| 1 | /* |
| 2 | * This file is part of lanterna (http://code.google.com/p/lanterna/). |
| 3 | * |
| 4 | * lanterna is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU Lesser General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public License |
| 15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | * |
| 17 | * Copyright (C) 2010-2015 Martin |
| 18 | */ |
| 19 | package com.googlecode.lanterna.terminal.ansi; |
| 20 | |
| 21 | import static com.googlecode.lanterna.terminal.ansi.TelnetProtocol.*; |
| 22 | import java.io.ByteArrayOutputStream; |
| 23 | import java.io.IOException; |
| 24 | import java.io.InputStream; |
| 25 | import java.io.OutputStream; |
| 26 | import java.net.Socket; |
| 27 | import java.net.SocketAddress; |
| 28 | import java.nio.charset.Charset; |
| 29 | import java.util.Arrays; |
| 30 | import java.util.ArrayList; |
| 31 | import java.util.List; |
| 32 | |
| 33 | /** |
| 34 | * This class is used by the {@code TelnetTerminalServer} class when a client has connected in; this class will be the |
| 35 | * interaction point for that client. All operations are sent to the client over the network socket and some of the |
| 36 | * meta-operations (like echo mode) are communicated using Telnet negotiation language. You can't create objects of this |
| 37 | * class directly; they are created for you when you are listening for incoming connections using a |
| 38 | * {@code TelnetTerminalServer} and a client connects. |
| 39 | * <p> |
| 40 | * A good resource on telnet communication is http://www.tcpipguide.com/free/t_TelnetProtocol.htm<br> |
| 41 | * Also here: http://support.microsoft.com/kb/231866 |
| 42 | * @see TelnetTerminalServer |
| 43 | * @author martin |
| 44 | */ |
| 45 | public class TelnetTerminal extends ANSITerminal { |
| 46 | |
| 47 | private final Socket socket; |
| 48 | private final NegotiationState negotiationState; |
| 49 | |
| 50 | TelnetTerminal(Socket socket, Charset terminalCharset) throws IOException { |
| 51 | this(socket, new TelnetClientIACFilterer(socket.getInputStream()), socket.getOutputStream(), terminalCharset); |
| 52 | } |
| 53 | |
| 54 | //This weird construction is just so that we can access the input filter without changing the visibility in StreamBasedTerminal |
| 55 | private TelnetTerminal(Socket socket, TelnetClientIACFilterer inputStream, OutputStream outputStream, Charset terminalCharset) throws IOException { |
| 56 | super(inputStream, outputStream, terminalCharset); |
| 57 | this.socket = socket; |
| 58 | this.negotiationState = inputStream.negotiationState; |
| 59 | inputStream.setEventListener(new TelnetClientEventListener() { |
| 60 | @Override |
| 61 | public void onResize(int columns, int rows) { |
| 62 | TelnetTerminal.this.onResized(columns, rows); |
| 63 | } |
| 64 | |
| 65 | @Override |
| 66 | public void requestReply(boolean will, byte option) throws IOException { |
| 67 | writeToTerminal(COMMAND_IAC, will ? COMMAND_WILL : COMMAND_WONT, option); |
| 68 | } |
| 69 | }); |
| 70 | setLineMode0(); |
| 71 | setEchoOff(); |
| 72 | setResizeNotificationOn(); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Returns the socket address for the remote endpoint of the telnet connection |
| 77 | * @return SocketAddress representing the remote client |
| 78 | */ |
| 79 | public SocketAddress getRemoteSocketAddress() { |
| 80 | return socket.getRemoteSocketAddress(); |
| 81 | } |
| 82 | |
| 83 | private void setEchoOff() throws IOException { |
| 84 | writeToTerminal(COMMAND_IAC, COMMAND_WILL, OPTION_ECHO); |
| 85 | flush(); |
| 86 | } |
| 87 | |
| 88 | private void setLineMode0() throws IOException { |
| 89 | writeToTerminal( |
| 90 | COMMAND_IAC, COMMAND_DO, OPTION_LINEMODE, |
| 91 | COMMAND_IAC, COMMAND_SUBNEGOTIATION, OPTION_LINEMODE, (byte)1, (byte)0, COMMAND_IAC, COMMAND_SUBNEGOTIATION_END); |
| 92 | flush(); |
| 93 | } |
| 94 | |
| 95 | private void setResizeNotificationOn() throws IOException { |
| 96 | writeToTerminal( |
| 97 | COMMAND_IAC, COMMAND_DO, OPTION_NAWS); |
