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TcpServer.cs
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TcpServer.cs
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using System;
using System.Collections.Concurrent;
using System.Diagnostics;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
namespace NetCoreServer
{
/// <summary>
/// TCP server is used to connect, disconnect and manage TCP sessions
/// </summary>
/// <remarks>Thread-safe</remarks>
public class TcpServer : IDisposable
{
/// <summary>
/// Initialize TCP server with a given IP address and port number
/// </summary>
/// <param name="address">IP address</param>
/// <param name="port">Port number</param>
public TcpServer(IPAddress address, int port) : this(new IPEndPoint(address, port)) {}
/// <summary>
/// Initialize TCP server with a given IP address and port number
/// </summary>
/// <param name="address">IP address</param>
/// <param name="port">Port number</param>
public TcpServer(string address, int port) : this(new IPEndPoint(IPAddress.Parse(address), port)) {}
/// <summary>
/// Initialize TCP server with a given DNS endpoint
/// </summary>
/// <param name="endpoint">DNS endpoint</param>
public TcpServer(DnsEndPoint endpoint) : this(endpoint as EndPoint, endpoint.Host, endpoint.Port) {}
/// <summary>
/// Initialize TCP server with a given IP endpoint
/// </summary>
/// <param name="endpoint">IP endpoint</param>
public TcpServer(IPEndPoint endpoint) : this(endpoint as EndPoint, endpoint.Address.ToString(), endpoint.Port) {}
/// <summary>
/// Initialize TCP server with a given endpoint, address and port
/// </summary>
/// <param name="endpoint">Endpoint</param>
/// <param name="address">Server address</param>
/// <param name="port">Server port</param>
private TcpServer(EndPoint endpoint, string address, int port)
{
Id = Guid.NewGuid();
Address = address;
Port = port;
Endpoint = endpoint;
}
/// <summary>
/// Server Id
/// </summary>
public Guid Id { get; }
/// <summary>
/// TCP server address
/// </summary>
public string Address { get; }
/// <summary>
/// TCP server port
/// </summary>
public int Port { get; }
/// <summary>
/// Endpoint
/// </summary>
public EndPoint Endpoint { get; private set; }
/// <summary>
/// Number of sessions connected to the server
/// </summary>
public long ConnectedSessions { get { return Sessions.Count; } }
/// <summary>
/// Number of bytes pending sent by the server
/// </summary>
public long BytesPending { get { return _bytesPending; } }
/// <summary>
/// Number of bytes sent by the server
/// </summary>
public long BytesSent { get { return _bytesSent; } }
/// <summary>
/// Number of bytes received by the server
/// </summary>
public long BytesReceived { get { return _bytesReceived; } }
/// <summary>
/// Option: acceptor backlog size
/// </summary>
/// <remarks>
/// This option will set the listening socket's backlog size
/// </remarks>
public int OptionAcceptorBacklog { get; set; } = 1024;
/// <summary>
/// Option: dual mode socket
/// </summary>
/// <remarks>
/// Specifies whether the Socket is a dual-mode socket used for both IPv4 and IPv6.
/// Will work only if socket is bound on IPv6 address.
