internal static DiscoveryMessage CreateFromBytes(byte[] bytes)
{
GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
DiscoveryMessage result =
(DiscoveryMessage)Marshal.PtrToStructure(handle.AddrOfPinnedObject(),
typeof(DiscoveryMessage));
handle.Free();
return(result);
}
private void DiscoverRadio()
{
try
{
byte[] discoveryMessageBytes = { 0x38, 0x00, 0x5a, 0xa5 };
Array.Resize <byte>(ref discoveryMessageBytes, discoveryMessageBytes[0]);
var remoteEndPoint = new IPEndPoint(IPAddress.Broadcast, DISCOVERY_SERVER_PORT);
//send discovery message through all interfaces
//https://stackoverflow.com/questions/1096142
foreach (var intf in NetworkInterface.GetAllNetworkInterfaces())
{
if (intf.OperationalStatus == OperationalStatus.Up &&
intf.SupportsMulticast &&
intf.GetIPProperties().GetIPv4Properties() != null &&
NetworkInterface.LoopbackInterfaceIndex != intf.GetIPProperties().GetIPv4Properties().Index
)
{
foreach (var addr in intf.GetIPProperties().UnicastAddresses)
{
if (addr.Address.AddressFamily == AddressFamily.InterNetwork)
{
var localEndPoint = new IPEndPoint(addr.Address, DISCOVERY_CLIENT_PORT);
using (var udpClient = new UdpClient(localEndPoint))
{
udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);
udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontRoute, 1);
udpClient.Send(discoveryMessageBytes, discoveryMessageBytes.Length, remoteEndPoint);
}
}
}
}
}
//receive reply
var localEndpoint = new IPEndPoint(IPAddress.Any, DISCOVERY_CLIENT_PORT);
using (var udpClient = new UdpClient(localEndpoint))
{
udpClient.Client.ReceiveTimeout = 300;
var bytes = udpClient.Receive(ref remoteEndPoint);
discoveryMessage = DiscoveryMessage.CreateFromBytes(bytes);
}
//validate reply
if (discoveryMessage.Length != DISCOVERY_REPLY_SIZE ||
discoveryMessage.Key != DISCOVERY_SIGNATURE ||
discoveryMessage.Op != DISCOVERY_OP_RESP
)
{
throw (new Exception("invalid reply from the radio"));
}
if ((discoveryMessage.Status & (STATUS_BIT_CONNECTED | STATUS_BIT_RUNNING)) != 0)
{
throw (new Exception("radio already in use"));
}
}
catch (Exception e)
{
throw new Exception($"Afedri SDR not found.\n\n{e.Message}");
}
}