| 98 | flush(); |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Retrieves the current negotiation state with the client, containing details on what options have been enabled |
| 103 | * and what the client has said it supports. |
| 104 | * @return The current negotiation state for this client |
| 105 | */ |
| 106 | public NegotiationState getNegotiationState() { |
| 107 | return negotiationState; |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Closes the socket to the client, effectively ending the telnet session and the terminal. |
| 112 | * @throws IOException If there was an underlying I/O error |
| 113 | */ |
| 114 | public void close() throws IOException { |
| 115 | socket.close(); |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * This class contains some of the various states that the Telnet negotiation protocol defines. Lanterna doesn't |
| 120 | * support all of them but the more common ones are represented. |
| 121 | */ |
| 122 | public static class NegotiationState { |
| 123 | private boolean clientEcho; |
| 124 | private boolean clientLineMode0; |
| 125 | private boolean clientResizeNotification; |
| 126 | private boolean suppressGoAhead; |
| 127 | private boolean extendedAscii; |
| 128 | |
| 129 | NegotiationState() { |
| 130 | this.clientEcho = true; |
| 131 | this.clientLineMode0 = false; |
| 132 | this.clientResizeNotification = false; |
| 133 | this.suppressGoAhead = true; |
| 134 | this.extendedAscii = true; |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * Is the telnet client echo mode turned on (client is echoing characters locally) |
| 139 | * @return {@code true} if client echo is enabled |
| 140 | */ |
| 141 | public boolean isClientEcho() { |
| 142 | return clientEcho; |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Is the telnet client line mode 0 turned on (client sends character by character instead of line by line) |
| 147 | * @return {@code true} if client line mode 0 is enabled |
| 148 | */ |
| 149 | public boolean isClientLineMode0() { |
| 150 | return clientLineMode0; |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * Is the telnet client resize notification turned on (client notifies server when the terminal window has |
| 155 | * changed size) |
| 156 | * @return {@code true} if client resize notification is enabled |
| 157 | */ |
| 158 | public boolean isClientResizeNotification() { |
| 159 | return clientResizeNotification; |
| 160 | } |
| 161 | |
| 162 | |
| 163 | /** |
| 164 | * Is the telnet client suppress go-ahead turned on |
| 165 | * @return {@code true} if client suppress go-ahead is enabled |
| 166 | */ |
| 167 | public boolean isSuppressGoAhead() { |
| 168 | return suppressGoAhead; |
| 169 | } |
| 170 | |
| 171 | /** |
| 172 | * Is the telnet client extended ascii turned on |
| 173 | * @return {@code true} if client extended ascii is enabled |
| 174 | */ |
| 175 | public boolean isExtendedAscii() { |
| 176 | return extendedAscii; |
| 177 | } |
| 178 | |
| 179 | private void onUnsupportedStateCommand(boolean enabling, byte value) { |
| 180 | System.err.println("Unsupported operation: Client says it " + (enabling ? "will" : "won't") + " do " + TelnetProtocol.CODE_TO_NAME.get(value)); |
| 181 | } |
| 182 | |
| 183 | private void onUnsupportedRequestCommand(boolean askedToDo, byte value) { |
| 184 | System.err.println("Unsupported request: Client asks us, " + (askedToDo ? "do" : "don't") + " " + TelnetProtocol.CODE_TO_NAME.get(value)); |
| 185 | } |
| 186 | |
| 187 | private void onUnsupportedSubnegotiation(byte option, byte[] additionalData) { |
| 188 | System.err.println("Unsupported subnegotiation: Client send " + TelnetProtocol.CODE_TO_NAME.get(option) + " with extra data " + |
| 189 | toList(additionalData)); |
| 190 | } |
| 191 | |
| 192 | private static List<String> toList(byte[] array) { |
| 193 | List<String> list = new ArrayList<String>(array.length); |
| 194 | for(byte b: array) { |
| 195 | list.add(String.format("%02X ", b)); |
