// Bytes returns the bytes
func (m *Message) Bytes() []byte {
if m.FPort == 0 {
m.FPort = 1
}
macPayload := &lorawan.MACPayload{}
macPayload.FHDR = lorawan.FHDR{
DevAddr: lorawan.DevAddr(m.devAddr),
FCnt: uint32(m.FCnt),
}
macPayload.FPort = pointer.Uint8(uint8(m.FPort))
macPayload.FRMPayload = []lorawan.Payload{&lorawan.DataPayload{Bytes: m.Payload}}
phyPayload := &lorawan.PHYPayload{}
phyPayload.MHDR = lorawan.MHDR{
MType: lorawan.UnconfirmedDataUp,
Major: lorawan.LoRaWANR1,
}
if m.confirmed {
phyPayload.MHDR.MType = lorawan.ConfirmedDataUp
}
phyPayload.MACPayload = macPayload
phyPayload.EncryptFRMPayload(lorawan.AES128Key(m.appSKey))
phyPayload.SetMIC(lorawan.AES128Key(m.nwkSKey))
uplinkBytes, _ := phyPayload.MarshalBinary()
return uplinkBytes
}
func (h *handler) ConvertToLoRaWAN(ctx log.Interface, appDown *types.DownlinkMessage, ttnDown *pb_broker.DownlinkMessage) error {
// Find Device
dev, err := h.devices.Get(appDown.AppID, appDown.DevID)
if err != nil {
return err
}
// LoRaWAN: Unmarshal Downlink
var phyPayload lorawan.PHYPayload
err = phyPayload.UnmarshalBinary(ttnDown.Payload)
if err != nil {
return err
}
macPayload, ok := phyPayload.MACPayload.(*lorawan.MACPayload)
if !ok {
return errors.NewErrInvalidArgument("Downlink", "does not contain a MAC payload")
}
if ttnDown.DownlinkOption != nil && ttnDown.DownlinkOption.ProtocolConfig.GetLorawan() != nil {
macPayload.FHDR.FCnt = ttnDown.DownlinkOption.ProtocolConfig.GetLorawan().FCnt
}
// Abort when downlink not needed
if len(appDown.PayloadRaw) == 0 && !macPayload.FHDR.FCtrl.ACK && len(macPayload.FHDR.FOpts) == 0 {
return ErrNotNeeded
}
// Set FPort
if appDown.FPort != 0 {
macPayload.FPort = &appDown.FPort
}
// Set Payload
if len(appDown.PayloadRaw) > 0 {
macPayload.FRMPayload = []lorawan.Payload{&lorawan.DataPayload{Bytes: appDown.PayloadRaw}}
if macPayload.FPort == nil || *macPayload.FPort == 0 {
macPayload.FPort = pointer.Uint8(1)
}
} else {
macPayload.FRMPayload = []lorawan.Payload{}
}
// Encrypt
err = phyPayload.EncryptFRMPayload(lorawan.AES128Key(dev.AppSKey))
if err != nil {
return err
}
// Set MIC
err = phyPayload.SetMIC(lorawan.AES128Key(dev.NwkSKey))
if err != nil {
return err
}
// Marshal
phyPayloadBytes, err := phyPayload.MarshalBinary()
if err != nil {
return err
}
ttnDown.Payload = phyPayloadBytes
return nil
}