//---------------------------------------------------------------------
// Constructor
//---------------------------------------------------------------------
public IPv6ToBleIPv6AddressCharacteristic(
GattLocalCharacteristic characteristic,
GenericGattService service,
IPAddress address
) : base(characteristic, service)
{
Ipv6Address = address;
Value = GattHelpers.ConvertByteArrayToBuffer(Ipv6Address.GetAddressBytes());
}
//---------------------------------------------------------------------
// Event handlers for advertisements
//---------------------------------------------------------------------
//
// Specifies behavior for when an advertisement is received by the
// watcher. Because the IPv6 Over Bluetooth Low Energy project is based
// on 6LoWPAN principles, routers actively watch for possible
// recipients when they have a packet to deliver. Receiving an
// advertisement means that there is a suitable node (or other router)
// within range that can receive the packet, so we transmit it here.
//
private async void OnAdvertisementReceived(
BluetoothLEAdvertisementWatcher watcher,
BluetoothLEAdvertisementReceivedEventArgs eventArgs
)
{
BluetoothError status = BluetoothError.Success;
// Variables for the remote device, the IPv6ToBle packet processing
// service, IPSS, and the device's characteristics
BluetoothLEDevice device = null;
GattDeviceService internetProtocolSupportService = null;
GattDeviceService ipv6ToBlePacketProcessingService = null;
IReadOnlyList <GattCharacteristic> deviceCharacteristics = null;
// Variables to hold the characteristics with which we need to
// interact
GattCharacteristic ipv6PacketWriteCharacteristic = null;
GattCharacteristic ipv6AddressCharacteristic = null;
IPAddress deviceAddress = null;
//
// Step 1
// Verify we have recevied a proper advertisement from the server
// by checking its manufacturer data. This is kind of redundant
// because we filter advertisements based on this, but it's not a
// bad idea.
//
IList <BluetoothLEManufacturerData> manufacturerDataList = eventArgs.Advertisement.ManufacturerData;
if (manufacturerDataList.Count == 0)
{
status = BluetoothError.OtherError;
Debug.WriteLine("No manufacturer data in the advertisement.");
goto Exit;
}
else
{
// There should only be one if it's one of our advertisements
BluetoothLEManufacturerData manufacturerData = manufacturerDataList[0];
// Verify it's the IPv6ToBle manufacturer name
string manufacturerDataCompanyId = string.Format("0x{0}",
manufacturerData.CompanyId.ToString("X")
);
if (manufacturerDataCompanyId != "0xDEDE")
{
status = BluetoothError.OtherError;
Debug.WriteLine("Manufacturer Company ID did not match " +
"IPv6ToBle."
);
goto Exit;
}
}
//
// Step 2
// Connect to the device
//
try
{
// Connect based on the device's Bluetooth address
device = await BluetoothLEDevice.FromBluetoothAddressAsync(eventArgs.BluetoothAddress);
if (device == null)
{
status = BluetoothError.DeviceNotConnected;
Debug.WriteLine("Error connecting to device.");
goto Exit;
}
} catch (Exception e) when(e.HResult == Constants.E_DEVICE_NOT_AVAILABLE)
{
status = BluetoothError.RadioNotAvailable;
Debug.WriteLine("Bluetooth radio is not on.");
goto Exit;
}
//
// Step 3
// Enumerate the GATT services to get the
// IPv6ToBlePacketProcessingService and Internet Protocol Support
// Service (IPSS)
//
if (device != null)
{
// Retrieve the list of services from the device (uncached)
GattDeviceServicesResult servicesResult = await device.GetGattServicesAsync(BluetoothCacheMode.Uncached);
if (servicesResult.Status == GattCommunicationStatus.Success)
{
var services = servicesResult.Services;
Debug.WriteLine($"Found {services.Count} services");
// Iterate through the list of services and check if
// both services we require are there
foreach (GattDeviceService service in services)
{
Guid uuid = service.Uuid;
// Check for IPv6ToBle Packet Write Service
if (uuid == Constants.IPv6ToBlePacketProcessingServiceUuid)
{
ipv6ToBlePacketProcessingService = service;
continue;
}
// Check for IPSS
ushort shortId = GattHelpers.ConvertUuidToShortId(uuid);
if (shortId == (ushort)GattHelpers.SigAssignedGattNativeUuid.InternetProtocolSupport)
{
internetProtocolSupportService = service;
continue;
}
}
}
}
// Report error if the device was not running our packet processing
// service for some reason
if (ipv6ToBlePacketProcessingService == null ||
internetProtocolSupportService == null)
{
status = BluetoothError.OtherError;
Debug.WriteLine("Device did not have the " +
"IPv6ToBlePacketProcessingService running or" +
" available, or did not have the Internet" +
" Protocol Support Service running or " +
"available."
