/// <summary>
/// Find a SmartSocketServer on the local network using UDP broadcast. This will block
/// waiting for a server to respond or until you cancel using the CancellationToken.
/// </summary>
/// <returns>The connected client or null if task is cancelled.</returns>
public static async Task <SmartSocketClient> FindServerAsync(string serviceName, string clientName, SmartSocketTypeResolver resolver, CancellationToken token,
string udpGroupAddress = "226.10.10.2", int udpGroupPort = 37992)
{
return(await Task.Run(async() =>
{
string localHost = FindLocalHostName();
if (localHost == null)
{
return null;
}
while (!token.IsCancellationRequested)
{
try
{
var groupAddr = IPAddress.Parse(udpGroupAddress);
IPEndPoint remoteEP = new IPEndPoint(groupAddr, udpGroupPort);
UdpClient udpClient = new UdpClient(0);
MemoryStream ms = new MemoryStream();
BinaryWriter writer = new BinaryWriter(ms);
writer.Write(serviceName.Length);
writer.Write(serviceName);
byte[] bytes = ms.ToArray();
udpClient.Send(bytes, bytes.Length, remoteEP);
CancellationTokenSource receiveTaskSource = new CancellationTokenSource();
Task <UdpReceiveResult> receiveTask = udpClient.ReceiveAsync();
if (receiveTask.Wait(5000, receiveTaskSource.Token))
{
UdpReceiveResult result = receiveTask.Result;
IPEndPoint serverEP = result.RemoteEndPoint;
byte[] buffer = result.Buffer;
BinaryReader reader = new BinaryReader(new MemoryStream(buffer));
int len = reader.ReadInt32();
string addr = reader.ReadString();
string[] parts = addr.Split(':');
if (parts.Length == 2)
{
var a = IPAddress.Parse(parts[0]);
SmartSocketClient client = await ConnectAsync(new IPEndPoint(a, int.Parse(parts[1])), clientName, resolver);
if (client != null)
{
client.ServerName = serviceName;
client.Name = localHost;
return client;
}
}
}
else
{
receiveTaskSource.Cancel();
}
}
catch (Exception ex)
{
Debug.WriteLine("Something went wrong with Udp connection: " + ex.Message);
}
}
return null;
}));
}
internal void RemoveClient(SmartSocketClient client)
{
bool found = false;
lock (this.clients)
{
found = this.clients.Contains(client);
this.clients.Remove(client);
}
if (found && this.ClientDisconnected != null)
{
this.ClientDisconnected(this, client);
}
}
internal static async Task <SmartSocketClient> ConnectAsync(IPEndPoint serverEP, string clientName, SmartSocketTypeResolver resolver)
{
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
bool connected = false;
CancellationTokenSource src = new CancellationTokenSource();
try
{
Task task = Task.Run(() =>
{
try
{
client.Connect(serverEP);
connected = true;
}
catch (Exception e)
{
Debug.WriteLine("Connect exception: " + e.Message);
}
}, src.Token);
// give it 30 seconds to connect...
if (!task.Wait(60000))
{
src.Cancel();
}
}
catch (TaskCanceledException)
{
// move on...
}
if (connected)
{
var result = new SmartSocketClient(null, client, resolver)
{
Name = clientName,
ServerName = GetHostName(serverEP.Address)
};
SocketMessage response = await result.SendReceiveAsync(new SocketMessage(ConnectedMessageId, clientName));
return(result);
}
return(null);
}
internal async Task <bool> OpenBackChannel(SmartSocketClient client, int port)
{
if (BackChannelOpened != null)
{
IPEndPoint ipe = (IPEndPoint)(client.Socket.RemoteEndPoint);
IPEndPoint endPoint = new IPEndPoint(ipe.Address, port);
SmartSocketClient channel = await SmartSocketClient.ConnectAsync(endPoint, this.serviceName, this.resolver);
client.BackChannel = channel;
this.BackChannelOpened(this, client);
return(true);
}
else
{
// server is not expecting a backchannel!
return(false);
}
}
private void OnAccept(Socket client)
{
IPEndPoint ep1 = client.RemoteEndPoint as IPEndPoint;
SmartSocketClient proxy = new SmartSocketClient(this, client, this.resolver)
{
Name = ep1.ToString(),
ServerName = SmartSocketClient.FindLocalHostName()
};
proxy.Disconnected += this.OnClientDisconnected;
SmartSocketClient[] snapshot = null;
lock (this.clients)
{
snapshot = this.clients.ToArray();
}
foreach (SmartSocketClient s in snapshot)
{
IPEndPoint ep2 = s.Socket.RemoteEndPoint as IPEndPoint;
if (ep1 == ep2)
{
// can only have one client using this end point.
this.RemoveClient(s);
}
}
lock (this.clients)
{
this.clients.Add(proxy);
}
if (this.ClientConnected != null)
{
this.ClientConnected(this, proxy);
}
}
private void UdpListenerThread()
{
var localHost = SmartSocketClient.FindLocalHostName();
List <string> addresses = SmartSocketClient.FindLocalIpAddresses();
if (localHost == null || addresses.Count == 0)
{
return; // no network.
}
IPEndPoint remoteEP = new IPEndPoint(GroupAddress, GroupPort);
this.udpListener = new UdpClient(GroupPort);
this.udpListener.JoinMulticastGroup(GroupAddress);
while (true)
{
byte[] data = this.udpListener.Receive(ref remoteEP);
if (data != null)
{
BinaryReader reader = new BinaryReader(new MemoryStream(data));
int len = reader.ReadInt32();
string msg = reader.ReadString();
if (msg == this.serviceName)
{
// send response back with info on how to connect to this server.
IPEndPoint localEp = (IPEndPoint)this.listener.LocalEndPoint;
string addr = localEp.ToString();
MemoryStream ms = new MemoryStream();
BinaryWriter writer = new BinaryWriter(ms);
writer.Write(addr.Length);
writer.Write(addr);
writer.Flush();
byte[] buffer = ms.ToArray();
this.udpListener.Send(buffer, buffer.Length, remoteEP);
}
}
}
}
private void OnClientDisconnected(object sender, EventArgs e)
{
SmartSocketClient client = (SmartSocketClient)sender;
this.RemoveClient(client);
}