/// <summary>
/// Sends a message via UDP.
/// </summary>
/// <param name="handler">The handler to deal with the response message.</param>
/// <param name="tcsResponse">The TCS for the response message. (FutureResponse equivalent.)</param>
/// <param name="message">The message to send.</param>
/// <param name="channelCreator">The channel creator for the UDP channel.</param>
/// <param name="idleUdpSeconds">The idle time of a message until fail.</param>
/// <param name="broadcast">True, if the message is to be sent via layer 2 broadcast.</param>
/// <returns>The response message or null, if it is fire-and-forget or a failure occurred.</returns>
public async Task SendUdpAsync(IInboundHandler handler, TaskCompletionSource <Message.Message> tcsResponse, Message.Message message, ChannelCreator channelCreator, int idleUdpSeconds, bool broadcast)
{
// no need to continue if already finished
if (tcsResponse.Task.IsCompleted)
{
return;
}
RemovePeerIfFailed(tcsResponse, message);
bool isFireAndForget = handler == null;
// relay options
if (message.Sender.IsRelayed)
{
message.SetPeerSocketAddresses(message.Sender.PeerSocketAddresses);
IList <PeerSocketAddress> relayAddresses = new List <PeerSocketAddress>(message.Recipient.PeerSocketAddresses);
Logger.Debug("Send neighbor request to random relay peer {0}.", relayAddresses);
if (relayAddresses.Count > 0)
{
var relayAddress = relayAddresses[_random.NextInt(relayAddresses.Count)];
message.SetRecipientRelay(message.Recipient
.ChangePeerSocketAddress(relayAddress)
.ChangeIsRelayed(true));
}
else
{
const string msg = "Peer is relayed, but no relay is given.";
Logger.Error(msg);
tcsResponse.SetException(new TaskFailedException(msg));
return;
}
}
// check for invalid UDP connection to unreachable peers
if (message.Recipient.IsRelayed && message.Command != Rpc.Rpc.Commands.Neighbor.GetNr() &&
message.Command != Rpc.Rpc.Commands.Ping.GetNr())
{
string msg =
String.Format(
"Tried to send a UDP message to unreachable peers. Only TCP messages can be sent to unreachable peers: {0}.",
message);
Logger.Warn(msg);
tcsResponse.SetException(new TaskFailedException(msg));
return;
}
// pipeline handler setup
TimeoutFactory timeoutFactory = CreateTimeoutHandler(tcsResponse, idleUdpSeconds, isFireAndForget);
var handlers = new Dictionary <string, IChannelHandler>();
if (!isFireAndForget)
{
handlers.Add("timeout0", timeoutFactory.CreateIdleStateHandlerTomP2P());
handlers.Add("timeout1", timeoutFactory.CreateTimeHandler());
}
handlers.Add("decoder", new TomP2PSinglePacketUdp(ChannelClientConfiguration.SignatureFactory));
handlers.Add("encoder", new TomP2POutbound(false, ChannelClientConfiguration.SignatureFactory));
if (!isFireAndForget)
{
handlers.Add("handler", handler);
}
// create UDP channel
MyUdpClient udpClient = null;
try
{
udpClient = channelCreator.CreateUdp(broadcast, handlers);
}
catch (Exception ex)
{
string msg = "Channel creation failed. " + ex;
Logger.Debug(msg);
tcsResponse.SetException(ex);
// may have been closed by the other side
// or it may have been canceled from this side
}
// "afterConnect"
// check if channel could be created (due to shutdown)
if (udpClient == null)
{
const string msg = "Could not create a UDP socket. (Due to shutdown.)";
Logger.Warn(msg);
tcsResponse.SetException(new TaskFailedException(msg));
return;
}
Logger.Debug("About to connect to {0} with channel {1}, ff = {2}.", message.Recipient, udpClient, isFireAndForget);
// send request message
// processes client-side outbound pipeline
// (await for possible exception re-throw, does not block)
await udpClient.SendMessageAsync(message);
// if not fire-and-forget, receive response
if (isFireAndForget)
{
Logger.Debug("Fire and forget message {0} sent. Close channel {1} now.", message, udpClient);
tcsResponse.SetResult(null); // set FF result
}
else
{
// receive response message
// processes client-side inbound pipeline
await udpClient.ReceiveMessageAsync();
}
udpClient.Close();
}