);
goto Exit;
}
//
// Step 4
// Enumerate the GATT characteristics
//
try
{
// Verify we can access the service
DeviceAccessStatus accessStatus = await ipv6ToBlePacketProcessingService.RequestAccessAsync();
if (accessStatus == DeviceAccessStatus.Allowed)
{
// Enumerate the characteristics
GattCharacteristicsResult characteristicsResult =
await ipv6ToBlePacketProcessingService.GetCharacteristicsAsync(BluetoothCacheMode.Uncached);
if (characteristicsResult.Status == GattCommunicationStatus.Success)
{
deviceCharacteristics = characteristicsResult.Characteristics;
}
else
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not access the packet " +
"processing service."
);
goto Exit;
}
}
else
{
// Not granted access
status = BluetoothError.NotSupported;
Debug.WriteLine("Could not access the packet " +
"processing service."
);
goto Exit;
}
}
catch (Exception e)
{
status = BluetoothError.DeviceNotConnected;
Debug.WriteLine("Could not read characteristics due to " +
"permissions issues. " + e.Message
);
goto Exit;
}
if (deviceCharacteristics != null)
{
// Find the IPv6 Address and packet write characteristics
foreach (GattCharacteristic characteristic in deviceCharacteristics)
{
if (characteristic.Uuid == Constants.IPv6ToBleIPv6AddressCharacteristicUuid)
{
ipv6AddressCharacteristic = characteristic;
}
if (characteristic.Uuid == Constants.IPv6ToBlePacketWriteCharacteristicUuid)
{
ipv6PacketWriteCharacteristic = characteristic;
}
}
}
if (ipv6PacketWriteCharacteristic == null ||
ipv6AddressCharacteristic == null)
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not access the IPv6 address" +
" characteristic and the packet write" +
" characteristic.");
goto Exit;
}
// Get the device's IPv6 address from the characteristic
if (ipv6AddressCharacteristic != null)
{
GattReadResult readResult = await ipv6AddressCharacteristic.ReadValueAsync();
if (readResult.Status == GattCommunicationStatus.Success)
{
deviceAddress = new IPAddress(GattHelpers.ConvertBufferToByteArray(readResult.Value));
}
else
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not read the device's IPv6 address" +
" from the remote characteristic."
);
goto Exit;
}
}
//
// Step 5
// Write the packet now that we have verified that the device is
// supported and is either the destination or in the path to the
// destination
//
GattCommunicationStatus writeStatus =
await ipv6PacketWriteCharacteristic.WriteValueAsync(GattHelpers.ConvertByteArrayToBuffer(Packet));
if (writeStatus != GattCommunicationStatus.Success)
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not write the IPv6 packet to the" +
" remote device");
}
Exit:
if (status != BluetoothError.Success)
{
TransmittedSuccessfully = false;
}
else
{
TransmittedSuccessfully = true;
}
}
/// <summary>
/// Writes a packet to a given device.
