| 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 | } |