalidArgument("Activation", "does not contain LoRaWAN metadata")
}
// LoRaWAN: Unmarshal Uplink
var phyPayload lorawan.PHYPayload
err = phyPayload.UnmarshalBinary(ttnUp.Payload)
if err != nil {
return err
}
macPayload, ok := phyPayload.MACPayload.(*lorawan.MACPayload)
if !ok {
return errors.NewErrInvalidArgument("Uplink", "does not contain a MAC payload")
}
macPayload.FHDR.FCnt = ttnUp.ProtocolMetadata.GetLorawan().FCnt
appUp.FCnt = macPayload.FHDR.FCnt
ctx = ctx.WithField("FCnt", appUp.FCnt)
// LoRaWAN: Validate MIC
ok, err = phyPayload.ValidateMIC(lorawan.AES128Key(dev.NwkSKey))
if err != nil {
return err
}
if !ok {
return errors.NewErrNotFound("device that validates MIC")
}
// LoRaWAN: Decrypt
if macPayload.FPort != nil && *macPayload.FPort != 0 && len(macPayload.FRMPayload) == 1 {
appUp.FPort = *macPayload.FPort
ctx = ctx.WithField("FCnt", appUp.FPort)
if err := phyPayload.DecryptFRMPayload(lorawan.AES128Key(dev.AppSKey)); err != nil {
return errors.NewErrInternal("Could not decrypt payload")
}
if len(macPayload.FRMPayload) == 1 {
payload, ok := macPayload.FRMPayload[0].(*lorawan.DataPayload)
if !ok {
return errors.NewErrInvalidArgument("Uplink FRMPayload", "must be of type *lorawan.DataPayload")
}
appUp.PayloadRaw = payload.Bytes
}
}
// LoRaWAN: Publish ACKs as events
if macPayload.FHDR.FCtrl.ACK {
h.mqttEvent <- &types.DeviceEvent{
AppID: appUp.AppID,
DevID: appUp.DevID,
Event: types.DownlinkAckEvent,
}
}
return nil
}