| 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 wrapped socket. |
| 47 | */ |
| 48 | private Socket socket; |
| 49 | |
| 50 | /** |
| 51 | * The telnet-aware socket InputStream. |
| 52 | */ |
| 53 | private TelnetInputStream input; |
| 54 | |
| 55 | /** |
| 56 | * The telnet-aware socket OutputStream. Note package private access: |
| 57 | * input sends stuff to output. |
| 58 | */ |
| 59 | TelnetOutputStream output; |
| 60 | |
| 61 | // Telnet protocol special characters. Note package private access. |
| 62 | public static final int TELNET_SE = 240; |
| 63 | public static final int TELNET_NOP = 241; |
| 64 | public static final int TELNET_DM = 242; |
| 65 | public static final int TELNET_BRK = 243; |
| 66 | public static final int TELNET_IP = 244; |
| 67 | public static final int TELNET_AO = 245; |
| 68 | public static final int TELNET_AYT = 246; |
| 69 | public static final int TELNET_EC = 247; |
| 70 | public static final int TELNET_EL = 248; |
| 71 | public static final int TELNET_GA = 249; |
| 72 | public static final int TELNET_SB = 250; |
| 73 | public static final int TELNET_WILL = 251; |
| 74 | public static final int TELNET_WONT = 252; |
| 75 | public static final int TELNET_DO = 253; |
| 76 | public static final int TELNET_DONT = 254; |
| 77 | public static final int TELNET_IAC = 255; |
| 78 | public static final int C_NUL = 0x00; |
| 79 | public static final int C_LF = 0x0A; |
| 80 | public static final int C_CR = 0x0D; |
| 81 | |
| 82 | /** |
| 83 | * Telnet protocol speaks to a Network Virtual Terminal (NVT). |
| 84 | */ |
| 85 | class TelnetState { |
| 86 | |
| 87 | // General status flags outside the NVT spec |
| 88 | boolean doInit; |
| 89 | boolean isServer; |
| 90 | |
| 91 | // NVT flags |
| 92 | boolean echoMode; |
| 93 | boolean binaryMode; |
| 94 | boolean goAhead; |
| 95 | boolean doTermType; |
| 96 | boolean doTermSpeed; |
| 97 | boolean doNAWS; |
| 98 | boolean doEnvironment; |
| 99 | String terminal = ""; |
| 100 | |
| 101 | // Flags used by the TelnetInputStream |
| 102 | boolean iac; |
| 103 | boolean dowill; |
| 104 | int dowillType; |
| 105 | boolean subnegEnd; |
| 106 | boolean isEof; |
| 107 | boolean eofMsg; |
| 108 | boolean readCR; |
| 109 | |
| 110 | // Flags used by the TelnetOutputStream |
| 111 | boolean writeCR; |
| 112 | |
| 113 | /** |
| 114 | * Constuctor calls reset(). |
| 115 | */ |
| 116 | public TelnetState() { |
| 117 | reset(); |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Reset NVT to default state as per RFC 854. |
| 122 | */ |
| 123 | public void reset() { |
| 124 | echoMode = false; |
| 125 | binaryMode = false; |
| 126 | goAhead = true; |
| 127 | doTermType = true; |
| 128 | doTermSpeed = true; |
| 129 | doNAWS = true; |
| 130 | doEnvironment = true; |
| 131 | doInit = true; |
| 132 | isServer = true; |
| 133 | |
| 134 | iac = false; |
| 135 | dowill = false; |
| 136 | subnegEnd = false; |
| 137 | isEof = false; |
| 138 | eofMsg = false; |
| 139 | readCR = false; |
| 140 | |
| 141 | writeCR = false; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * State of the protocol. Note package private access. |
| 147 | */ |
| 148 | TelnetState nvt; |
| 149 | |
| 150 | /** |
| 151 | * See if telnet server/client is in ASCII mode. |
| 152 | * |
| 153 | * @return if true, this connection is in ASCII mode |
| 154 | */ |
| 155 | public boolean isAscii() { |
| 156 | return (!nvt.binaryMode); |
| 157 | } |
| 158 | |
| 159 | /** |
| 160 | * Creates a Socket that knows the telnet protocol. |
| 161 | * |
| 162 | * @param socket the underlying Socket |
| 163 | */ |
| 164 | TelnetSocket(Socket socket) throws IOException { |
| 165 | super(); |
| 166 | nvt = new TelnetState(); |
| 167 | this.socket = socket; |
| 168 | |
| 169 | output = new TelnetOutputStream(this, super.getOutputStream()); |
| 170 | input = new TelnetInputStream(this, super.getInputStream(), output); |
| 171 | |
| 172 | // Initiate the telnet protocol negotiation. |
| 173 | input.telnetSendOptions(); |
| 174 | } |
| 175 | |
| 176 | // Socket interface ------------------------------------------------------- |
| 177 | |
| 178 | /** |
| 179 | * Returns an input stream for this socket. |
| 180 | * |
| 181 | * @return the input stream |
| 182 | */ |
| 183 | @Override |
| 184 | public InputStream getInputStream() throws IOException { |
| 185 | return input; |
| 186 | } |
| 187 | |
| 188 | /** |
| 189 | * Returns an output stream for this socket. |
| 190 | * |
| 191 | * @return the output stream |
| 192 | */ |
| 193 | @Override |
| 194 | public OutputStream getOutputStream() throws IOException { |
| 195 | return output; |
| 196 | } |
| 197 | |
| 198 | } |