/// <summary>
/// Serializes and pushes object to the queue with CRC calculation
/// </summary>
/// <param name="in_object">Object to push (must be Serializable)</param>
/// <returns>True if success, false if there is no space left in the queue</returns>
public bool Push(byte in_interface, object in_object)
{
int packet_index;
UInt16 crc;
// reserve storage for packet
packet_index = ReservePushBuffer();
if (packet_index == InvalidPacketIndex)
{
return(false);
}
// serialize packet
byte[] raw_packet_buffer = m_packets[packet_index].Buffer;
GCHandle handle = GCHandle.Alloc(raw_packet_buffer, GCHandleType.Pinned);
IntPtr buffer = handle.AddrOfPinnedObject();
Marshal.StructureToPtr(in_object, buffer, false);
handle.Free();
// update CRC
int raw_packet_size = Marshal.SizeOf(in_object);
crc = CRC16.CalculateForBlock(CRC16.InitValue, raw_packet_buffer, raw_packet_size);
raw_packet_buffer[raw_packet_size + 0] = ByteAccess.LowByte(crc);
raw_packet_buffer[raw_packet_size + 1] = ByteAccess.HighByte(crc);
// change buffer state
m_packets[packet_index].Interface = in_interface;
m_packets[packet_index].Length = (byte)(raw_packet_size + PacketConstants.PacketCRCLength);
m_packets[packet_index].Timestamp = DateTime.Now;
m_packets[packet_index].State = PacketBufferState.Valid;
return(true);
}
/// <summary>
/// Send packets over the opened socket (internal function only, no error checking, locking, etc. mechanism is implemented)
/// Only CRC is calculated before sending packet
/// </summary>
/// <param name="in_endpoint"></param>
/// <param name="in_packet"></param>
private void InternalPacketSend(EndPoint in_endpoint, byte[] in_packet)
{
// copy packet to the buffer
in_packet.CopyTo(m_transmit_buffer, 0);
// calculate and store CRC
UInt16 crc;
crc = CRC16.CalculateForBlock(CRC16.InitValue, in_packet, in_packet.Length);
m_transmit_buffer[in_packet.Length] = ByteAccess.LowByte(crc);
m_transmit_buffer[in_packet.Length + 1] = ByteAccess.HighByte(crc);
// send packet
m_client.BeginSendTo(m_transmit_buffer, 0, in_packet.Length + PacketConstants.PacketCRCLength, 0, in_endpoint, new AsyncCallback(SendCallback), this);
}
/// <summary>
/// Main thread function
/// </summary>
public void Run()
{
bool event_occured;
int i;
UInt16 crc;
AsyncCallback receiver_callback = new AsyncCallback(ReceiveCallback);
// create endpoints
m_receiver_endpoint = new IPEndPoint(IPAddress.Any, UDPLocalPort);
// init socket
m_timestamp = DateTime.MinValue;
m_client = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
m_client.Blocking = false;
m_client.EnableBroadcast = true;
m_client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
m_client.Bind(m_receiver_endpoint);
// init
m_upstream_bytes = 0;
m_downstream_bytes = 0;
// start data reception
m_client.BeginReceive(m_receive_buffer, 0, m_receive_buffer.Length, 0, receiver_callback, this);
// communication loop
while (!m_stop_requested)
{
// wait for event
event_occured = m_thread_event.WaitOne(ThreadWaitTimeout);
// exit loop if thread must be stopped
if (m_stop_requested)
{
break;
}
// process received data
if (m_received_data_length > 0)
{
if (m_received_data_length > 2)
{
// check CRC
crc = CRC16.CalculateForBlock(CRC16.InitValue, m_receive_buffer, m_received_data_length - 2);
if (ByteAccess.LowByte(crc) == m_receive_buffer[m_received_data_length - 2] && ByteAccess.HighByte(crc) == m_receive_buffer[m_received_data_length - 1])
{
// CRC OK -> continue processing received packet
PacketType type = (PacketType)m_receive_buffer[PacketConstants.TypeOffset];
// update statistics
Interlocked.Add(ref m_upstream_bytes, m_received_data_length);
// process received packet
switch (type)
{
// process device annnounce packet
case PacketType.CommDeviceAnnounce:
{
PacketDeviceAnnounce device_info;
// get announce packet
device_info = (PacketDeviceAnnounce)RawBinarySerialization.DeserializeObject(m_receive_buffer, typeof(PacketDeviceAnnounce));
// check if it is already on the list of active devices
DeviceInfo current_device_info = m_detected_devices.Find(x => x.UniqueID == device_info.UniqueID);
if (current_device_info != null)
{
// device is on the list
current_device_info.HostAnnouncePending = true;
current_device_info.LastInfoTimestamp = DateTime.Now;
}
else
{
DeviceInfo new_device = new DeviceInfo(device_info);
new_device.HostAnnouncePending = true;
if (new_device.Address != IPAddress.None)
{
m_detected_devices.Add(new_device);
if (m_detected_devices.Count == 1)
{
lock (m_detected_devices)