/// </remarks>
public bool OptionDualMode { get; set; }
/// <summary>
/// Option: keep alive
/// </summary>
/// <remarks>
/// This option will setup SO_KEEPALIVE if the OS support this feature
/// </remarks>
public bool OptionKeepAlive { get; set; }
/// <summary>
/// Option: TCP keep alive time
/// </summary>
/// <remarks>
/// The number of seconds a TCP connection will remain alive/idle before keepalive probes are sent to the remote
/// </remarks>
public int OptionTcpKeepAliveTime { get; set; } = -1;
/// <summary>
/// Option: TCP keep alive interval
/// </summary>
/// <remarks>
/// The number of seconds a TCP connection will wait for a keepalive response before sending another keepalive probe
/// </remarks>
public int OptionTcpKeepAliveInterval { get; set; } = -1;
/// <summary>
/// Option: TCP keep alive retry count
/// </summary>
/// <remarks>
/// The number of TCP keep alive probes that will be sent before the connection is terminated
/// </remarks>
public int OptionTcpKeepAliveRetryCount { get; set; } = -1;
/// <summary>
/// Option: no delay
/// </summary>
/// <remarks>
/// This option will enable/disable Nagle's algorithm for TCP protocol
/// </remarks>
public bool OptionNoDelay { get; set; }
/// <summary>
/// Option: reuse address
/// </summary>
/// <remarks>
/// This option will enable/disable SO_REUSEADDR if the OS support this feature
/// </remarks>
public bool OptionReuseAddress { get; set; }
/// <summary>
/// Option: enables a socket to be bound for exclusive access
/// </summary>
/// <remarks>
/// This option will enable/disable SO_EXCLUSIVEADDRUSE if the OS support this feature
/// </remarks>
public bool OptionExclusiveAddressUse { get; set; }
/// <summary>
/// Option: receive buffer size
/// </summary>
public int OptionReceiveBufferSize { get; set; } = 8192;
/// <summary>
/// Option: send buffer size
/// </summary>
public int OptionSendBufferSize { get; set; } = 8192;
#region Start/Stop server
// Server acceptor
private Socket _acceptorSocket;
private SocketAsyncEventArgs _acceptorEventArg;
// Server statistic
internal long _bytesPending;
internal long _bytesSent;
internal long _bytesReceived;
/// <summary>
/// Is the server started?
/// </summary>
public bool IsStarted { get; private set; }
/// <summary>
/// Is the server accepting new clients?
/// </summary>
public bool IsAccepting { get; private set; }
/// <summary>
/// Create a new socket object
/// </summary>
/// <remarks>
/// Method may be override if you need to prepare some specific socket object in your implementation.
/// </remarks>
/// <returns>Socket object</returns>
protected virtual Socket CreateSocket()
{
return new Socket(Endpoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
}
/// <summary>
/// Start the server
/// </summary>
/// <returns>'true' if the server was successfully started, 'false' if the server failed to start</returns>
public virtual bool Start()
{
Debug.Assert(!IsStarted, "TCP server is already started!");
if (IsStarted)
return false;
// Setup acceptor event arg
_acceptorEventArg = new SocketAsyncEventArgs();
_acceptorEventArg.Completed += OnAsyncCompleted;
// Create a new acceptor socket
_acceptorSocket = CreateSocket();
// Update the acceptor socket disposed flag
IsSocketDisposed = false;
// Apply the option: reuse address
_acceptorSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, OptionReuseAddress);
// Apply the option: exclusive address use
_acceptorSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ExclusiveAddressUse, OptionExclusiveAddressUse);
// Apply the option: dual mode (this option must be applied before listening)
if (_acceptorSocket.AddressFamily == AddressFamily.InterNetworkV6)
_acceptorSocket.DualMode = OptionDualMode;
// Bind the acceptor socket to the endpoint
_acceptorSocket.Bind(Endpoint);
// Refresh the endpoint property based on the actual endpoint created
Endpoint = _acceptorSocket.LocalEndPoint;
// Call the server starting handler
OnStarting();
// Start listen to the acceptor socket with the given accepting backlog size
_acceptorSocket.Listen(OptionAcceptorBacklog);
// Reset statistic
_bytesPending = 0;
_bytesSent = 0;
_bytesReceived = 0;
// Update the started flag
IsStarted = true;
// Call the server started handler
OnStarted();
// Perform the first server accept
IsAccepting = true;
StartAccept(_acceptorEventArg);
return true;
}
/// <summary>
/// Stop the server
/// </summary>
/// <returns>'true' if the server was successfully stopped, 'false' if the server is already stopped</returns>
