src/jexer/net/TelnetSocket.java

   1 /**
   2  * Jexer - Java Text User Interface
   3  *
   4  * License: LGPLv3 or later
   5  *
   6  * This module is licensed under the GNU Lesser General Public License
   7  * Version 3.  Please see the file "COPYING" in this directory for more
   8  * information about the GNU Lesser General Public License Version 3.
   9  *
  10  *     Copyright (C) 2015  Kevin Lamonte
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public License
  14  * as published by the Free Software Foundation; either version 3 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this program; if not, see
  24  * http://www.gnu.org/licenses/, or write to the Free Software
  25  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  26  * 02110-1301 USA
  27  *
  28  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  29  * @version 1
  30  */
  31 package jexer.net;
  32
  33 import java.io.InputStream;
  34 import java.io.IOException;
  35 import java.io.OutputStream;
  36 import java.net.Socket;
  37
  38 /**
  39  * This class provides a Socket that performs the telnet protocol to both
  40  * establish an 8-bit clean no echo channel and expose window resize events
  41  * to the Jexer ECMA48 backend.
  42  */
  43 public final class TelnetSocket extends Socket {
  44
  45     /**
  46      * The telnet-aware socket InputStream.
  47      */
  48     private TelnetInputStream input;
  49
  50     /**
  51      * The telnet-aware socket OutputStream.
  52      */
  53     private TelnetOutputStream output;
  54
  55     // Telnet protocol special characters.  Note package private access.
  56     static final int TELNET_SE         = 240;
  57     static final int TELNET_NOP        = 241;
  58     static final int TELNET_DM         = 242;
  59     static final int TELNET_BRK        = 243;
  60     static final int TELNET_IP         = 244;
  61     static final int TELNET_AO         = 245;
  62     static final int TELNET_AYT        = 246;
  63     static final int TELNET_EC         = 247;
  64     static final int TELNET_EL         = 248;
  65     static final int TELNET_GA         = 249;
  66     static final int TELNET_SB         = 250;
  67     static final int TELNET_WILL       = 251;
  68     static final int TELNET_WONT       = 252;
  69     static final int TELNET_DO         = 253;
  70     static final int TELNET_DONT       = 254;
  71     static final int TELNET_IAC        = 255;
  72     static final int C_NUL             = 0x00;
  73     static final int C_LF              = 0x0A;
  74     static final int C_CR              = 0x0D;
  75
  76     /**
  77      * If true, this is a server socket (i.e. created by accept()).
  78      */
  79     boolean isServer = true;
  80
  81     /**
  82      * If true, telnet ECHO mode is set such that local echo is off and
  83      * remote echo is on.  This is appropriate for server sockets.
  84      */
  85     boolean echoMode = false;
  86
  87     /**
  88      * If true, telnet BINARY mode is enabled.  We always want this to
  89      * ensure a Unicode-safe stream.
  90      */
  91     boolean binaryMode = false;
  92
  93     /**
  94      * If true, the SUPPRESS-GO-AHEAD option is enabled.  We always want
  95      * this.
  96      */
  97     boolean goAhead = true;
  98
  99     /**
 100      * If true, request the client terminal type.
 101      */
 102     boolean doTermType = true;
 103
 104     /**
 105      * If true, request the client terminal speed.
 106      */
 107     boolean doTermSpeed = true;
 108
 109     /**
 110      * If true, request the Negotiate About Window Size option to
 111      * determine the client text width/height.
 112      */
 113     boolean doNAWS = true;
 114
 115     /**
 116      * If true, request the New Environment option to obtain the client
 117      * LOGNAME, USER, and LANG variables.
 118      */
 119     boolean doEnvironment;
 120
 121     /**
 122      * The terminal type reported by the client.
 123      */
 124     String terminalType = "";
 125
 126     /**
 127      * The terminal speed reported by the client.
 128      */
 129     String terminalSpeed = "";
 130
 131     /**
 132      * See if telnet server/client is in ASCII mode.
 133      *
 134      * @return if true, this connection is in ASCII mode
 135      */
 136     public boolean isAscii() {
 137         return (!binaryMode);
 138     }
 139
 140     /**
 141      * Creates a Socket that knows the telnet protocol.  Note package private
 142      * access, this is only used by TelnetServerSocket.
 143      *
 144      * @throws IOException if an I/O error occurs
 145      */
 146     TelnetSocket() throws IOException {
 147         super();
 148     }
 149
 150     // Socket interface -------------------------------------------------------
 151
 152     /**
 153      * Returns an input stream for this socket.
 154      *
 155      * @return the input stream
 156      * @throws IOException if an I/O error occurs
 157      */
 158     @Override
 159     public InputStream getInputStream() throws IOException {
 160         if (input == null) {
 161             assert (output == null);
 162             output = new TelnetOutputStream(this, super.getOutputStream());
 163             input = new TelnetInputStream(this, super.getInputStream(), output);
 164             input.telnetSendOptions();
 165         }
 166         return input;
 167     }
 168
 169     /**
 170      * Returns an output stream for this socket.
 171      *
 172      * @return the output stream
 173      * @throws IOException if an I/O error occurs
 174      */
 175     @Override
 176     public OutputStream getOutputStream() throws IOException {
 177         if (output == null) {
 178             assert (input == null);
 179             output = new TelnetOutputStream(this, super.getOutputStream());
 180             input = new TelnetInputStream(this, super.getInputStream(), output);
 181             input.telnetSendOptions();
 182         }
 183         return output;
 184     }
 185
 186 }