{
m_current_device = m_detected_devices[0];
}
}
}
}
}
break;
default:
// process received data
if (m_received_data_length <= PacketConstants.PacketMaxLength)
{
m_communication_manager.StoreReceivedPacket(m_communication_channel_index, m_receive_buffer, (byte)m_received_data_length);
}
break;
}
}
}
// restart reception
try
{
m_received_data_length = 0;
m_client.BeginReceive(m_receive_buffer, 0, m_receive_buffer.Length, 0, receiver_callback, this);
}
catch
{
// TODO: error handling
}
}
// send host announce for devices
for (i = 0; i < m_detected_devices.Count; i++)
{
IPAddress address_mask = new IPAddress(new byte[] { 255, 255, 255, 0 });
if (m_detected_devices[i].HostAnnouncePending)
{
IPAddress local_ip = GetLocalIPAddress(m_detected_devices[i].Address, address_mask);
if (m_sender_lock.Wait(0))
{
// create host info packet
PacketHostAnnounce info = new PacketHostAnnounce();
info.Address = (uint)IPAddress.NetworkToHostOrder(BitConverter.ToInt32(local_ip.GetAddressBytes(), 0));
byte[] packet = RawBinarySerialization.SerializeObject(info);
// send host info packet
EndPoint transmitter_endpoint = new IPEndPoint(m_detected_devices[i].Address, UDPRemotePort);
InternalPacketSend(transmitter_endpoint, packet);
m_detected_devices[i].HostAnnouncePending = false;
}
}
}
// delete unreachable or connectecd devices from the list
DateTime current_timestamp = DateTime.Now;
i = 0;
while (i < m_detected_devices.Count)
{
// if devlice is silent for a while -> remove from the list
if ((current_timestamp - m_detected_devices[i].LastInfoTimestamp).TotalMilliseconds > DeviceAnnounceTimeout)
{
m_detected_devices.RemoveAt(i);
}
else
{
i++;
}
}
}
// close socket
m_client.Shutdown(SocketShutdown.Both);
Thread.Sleep(10);
m_client.Close();
// thread is finished
m_thread_stopped.Set();
}
/// <summary>
/// Main thread function
/// </summary>
public void Run()
{
bool event_occured;
UInt16 crc;
int received_data_pos;
int received_packet_pos;
// init SLIPs
m_receiver_slip.ResetDecoder();
try
{
m_serial_port = new SerialPort(PortName, BaudRate, Parity.None, 8, StopBits.One);
m_serial_port.ReadTimeout = 50;
m_serial_port.WriteTimeout = 50;
m_serial_port.ReadBufferSize = 4096;
m_serial_port.Open();
}
catch
{
return;
}
// init
m_upstream_bytes = 0;
m_downstream_bytes = 0;
received_data_pos = 0;
received_packet_pos = 0;
// start data reception
m_read_pending = true;
m_serial_port.BaseStream.BeginRead(m_receive_data_buffer, 0, m_receive_data_buffer.Length, m_receiver_callback, this);
// communication loop
while (!m_stop_requested)
{
// wait for event
event_occured = m_thread_event.WaitOne(ThreadWaitTimeout);
// exit loop if thread must be stopped
if (m_stop_requested)
{
break;
}
// process received data
if (m_received_data_length > 0)
{
received_data_pos = 0;
while (received_data_pos < m_received_data_length)
{
// SLIP decode data
if (m_receiver_slip.DecodeBlock(m_receive_data_buffer, ref received_data_pos, m_received_data_length, m_receive_packet_buffer, ref received_packet_pos))
{
// packet decoded -> check CRC
if (received_packet_pos > (Marshal.SizeOf(typeof(PacketBase)) + PacketConstants.PacketCRCLength))
{
m_received_packet_length = received_packet_pos;
crc = CRC16.CalculateForBlock(CRC16.InitValue, m_receive_packet_buffer, m_received_packet_length - PacketConstants.PacketCRCLength);
if (ByteAccess.LowByte(crc) == m_receive_packet_buffer[m_received_packet_length - 2] && ByteAccess.HighByte(crc) == m_receive_packet_buffer[m_received_packet_length - 1])
{
// CRC OK -> continue processing received packet
PacketType type = (PacketType)m_receive_data_buffer[PacketConstants.TypeOffset];
// update statistics
Interlocked.Add(ref m_upstream_bytes, m_received_data_length);
// process received data
if (m_received_packet_length <= PacketConstants.PacketMaxLength)
{
m_communication_manager.StoreReceivedPacket(m_communication_channel_index, m_receive_packet_buffer, (byte)m_received_packet_length);
}
}
}
// restart packet decoding
received_packet_pos = 0;
}
m_read_pending = false;
}
}
// restart reception
if (!m_read_pending)
{
try
{
m_received_data_length = 0;
m_read_pending = true;
m_serial_port.BaseStream.BeginRead(m_receive_data_buffer, 0, m_receive_data_buffer.Length, m_receiver_callback, this);
}
catch
{
// stop thread because of the unexpected error
m_stop_requested = true;
m_thread_event.Set();
}
}
}
// close socket
m_serial_port.Close();
m_serial_port = null;
// thread is finished
m_thread_stopped.Set();
}