public virtual bool Stop()
{
Debug.Assert(IsStarted, "TCP server is not started!");
if (!IsStarted)
return false;
// Stop accepting new clients
IsAccepting = false;
// Reset acceptor event arg
_acceptorEventArg.Completed -= OnAsyncCompleted;
// Call the server stopping handler
OnStopping();
try
{
// Close the acceptor socket
_acceptorSocket.Close();
// Dispose the acceptor socket
_acceptorSocket.Dispose();
// Dispose event arguments
_acceptorEventArg.Dispose();
// Update the acceptor socket disposed flag
IsSocketDisposed = true;
}
catch (ObjectDisposedException) {}
// Disconnect all sessions
DisconnectAll();
// Update the started flag
IsStarted = false;
// Call the server stopped handler
OnStopped();
return true;
}
/// <summary>
/// Restart the server
/// </summary>
/// <returns>'true' if the server was successfully restarted, 'false' if the server failed to restart</returns>
public virtual bool Restart()
{
if (!Stop())
return false;
while (IsStarted)
Thread.Yield();
return Start();
}
#endregion
#region Accepting clients
/// <summary>
/// Start accept a new client connection
/// </summary>
private void StartAccept(SocketAsyncEventArgs e)
{
// Socket must be cleared since the context object is being reused
e.AcceptSocket = null;
// Async accept a new client connection
if (!_acceptorSocket.AcceptAsync(e))
ProcessAccept(e);
}
/// <summary>
/// Process accepted client connection
/// </summary>
private void ProcessAccept(SocketAsyncEventArgs e)
{
if (e.SocketError == SocketError.Success)
{
// Create a new session to register
var session = CreateSession();
// Register the session
RegisterSession(session);
// Connect new session
session.Connect(e.AcceptSocket);
}
else
SendError(e.SocketError);
// Accept the next client connection
if (IsAccepting)
StartAccept(e);
}
/// <summary>
/// This method is the callback method associated with Socket.AcceptAsync()
/// operations and is invoked when an accept operation is complete
/// </summary>
private void OnAsyncCompleted(object sender, SocketAsyncEventArgs e)
{
if (IsSocketDisposed)
return;
ProcessAccept(e);
}
#endregion
#region Session factory
/// <summary>
/// Create TCP session factory method
/// </summary>
/// <returns>TCP session</returns>
protected virtual TcpSession CreateSession() { return new TcpSession(this); }
#endregion
#region Session management
/// <summary>
/// Server sessions
/// </summary>
protected readonly ConcurrentDictionary<Guid, TcpSession> Sessions = new ConcurrentDictionary<Guid, TcpSession>();
/// <summary>
/// Disconnect all connected sessions
/// </summary>
/// <returns>'true' if all sessions were successfully disconnected, 'false' if the server is not started</returns>
public virtual bool DisconnectAll()
{
if (!IsStarted)
return false;
// Disconnect all sessions
foreach (var session in Sessions.Values)
session.Disconnect();
return true;
}
/// <summary>
/// Find a session with a given Id
/// </summary>
/// <param name="id">Session Id</param>
/// <returns>Session with a given Id or null if the session it not connected</returns>
public TcpSession FindSession(Guid id)
{
// Try to find the required session
return Sessions.TryGetValue(id, out TcpSession result) ? result : null;
}
/// <summary>
/// Register a new session
/// </summary>
/// <param name="session">Session to register</param>
internal void RegisterSession(TcpSession session)
{
// Register a new session
Sessions.TryAdd(session.Id, session);
}
/// <summary>
/// Unregister session by Id
/// </summary>
/// <param name="id">Session Id</param>
internal void UnregisterSession(Guid id)
{
// Unregister session by Id
Sessions.TryRemove(id, out TcpSession _);
}
#endregion
#region Multicasting
/// <summary>
/// Multicast data to all connected sessions
/// </summary>
/// <param name="buffer">Buffer to multicast</param>
/// <returns>'true' if the data was successfully multicasted, 'false' if the data was not multicasted</returns>
public virtual bool Multicast(byte[] buffer) => Multicast(buffer.AsSpan());
/// <summary>
/// Multicast data to all connected clients
/// </summary>
/// <param name="buffer">Buffer to multicast</param>
/// <param name="offset">Buffer offset</param>
/// <param name="size">Buffer size</param>
/// <returns>'true' if the data was successfully multicasted, 'false' if the data was not multicasted</returns>
public virtual bool Multicast(byte[] buffer, long offset, long size) => Multicast(buffer.AsSpan((int)offset, (int)size));
/// <summary>
/// Multicast data to all connected clients
/// </summary>
