Make Telnet processing packet agnostic.

MBBSEmu/Session/SessionBase.cs

@@ -4,7 +4,6 @@
 using MBBSEmu.Module;
 using MBBSEmu.Server;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;

MBBSEmu/Session/Telnet/EnumIacOptions.cs

@@ -2,20 +2,64 @@
 {
     /// <summary>
     ///     Enumerator for IAC Options that MBBSEmu will handle
+    ///
+    ///     https://www.iana.org/assignments/telnet-options/telnet-options.xhtml
     /// </summary>
     public enum EnumIacOptions : byte
     {
         BinaryTransmission = 0,
         Echo = 1,
+        Reconnection = 2,
         SuppressGoAhead = 3,
+        ApproximateMessageSizeNegotiation = 4,
         Status = 5,
         TimingMark = 6,
+        RemoteControlledTransAndEcho = 7,
+        OutputLineWidth = 8,
+        OutputPageSize = 9,
+        OutputCarrigeReturnDisposition = 10,
+        OutputHorizontalTabStops = 11,
+        OutputHorizontalTabDisposition = 12,
+        OutputFormfeedDisposition = 13,
+        OutputVerticalTabStops = 14,
+        OutputVerticalTabDisposition = 15,
+        OutputLineFeedDisposition = 16,
+        ExtendedAscii = 17,
+        Logout = 18,
+        ByteMacro = 19,
+        DataEntryTerminal = 20,
+        SUPDUP = 21,
+        SUPDUPOutput = 22,
+        SendLocation = 23,
         TerminalType = 24,
+        EndOfRecord = 25,
+        TACACSUserIdentification = 26,
+        OutputMarking = 27,
+        TerminalLocationNumber = 28,
+        Telnet3270Regime = 29,
+        X_3Pad = 30,
         NegotiateAboutWindowSize = 31,
         TerminalSpeed = 32,
         RemoteFlowControl = 33,
         Linemode = 34,
+        XDisplayLocation = 35,
         EnvironmentOption = 36,
+        AuthenticationOption = 37,
+        EncryptionOption = 38,
+        NewEnvironmentOption = 39,
+        TN3270E = 40,
+        XAUTH = 41,
+        CHARSET = 42,
+        TelnetRemoteSerialPort = 43,
+        ComPortControlOption = 44,
+        TelnetSuppressLocalEcho = 45,
+        TelnetStartTLS = 46,
+        KERMIT = 47,
+        SEND_URL = 48,
+        FORWARD_X = 49,
+        TELOPTPragmaLogon = 138,
+        TELOPT_SSPI_Logon = 139,
+        TELOPTPragmaHeartbeat = 140,
         None = 0xFF
     }
 }

MBBSEmu/Session/Telnet/IacFilter.cs

@@ -0,0 +1,122 @@
+using NLog;
+using System.IO;
+using System;
+
+namespace MBBSEmu.Session.Telnet
+{
+    /// <summary>
+    ///     Parses incoming client Telnet data and invokes the IacVerbReceived
+    ///     event when a verb is received.
+    /// </summary>
+    public class IacFilter
+    {
+        private readonly ILogger _logger;
+
+        private const byte IAC = (byte) 0xFF;
+
+        private const byte SB = (byte) 0xFA;
+        private const byte SE = (byte) 0xF0;
+
+        private enum ParseState {
+            Normal,
+            FoundIAC,
+            IACCommand,
+            SBStart,
+            SBValue,
+            SBIAC
+        }
+
+        // for jumbo frame size
+        private readonly MemoryStream _memoryStream = new MemoryStream(10000);
+        private ParseState _parseState = ParseState.Normal;
+        private EnumIacVerbs _currentVerb;
+
+        public class IacVerbReceivedEventArgs : EventArgs
+        {
+            public EnumIacVerbs Verb { get; set; }
+            public EnumIacOptions Option { get; set; }
+        }
+
+        public event EventHandler<IacVerbReceivedEventArgs> IacVerbReceived;
+
+        public IacFilter(ILogger logger)
+        {
+            _logger = logger;
+        }
+
+        public (byte[], int) ProcessIncomingClientData(byte[] clientData, int bytesReceived)
+        {
+            _memoryStream.SetLength(0);
+
+            for (int i = 0; i < bytesReceived; ++i)
+            {
+                process(clientData[i]);
+            }
+
+            return (_memoryStream.GetBuffer(), (int)_memoryStream.Length);
+        }
+
+        private void process(byte b)
+        {
+        switch (_parseState) {
+            case ParseState.Normal:
+                if (b == IAC)
+                {
+                    _parseState = ParseState.FoundIAC;
+                }
+                else
+                {
+                    _memoryStream.WriteByte(b);
+                }
+                break;
+            case ParseState.FoundIAC:
+                if (b == SB)
+                {
+                    _parseState = ParseState.SBStart;
+                }
+                else if (b == (byte)EnumIacVerbs.WILL || b == (byte)EnumIacVerbs.WONT || b == (byte)EnumIacVerbs.DO || b == (byte)EnumIacVerbs.DONT)
+                {
+                    _currentVerb = (EnumIacVerbs) b;
+                    _parseState = ParseState.IACCommand;
+                }
+                else if (b == IAC)
+                {
+                     // special escape sequence
+                    _memoryStream.WriteByte(b);
+                }
+                else
+                {
+                    _parseState = ParseState.Normal;
+                }
+                break;
+            case ParseState.IACCommand:
+                IacVerbReceived?.Invoke(this, new IacVerbReceivedEventArgs()
+                {
+                    Verb = _currentVerb,
+                    Option = (EnumIacOptions)b
+                });
+                _parseState = ParseState.Normal;
+                break;
+            case ParseState.SBStart:
+                _parseState = ParseState.SBValue;
+                break;
+            case ParseState.SBValue:
+                if (b == IAC)
+                {
+                    _parseState = ParseState.SBIAC;
+                }
+                break;
+            case ParseState.SBIAC:
+                if (b == SE)
+                {
+                    _parseState = ParseState.Normal;
+                }
+                else
+                {
+                    _parseState = ParseState.SBValue;
+                }
+                break;
+            }
+        }
+    }
+}

MBBSEmu/Session/Telnet/IacResponse.cs

@@ -27,5 +27,23 @@ public byte[] ToArray()
             msOutput.WriteByte((byte)Option);
             return msOutput.ToArray();
         }
+
+        public override bool Equals(object obj)
+        {
+            return Equals(obj as IacResponse);
+        }
+
+        public bool Equals(IacResponse other)
+        {
+            if (other == null)
+                return false;
+
+            return (Verb == other.Verb && Option == other.Option);
+        }
+
+        public override int GetHashCode()
+        {
+            return Verb.GetHashCode() ^ Option.GetHashCode();
+        }
     }
 }