/// </summary>
/// <param name="targetDevice">The target device.</param>
/// <param name="packet">The packet, compressed or not.</param>
/// <param name="compressedHeaderLength">Optional. The length of the compressed header if the caller is sending a compressed packet.</param>
/// <param name="payloadLength">Optional. The paylaod length of the packet. Only needed if the caller is sending a compressed packet.</param>
/// <returns></returns>
public static async Task <bool> WritePacketAsync(
DeviceInformation targetDevice,
byte[] packet,
int compressedHeaderLength,
int payloadLength
)
{
BluetoothError status = BluetoothError.Success;
// Variables for the remote device, the IPv6ToBle packet processing
// service, IPSS, and the device's characteristics
BluetoothLEDevice device = null;
GattDeviceService ipv6ToBlePacketProcessingService = null;
IReadOnlyList <GattCharacteristic> deviceCharacteristics = null;
// Variables for the remote packet write characteristic
GattCharacteristic ipv6PacketWriteCharacteristic = null;
GattCharacteristic compressedHeaderLengthCharacteristic = null;
GattCharacteristic payloadLengthCharacteristic = null;
// Variables for timing GATT communication latency and transmission time
Stopwatch gattLatencyTimer = new Stopwatch();
Stopwatch gattTransmissionTimer = new Stopwatch();
//
// Step 1
// Connect to the device
//
// Start timing how long it takes to perform pre-transmission GATT
// communications
gattLatencyTimer.Start();
try
{
// Connect based on the device's Bluetooth address
device = await BluetoothLEDevice.FromIdAsync(targetDevice.Id);
if (device == null)
{
status = BluetoothError.DeviceNotConnected;
Debug.WriteLine("Error connecting to device.");
goto Exit;
}
}
catch (Exception e) when(e.HResult == Constants.E_DEVICE_NOT_AVAILABLE)
{
status = BluetoothError.RadioNotAvailable;
Debug.WriteLine("Bluetooth radio is not on.");
goto Exit;
}
//
// Step 2
// Enumerate the GATT services to get the
// IPv6ToBlePacketProcessingService
//
if (device != null)
{
// Retrieve the list of services from the device (uncached)
GattDeviceServicesResult servicesResult = await device.GetGattServicesAsync(BluetoothCacheMode.Cached);
if (servicesResult.Status == GattCommunicationStatus.Success)
{
var services = servicesResult.Services;
Debug.WriteLine($"Found {services.Count} services when " +
"querying services for packet writing."
);
// Iterate through the list of services and check if
// both services we require are there
foreach (GattDeviceService service in services)
{
Guid uuid = service.Uuid;
// Check for IPv6ToBle Packet Write Service
if (uuid == Constants.IPv6ToBlePacketProcessingServiceUuid)
{
ipv6ToBlePacketProcessingService = service;
break;
}
}
}
}
// Report error if the device was not running our packet processing
// service for some reason
if (ipv6ToBlePacketProcessingService == null)
{
status = BluetoothError.OtherError;
Debug.WriteLine("Device did not have the " +
"IPv6ToBlePacketProcessingService running or" +
" available."
);
goto Exit;
}
//
// Step 3
// Enumerate the GATT characteristics
//
try
{
// Verify we can access the service
DeviceAccessStatus accessStatus = await ipv6ToBlePacketProcessingService.RequestAccessAsync();
if (accessStatus == DeviceAccessStatus.Allowed)
{
// Enumerate the characteristics
GattCharacteristicsResult characteristicsResult =
await ipv6ToBlePacketProcessingService.GetCharacteristicsAsync(BluetoothCacheMode.Cached);
if (characteristicsResult.Status == GattCommunicationStatus.Success)
{
deviceCharacteristics = characteristicsResult.Characteristics;
}
else
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not access the packet " +
"processing service."
);
goto Exit;
}
}
else
{
// Not granted access
status = BluetoothError.NotSupported;
Debug.WriteLine("Could not access the packet " +
"processing service."