/// <param name="buffer">Buffer to send as a span of bytes</param>
/// <returns>'true' if the data was successfully multicasted, 'false' if the data was not multicasted</returns>
public virtual bool Multicast(ReadOnlySpan<byte> buffer)
{
if (!IsStarted)
return false;
if (buffer.IsEmpty)
return true;
// Multicast data to all sessions
foreach (var session in Sessions.Values)
session.SendAsync(buffer);
return true;
}
/// <summary>
/// Multicast text to all connected clients
/// </summary>
/// <param name="text">Text string to multicast</param>
/// <returns>'true' if the text was successfully multicasted, 'false' if the text was not multicasted</returns>
public virtual bool Multicast(string text) => Multicast(Encoding.UTF8.GetBytes(text));
/// <summary>
/// Multicast text to all connected clients
/// </summary>
/// <param name="text">Text to multicast as a span of characters</param>
/// <returns>'true' if the text was successfully multicasted, 'false' if the text was not multicasted</returns>
public virtual bool Multicast(ReadOnlySpan<char> text) => Multicast(Encoding.UTF8.GetBytes(text.ToArray()));
#endregion
#region Server handlers
/// <summary>
/// Handle server starting notification
/// </summary>
protected virtual void OnStarting() {}
/// <summary>
/// Handle server started notification
/// </summary>
protected virtual void OnStarted() {}
/// <summary>
/// Handle server stopping notification
/// </summary>
protected virtual void OnStopping() {}
/// <summary>
/// Handle server stopped notification
/// </summary>
protected virtual void OnStopped() {}
/// <summary>
/// Handle session connecting notification
/// </summary>
/// <param name="session">Connecting session</param>
protected virtual void OnConnecting(TcpSession session) {}
/// <summary>
/// Handle session connected notification
/// </summary>
/// <param name="session">Connected session</param>
protected virtual void OnConnected(TcpSession session) {}
/// <summary>
/// Handle session disconnecting notification
/// </summary>
/// <param name="session">Disconnecting session</param>
protected virtual void OnDisconnecting(TcpSession session) {}
/// <summary>
/// Handle session disconnected notification
/// </summary>
/// <param name="session">Disconnected session</param>
protected virtual void OnDisconnected(TcpSession session) {}
/// <summary>
/// Handle error notification
/// </summary>
/// <param name="error">Socket error code</param>
protected virtual void OnError(SocketError error) {}
internal void OnConnectingInternal(TcpSession session) { OnConnecting(session); }
internal void OnConnectedInternal(TcpSession session) { OnConnected(session); }
internal void OnDisconnectingInternal(TcpSession session) { OnDisconnecting(session); }
internal void OnDisconnectedInternal(TcpSession session) { OnDisconnected(session); }
#endregion
#region Error handling
/// <summary>
/// Send error notification
/// </summary>
/// <param name="error">Socket error code</param>
private void SendError(SocketError error)
{
// Skip disconnect errors
if ((error == SocketError.ConnectionAborted) ||
(error == SocketError.ConnectionRefused) ||
(error == SocketError.ConnectionReset) ||
(error == SocketError.OperationAborted) ||
(error == SocketError.Shutdown))
return;
OnError(error);
}
#endregion
#region IDisposable implementation
/// <summary>
/// Disposed flag
/// </summary>
public bool IsDisposed { get; private set; }
/// <summary>
/// Acceptor socket disposed flag
/// </summary>
public bool IsSocketDisposed { get; private set; } = true;
// Implement IDisposable.
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposingManagedResources)
{
// The idea here is that Dispose(Boolean) knows whether it is
// being called to do explicit cleanup (the Boolean is true)
// versus being called due to a garbage collection (the Boolean
// is false). This distinction is useful because, when being
// disposed explicitly, the Dispose(Boolean) method can safely
// execute code using reference type fields that refer to other
// objects knowing for sure that these other objects have not been
// finalized or disposed of yet. When the Boolean is false,
// the Dispose(Boolean) method should not execute code that
// refer to reference type fields because those objects may
// have already been finalized."
if (!IsDisposed)
{
if (disposingManagedResources)
{
// Dispose managed resources here...
Stop();
}
// Dispose unmanaged resources here...
// Set large fields to null here...
// Mark as disposed.
IsDisposed = true;
}
}
#endregion
}
}