public PHYPayload(byte[] packet, byte[] nwkSKey, byte[] appSKey, byte[] appKey, int fCntMsbSeed)
{
Packet = packet;
Mhdr = new MHDR(this);
switch (Mhdr.MessageType)
{
case MessageType.JoinRequest:
MacPayload = new JoinRequestMessage(this, appKey);
break;
case MessageType.JoinAccept:
MacPayload = new JoinAcceptMessage(this, appKey);
break;
case MessageType.Data:
MacPayload = new DataMessage(this, nwkSKey, appSKey, fCntMsbSeed);
break;
case MessageType.Proprietary:
throw new NotSupportedException();
default:
throw new NotSupportedException();
}
Mic = new MIC(this);
}
/// <summary>
///
/// </summary>
/// <param name="joinAcceptMessage"></param>
/// <param name="appKey"></param>
public CalculatedMIC(JoinAcceptMessage joinAcceptMessage, byte[] appKey)
{
if (appKey != null && appKey.Length == 16)
{
CryptoService crypto = new CryptoService();
// cmac = aes128_cmac(AppKey, MHDR | AppNonce | NetID | DevAddr | DLSettings | RxDelay | CFList)
// MIC = cmac[0..3]
byte[] data = new byte[joinAcceptMessage.RawData.Length + 1];
joinAcceptMessage.Parent.Mhdr.RawData.CopyTo(data.AsSpan()); // [1]
joinAcceptMessage.RawData.CopyTo(data.AsSpan(1));
byte[] fullCAMC = crypto.AESCMAC(appKey, data);
RawData = fullCAMC.AsSpan(0, 4).ToArray();
IsValid = true;
}
else
{
RawData = Array.Empty <byte>();
IsValid = false;
}
}