);
goto Exit;
}
}
catch (Exception e)
{
status = BluetoothError.DeviceNotConnected;
Debug.WriteLine("Could not read characteristics due to " +
" permissions issues. " + e.Message
);
goto Exit;
}
// Find the required characteristics for packet writing
if (deviceCharacteristics != null)
{
foreach (GattCharacteristic characteristic in deviceCharacteristics)
{
if (characteristic.Uuid == Constants.IPv6ToBlePacketWriteCharacteristicUuid)
{
ipv6PacketWriteCharacteristic = characteristic;
}
if (characteristic.Uuid == Constants.IPv6ToBleCompressedHeaderLengthCharacteristicUuid)
{
compressedHeaderLengthCharacteristic = characteristic;
}
if (characteristic.Uuid == Constants.IPv6ToBlePayloadLengthCharacteristicUuid)
{
payloadLengthCharacteristic = characteristic;
}
}
}
if (ipv6PacketWriteCharacteristic == null ||
compressedHeaderLengthCharacteristic == null ||
payloadLengthCharacteristic == null)
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not access all three characteristics " +
"required for packet writing."
);
goto Exit;
}
// Stop the GATT latency timer now that we are ready to do the actual
// transmission
gattLatencyTimer.Stop();
Debug.WriteLine("GATT communications completed successfully. Total " +
$"time: {gattLatencyTimer.ElapsedMilliseconds} milliseconds."
);
//
// Step 5
// Write the packet now that we have verified that the device is
// supported and is either the destination or in the path to the
// destination
//
// Start the GATT transmission timer
gattTransmissionTimer.Start();
//DataWriter writer = new DataWriter();
//// Write the compressed header length
//writer.WriteInt32(compressedHeaderLength);
//GattCommunicationStatus writeStatus = await compressedHeaderLengthCharacteristic.WriteValueAsync(writer.DetachBuffer());
//if (writeStatus != GattCommunicationStatus.Success)
//{
// status = BluetoothError.OtherError;
// Debug.WriteLine("Could not write compressed header length.");
// goto Exit;
//}
//// Write the payload length
//writer = new DataWriter();
//writer.WriteInt32(payloadLength);
//writeStatus = await payloadLengthCharacteristic.WriteValueAsync(writer.DetachBuffer());
//if (writeStatus != GattCommunicationStatus.Success)
//{
// status = BluetoothError.OtherError;
// Debug.WriteLine("Could not write payload length.");
// goto Exit;
//}
// Write the packet itself last so the receiver knows that it has
// all needed data when this characteristic is written to
GattCommunicationStatus writeStatus = await ipv6PacketWriteCharacteristic.WriteValueAsync(GattHelpers.ConvertByteArrayToBuffer(packet),
GattWriteOption.WriteWithoutResponse
);
if (writeStatus != GattCommunicationStatus.Success)
{
status = BluetoothError.OtherError;
Debug.WriteLine("Could not write the IPv6 packet to the" +
" remote device");
goto Exit;
}
// Stop the GATT transmission timer and record the time if successful
gattTransmissionTimer.Stop();
long microseconds = gattTransmissionTimer.ElapsedTicks / (Stopwatch.Frequency / (1000L * 1000L));
Debug.WriteLine("GATT transmission completed successfully. Total " +
$"time: {microseconds} microseconds."
);
Exit:
// Dispose of the service and device that we accessed, then force
// a garbage collection to destroy the objects and fully disconnect
// from the remote GATT server and device. This is as a workaround
// for a current Windows bug that doesn't properly disconnect
// devices, as well as a workaround for the Broadcomm Bluetooth LE
// driver on the Raspberry Pi 3 that can't handle multiple connects
// and reconnects if it thinks it's still occupied.
//
// Additionally, at this step, if you had connected any events
// to the services or characteristics, you'd have to do that first.
// But we didn't do that here, so no need.
ipv6ToBlePacketProcessingService?.Dispose();
device?.Dispose();
device = null;
GC.Collect();
if (status != BluetoothError.Success)
{
// Stop the timers if we failed
if (gattLatencyTimer.IsRunning)
{
gattLatencyTimer.Stop();
}
if (gattTransmissionTimer.IsRunning)
{
gattTransmissionTimer.Stop();
}
return(false);
}
return(true);
}