451 lines
16 KiB
C#
451 lines
16 KiB
C#
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// Telenor Inpli TFTP Server Module
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//
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// Copyright 2018 Telenor Inpli AS Norway
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// Modified 2020 Antmicro <www.antmicro.com>
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namespace libtftp
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{
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using System;
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using System.Collections.Concurrent;
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using System.IO;
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using System.Linq;
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using System.Net;
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using System.Runtime.InteropServices;
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using System.Threading.Tasks;
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using System.Timers;
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public class TftpServer : IDisposable
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{
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/// <summary>
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/// A singleton instance of the TFTP server object
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/// </summary>
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public static TftpServer Instance
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{
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get
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{
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if (_instance == null)
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_instance = new TftpServer();
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return _instance;
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}
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}
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private static TftpServer _instance;
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/// <summary>
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/// An event handler for when a file is received
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/// </summary>
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public EventHandler<TftpTransferCompleteEventArgs> FileReceived;
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/// <summary>
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/// An async event handler for when a file is received
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/// </summary>
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public event Func<object, TftpTransferCompleteEventArgs, Task> FileReceivedAsync;
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/// <summary>
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/// An event handler for when a file is finished transmitting
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/// </summary>
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public EventHandler<TftpTransferCompleteEventArgs> FileTransmitted;
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/// <summary>
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/// An async event handler for when a file is finished transmitting
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/// </summary>
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public event Func<object, TftpTransferCompleteEventArgs, Task> FileTransmittedAsync;
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/// <summary>
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/// An event handler for when an error occurs during file receive
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/// </summary>
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public EventHandler<TftpTransferErrorEventArgs> FileReceiveError;
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/// <summary>
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/// An async event handler for when a file is received
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/// </summary>
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public event Func<object, TftpTransferErrorEventArgs, Task> FileReceiveErrorAsync;
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/// <summary>
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/// An event handler for when an error occurs during file transmit
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/// </summary>
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public EventHandler<TftpTransferErrorEventArgs> FileTransmitError;
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/// <summary>
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/// An async event handler for when an error occurs during file transmit
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/// </summary>
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public event Func<object, TftpTransferErrorEventArgs, Task> FileTransmitErrorAsync;
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/// <summary>
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/// An event called to log a message
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/// </summary>
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public EventHandler<TftpLogEventArgs> Log;
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/// <summary>
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/// When a read request comes in, this event is a callback to provide the stream to be transferred
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/// </summary>
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public event Func<object, TftpGetStreamEventArgs, Task> GetStream;
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/// <summary>
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/// The maximum period of idle time to retain a session in memory before cleaning it up
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/// </summary>
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public TimeSpan MaximumIdleSession { get; } = TimeSpan.FromSeconds(5);
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/// <summary>
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/// The maximum time to wait before retransmitting an unacknowledged packet
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/// </summary>
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public TimeSpan RetransmissionTimeout { get; } = TimeSpan.FromMilliseconds(1000);
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/// <summary>
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/// The log level for the server to reach before logging.
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/// </summary>
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public ETftpLogSeverity LogSeverity { get; set; } = ETftpLogSeverity.Informational;
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/// <summary>
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/// Response packet is ready.
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/// </summary>
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public Action<IPEndPoint, byte[], int> DataReady { get; set; }
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private Timer PeriodicTimer;
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private ConcurrentDictionary<IPEndPoint, TftpSession> Sessions { get; set; } = new ConcurrentDictionary<IPEndPoint, TftpSession>();
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/// <summary>
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/// Constructor
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/// </summary>
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public TftpServer()
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{
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}
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public void Reset()
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{
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Sessions.Clear();
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}
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/// <summary>
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/// Start the server (periodic timer)
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/// </summary>
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public void Start()
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{
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PeriodicTimer = new Timer(500);
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PeriodicTimer.Elapsed += PeriodicTimer_Elapsed;
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PeriodicTimer.Start();
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}
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/// <summary>
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/// Handle the incoming UDP packet
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/// </summary>
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public void OnUdpData(IPEndPoint source, byte[] messageData)
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{
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try
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{
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if (!Sessions.TryGetValue(source, out TftpSession session))
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{
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LogDebug($"New client detected from {source.Address}:{source.Port}");
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session = new TftpSession(this, source);
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Sessions[source] = session;
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}
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Task.Factory.StartNew(
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async () => {
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try
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{
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await session.OnReceiveAsync(messageData);
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}
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catch (Exception e)
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{
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LogError("Internal error: " + e.Message);
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}
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}
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);
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}
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catch (Exception e)
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{
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LogError("Internal error: " + e.Message);
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}
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}
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private void EmitSessionError(TftpSession session, string reason)
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{
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EventHandler<TftpTransferErrorEventArgs> handler =
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(session.Operation == ETftpOperationType.WriteOperation) ?
