#nullable disable using Fleck; using System; using System.Collections.Generic; using System.IO; using System.Net; using System.Net.Sockets; using System.Runtime.InteropServices; using System.Security.Authentication; using System.Security.Cryptography.X509Certificates; using System.Text; // Near direct reimplementation of Fleck's WebSocketServer with address reusing // Fleck's Socket wrapper doesn't provide any way to do this with the normally provided APIs // https://github.com/statianzo/Fleck/blob/1.1.0/src/Fleck/WebSocketServer.cs namespace SharpChat { public class SharpChatWebSocketServer : IWebSocketServer { private readonly string _scheme; private readonly IPAddress _locationIP; private Action _config; public SharpChatWebSocketServer(string location, bool supportDualStack = true) { Uri uri = new(location); Port = uri.Port; Location = location; SupportDualStack = supportDualStack; _locationIP = ParseIPAddress(uri); _scheme = uri.Scheme; Socket socket = new(_locationIP.AddressFamily, SocketType.Stream, ProtocolType.IP); socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, 1); if(SupportDualStack && Type.GetType("Mono.Runtime") == null && RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) { socket.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, false); } ListenerSocket = new SocketWrapper(socket); SupportedSubProtocols = Array.Empty(); } public ISocket ListenerSocket { get; set; } public string Location { get; private set; } public bool SupportDualStack { get; } public int Port { get; private set; } public X509Certificate2 Certificate { get; set; } public SslProtocols EnabledSslProtocols { get; set; } public IEnumerable SupportedSubProtocols { get; set; } public bool RestartAfterListenError { get; set; } public bool IsSecure { get { return _scheme == "wss" && Certificate != null; } } public void Dispose() { ListenerSocket.Dispose(); GC.SuppressFinalize(this); } private static IPAddress ParseIPAddress(Uri uri) { string ipStr = uri.Host; if(ipStr == "0.0.0.0") { return IPAddress.Any; } else if(ipStr == "[0000:0000:0000:0000:0000:0000:0000:0000]") { return IPAddress.IPv6Any; } else { try { return IPAddress.Parse(ipStr); } catch(Exception ex) { throw new FormatException("Failed to parse the IP address part of the location. Please make sure you specify a valid IP address. Use 0.0.0.0 or [::] to listen on all interfaces.", ex); } } } public void Start(Action config) { IPEndPoint ipLocal = new(_locationIP, Port); ListenerSocket.Bind(ipLocal); ListenerSocket.Listen(100); Port = ((IPEndPoint)ListenerSocket.LocalEndPoint).Port; FleckLog.Info(string.Format("Server started at {0} (actual port {1})", Location, Port)); if(_scheme == "wss") { if(Certificate == null) { FleckLog.Error("Scheme cannot be 'wss' without a Certificate"); return; } if(EnabledSslProtocols == SslProtocols.None) { EnabledSslProtocols = SslProtocols.Tls; FleckLog.Debug("Using default TLS 1.0 security protocol."); } } ListenForClients(); _config = config; } private void ListenForClients() { ListenerSocket.Accept(OnClientConnect, e => { FleckLog.Error("Listener socket is closed", e); if(RestartAfterListenError) { FleckLog.Info("Listener socket restarting"); try { ListenerSocket.Dispose(); Socket socket = new(_locationIP.AddressFamily, SocketType.Stream, ProtocolType.IP); socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, 1); ListenerSocket = new SocketWrapper(socket); Start(_config); FleckLog.Info("Listener socket restarted"); } catch(Exception ex) { FleckLog.Error("Listener could not be restarted", ex); } } }); } private void OnClientConnect(ISocket clientSocket) { if(clientSocket == null) return; // socket closed FleckLog.Debug(string.Format("Client connected from {0}:{1}", clientSocket.RemoteIpAddress, clientSocket.RemotePort.ToString())); ListenForClients(); WebSocketConnection connection = null; connection = new WebSocketConnection( clientSocket, _config, bytes => RequestParser.Parse(bytes, _scheme), r => { try { return HandlerFactory.BuildHandler( r, s => connection.OnMessage(s), connection.Close, b => connection.OnBinary(b), b => connection.OnPing(b), b => connection.OnPong(b) ); } catch(WebSocketException) { const string responseMsg = "HTTP/1.1 200 OK\r\n" + "Date: {0}\r\n" + "Server: SharpChat\r\n" + "Content-Length: {1}\r\n" + "Content-Type: text/html; charset=utf-8\r\n" + "Connection: close\r\n" + "\r\n" + "{2}"; string responseBody = File.Exists("http-motd.txt") ? File.ReadAllText("http-motd.txt") : "SharpChat"; clientSocket.Stream.Write(Encoding.UTF8.GetBytes(string.Format( responseMsg, DateTimeOffset.Now.ToString("r"), Encoding.UTF8.GetByteCount(responseBody), responseBody ))); clientSocket.Close(); return null; } }, s => SubProtocolNegotiator.Negotiate(SupportedSubProtocols, s)); if(IsSecure) { FleckLog.Debug("Authenticating Secure Connection"); clientSocket .Authenticate(Certificate, EnabledSslProtocols, connection.StartReceiving, e => FleckLog.Warn("Failed to Authenticate", e)); } else { connection.StartReceiving(); } } } }