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FileReceiveError :
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FileTransmitError
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;
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var eventArgs = new TftpTransferErrorEventArgs
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{
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Id = session.Id,
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Operation = session.Operation,
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Filename = session.Filename,
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RemoteHost = session.RemoteHost,
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Stream = (session.Operation == ETftpOperationType.WriteOperation) ? (MemoryStream)session.TransferStream : null,
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TransferInitiated = session.TransferRequestInitiated,
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TransferCompleted = DateTimeOffset.Now,
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Transferred = session.Position,
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FailureReason = reason
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};
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handler?.Invoke(
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this,
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eventArgs
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);
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var invocationList =
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(session.Operation == ETftpOperationType.WriteOperation) ?
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(FileReceiveErrorAsync?.GetInvocationList()) :
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(FileTransmitErrorAsync?.GetInvocationList())
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;
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if (invocationList == null)
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return;
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var handlerTasks = new Task[invocationList.Length];
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for (int i = 0; i < invocationList.Length; i++)
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handlerTasks[i] = ((Func<object, TftpTransferErrorEventArgs, Task>)invocationList[i])(this, eventArgs);
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Task.WhenAll(handlerTasks);
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}
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private void ClearIdleSessions()
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{
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var now = DateTimeOffset.Now;
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var idledOutSessions = Sessions.Where(x => now.Subtract(x.Value.IdleSince) > MaximumIdleSession);
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foreach (var session in idledOutSessions)
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{
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UnregisterSession(session.Value, "timeout");
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}
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}
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private void PeriodicTimer_Elapsed(object sender, ElapsedEventArgs e)
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{
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var now = DateTimeOffset.Now;
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ClearIdleSessions();
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var retransmitSessions = Sessions
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.Where(x =>
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x.Value.Operation == ETftpOperationType.ReadOperation &&
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now.Subtract(x.Value.IdleSince) > RetransmissionTimeout
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);
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var handlerTasks = retransmitSessions.Select(x => Task.Factory.StartNew(() => x.Value.RetransmitAsync()));
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Task.WhenAll(handlerTasks);
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}
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/// <summary>
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/// Called by sessions to request a transfer stream from the host application
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/// </summary>
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/// <param name="sessionId">Session Id</param>
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/// <param name="remoteHost">The remote host requesting the transfer</param>
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/// <param name="filename">The filename requested by the remote host</param>
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/// <returns></returns>
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internal async Task<Stream> GetReadStreamAsync(Guid sessionId, IPEndPoint remoteHost, string filename)
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{
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if(GetStream == null)
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{
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LogError("No file system available");
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return null;
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}
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var eventArgs = new TftpGetStreamEventArgs
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{
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Id = sessionId,
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Filename = filename,
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RemoteHost = remoteHost
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};
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Delegate[] invocationList = GetStream.GetInvocationList();
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Task[] handlerTasks = new Task[invocationList.Length];
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for (int i = 0; i < invocationList.Length; i++)
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{
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handlerTasks[i] = ((Func<object, TftpGetStreamEventArgs, Task>)invocationList[i])(this, eventArgs);
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}
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await Task.WhenAll(handlerTasks);
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if(eventArgs.Result == null)
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{
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LogError("Unknown file");
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return null;
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}
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return eventArgs.Result;
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}
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/// <summary>
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/// Called by a session to remove itself when it's no longer needed
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/// </summary>
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/// <param name="tftpSession">The session to remove</param>
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internal void UnregisterSession(TftpSession tftpSession)
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{
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if (!Sessions.TryRemove(tftpSession.RemoteHost, out TftpSession removedSession))
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throw new Exception("Could not remove session " + tftpSession.RemoteHost.ToString() + " from known sessions");
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}
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/// <summary>
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/// Called by a session to remove itself when it's no longer needed
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/// </summary>
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/// <param name="tftpSession">The session to remove</param>
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internal void UnregisterSession(TftpSession tftpSession, string errorReason)
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{
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if (!Sessions.TryRemove(tftpSession.RemoteHost, out TftpSession removedSession))
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throw new Exception("Could not remove session " + tftpSession.RemoteHost.ToString() + " from known sessions");
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EmitSessionError(tftpSession, errorReason);
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}
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/// <summary>
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/// Called by a session to signal that it's complete
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/// </summary>
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/// <param name="session">The transfer which is complete</param>
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internal async Task TransferCompleteAsync(TftpSession session)
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{
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UnregisterSession(session);
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EventHandler<TftpTransferCompleteEventArgs> handler =
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(session.Operation == ETftpOperationType.WriteOperation) ?
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FileReceived :
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FileTransmitted
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;
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var eventArgs = new TftpTransferCompleteEventArgs
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{
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Id = session.Id,
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Operation = session.Operation,
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Filename = session.Filename,
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RemoteHost = session.RemoteHost,
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Stream = (session.Operation == ETftpOperationType.WriteOperation) ? (MemoryStream)session.TransferStream : null,
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TransferInitiated = session.TransferRequestInitiated,
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TransferCompleted = DateTimeOffset.Now,
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Transferred = session.Position
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};
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handler?.Invoke(
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this,
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eventArgs
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);
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var invocationList =
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(session.Operation == ETftpOperationType.WriteOperation) ?
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(FileReceivedAsync?.GetInvocationList()) :
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(FileTransmittedAsync?.GetInvocationList())
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;
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if (invocationList == null)
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return;
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var handlerTasks = new Task[invocationList.Length];
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for (int i = 0; i < invocationList.Length; i++)
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{
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handlerTasks[i] =
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((Func<object, TftpTransferCompleteEventArgs, Task>)invocationList[i])(
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this,
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new TftpTransferCompleteEventArgs
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{
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Id = session.Id,
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Operation = session.Operation,
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Filename = session.Filename,
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RemoteHost = session.RemoteHost,
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Stream = (session.Operation == ETftpOperationType.WriteOperation) ? (MemoryStream)session.TransferStream : null,
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TransferInitiated = session.TransferRequestInitiated,
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TransferCompleted = DateTimeOffset.Now,
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Transferred = session.Position
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}
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);
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}
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await Task.WhenAll(handlerTasks);
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}
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/// <summary>
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/// Used to send a packet to a host
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/// </summary>
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/// <param name="destination">The endpoint to transfer to</param>
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/// <param name="buffer">The data to transmit</param>
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internal void Transmit(IPEndPoint destination, byte[] buffer)
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{
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Transmit(destination, buffer, buffer.Length);
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}
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/// <summary>
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/// Transmit a packet to a remote host
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/// </summary>
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/// <param name="destination">The host to transmit to</param>
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/// <param name="buffer">The buffer to transmit</param>
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/// <param name="length">The length of the data to transfer</param>
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internal void Transmit(IPEndPoint destination, byte[] buffer, int length)
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{
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DataReady?.Invoke(destination, buffer, length);
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}
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/// <summary>
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/// Implementation of the IDisposable interface
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/// </summary>
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public void Dispose()
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{
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|||
|
|
PeriodicTimer.Stop();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Syslog an error level message
|
|||
|
|
/// </summary>
|
|||
|
|
/// <param name="message">The message to log</param>
|
|||
|
|
internal void LogError(string message)
|
|||
|
|
{
|
|||
|
|
if (Log != null && LogSeverity >= ETftpLogSeverity.Error)
|
|||
|
|
{
|
|||
|
|
Log.Invoke(
|
|||
|
|
this,
|
|||
|
|
new TftpLogEventArgs
|
|||
|
|
{
|
|||
|
|
Severity = ETftpLogSeverity.Error,
|
|||
|
|
TimeStamp = DateTimeOffset.Now,
|
|||
|
|
Message = message
|
|||
|
|
}
|
|||
|
|
);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Syslog an infortmational level message
|
|||
|
|
/// </summary>
|
|||
|
|
/// <param name="message">The message to log</param>
|
|||
|
|
internal void LogInfo(string message)
|
|||
|
|
{
|
|||
|
|
if (Log != null && LogSeverity >= ETftpLogSeverity.Informational)
|
|||
|
|
{
|
|||
|
|
Log.Invoke(
|
|||
|
|
this,
|
|||
|
|
new TftpLogEventArgs
|
|||
|
|
{
|
|||
|
|
Severity = ETftpLogSeverity.Informational,
|
|||
|
|
TimeStamp = DateTimeOffset.Now,
|
|||
|
|
Message = message
|
|||
|
|
}
|
|||
|
|
);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Syslog a debug level message
|
|||
|
|
/// </summary>
|
|||
|
|
/// <param name="message">The message to log</param>
|
|||
|
|
internal void LogDebug(string message)
|
|||
|
|
{
|
|||
|
|
if (Log != null && LogSeverity >= ETftpLogSeverity.Debug)
|
|||
|
|
{
|
|||
|
|
Log.Invoke(
|
|||
|
|
this,
|
|||
|
|
new TftpLogEventArgs
|
|||
|
|
{
|
|||
|
|
Severity = ETftpLogSeverity.Debug,
|
|||
|
|
TimeStamp = DateTimeOffset.Now,
|
|||
|
|
Message = message
|
|||
|
|
}
|
|||
|
|
);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|