| 196 | } |
| 197 | return list; |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | private interface TelnetClientEventListener { |
| 202 | void onResize(int columns, int rows); |
| 203 | void requestReply(boolean will, byte option) throws IOException; |
| 204 | } |
| 205 | |
| 206 | private static class TelnetClientIACFilterer extends InputStream { |
| 207 | private final NegotiationState negotiationState; |
| 208 | private final InputStream inputStream; |
| 209 | private final byte[] buffer; |
| 210 | private final byte[] workingBuffer; |
| 211 | private int bytesInBuffer; |
| 212 | private TelnetClientEventListener eventListener; |
| 213 | |
| 214 | TelnetClientIACFilterer(InputStream inputStream) { |
| 215 | this.negotiationState = new NegotiationState(); |
| 216 | this.inputStream = inputStream; |
| 217 | this.buffer = new byte[64 * 1024]; |
| 218 | this.workingBuffer = new byte[1024]; |
| 219 | this.bytesInBuffer = 0; |
| 220 | this.eventListener = null; |
| 221 | } |
| 222 | |
| 223 | private void setEventListener(TelnetClientEventListener eventListener) { |
| 224 | this.eventListener = eventListener; |
| 225 | } |
| 226 | |
| 227 | @Override |
| 228 | public int read() throws IOException { |
| 229 | throw new UnsupportedOperationException("TelnetClientIACFilterer doesn't support .read()"); |
| 230 | } |
| 231 | |
| 232 | @Override |
| 233 | public void close() throws IOException { |
| 234 | inputStream.close(); |
| 235 | } |
| 236 | |
| 237 | @Override |
| 238 | public int available() throws IOException { |
| 239 | int underlyingStreamAvailable = inputStream.available(); |
| 240 | if(underlyingStreamAvailable == 0 && bytesInBuffer == 0) { |
| 241 | return 0; |
| 242 | } |
| 243 | else if(underlyingStreamAvailable == 0) { |
| 244 | return bytesInBuffer; |
| 245 | } |
| 246 | else if(bytesInBuffer == buffer.length) { |
| 247 | return bytesInBuffer; |
| 248 | } |
| 249 | fillBuffer(); |
| 250 | return bytesInBuffer; |
| 251 | } |
| 252 | |
| 253 | @Override |
| 254 | @SuppressWarnings("NullableProblems") //I can't find the correct way to fix this! |
| 255 | public int read(byte[] b, int off, int len) throws IOException { |
| 256 | if(inputStream.available() > 0) { |
| 257 | fillBuffer(); |
| 258 | } |
| 259 | if(bytesInBuffer == 0) { |
| 260 | return -1; |
| 261 | } |
| 262 | int bytesToCopy = Math.min(len, bytesInBuffer); |
| 263 | System.arraycopy(buffer, 0, b, off, bytesToCopy); |
| 264 | System.arraycopy(buffer, bytesToCopy, buffer, 0, buffer.length - bytesToCopy); |
| 265 | bytesInBuffer -= bytesToCopy; |
| 266 | return bytesToCopy; |
| 267 | } |
| 268 | |
| 269 | private void fillBuffer() throws IOException { |
| 270 | int readBytes = inputStream.read(workingBuffer, 0, Math.min(workingBuffer.length, buffer.length - bytesInBuffer)); |
| 271 | if(readBytes == -1) { |
| 272 | return; |
| 273 | } |
| 274 | for(int i = 0; i < readBytes; i++) { |
| 275 | if(workingBuffer[i] == COMMAND_IAC) { |
| 276 | i++; |
| 277 | if(Arrays.asList(COMMAND_DO, COMMAND_DONT, COMMAND_WILL, COMMAND_WONT).contains(workingBuffer[i])) { |
| 278 | parseCommand(workingBuffer, i, readBytes); |
| 279 | ++i; |
| 280 | continue; |
| 281 | } |
| 282 | else if(workingBuffer[i] == COMMAND_SUBNEGOTIATION) { //0xFA = SB = Subnegotiation |
| 283 | i += parseSubNegotiation(workingBuffer, ++i, readBytes); |
| 284 | continue; |
| 285 | } |
| 286 | else if(workingBuffer[i] != COMMAND_IAC) { //Double IAC = 255 |
| 287 | System.err.println("Unknown Telnet command: " + workingBuffer[i]); |
| 288 | } |
| 289 | } |
| 290 | buffer[bytesInBuffer++] = workingBuffer[i]; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | private void parseCommand(byte[] buffer, int position, int max) throws IOException { |
| 295 | if(position + 1 >= max) { |
| 296 | throw new IllegalStateException("State error, we got a command signal from the remote telnet client but " |
| 297 | + "not enough characters available in the stream"); |
| 298 | } |
| 299 | byte command = buffer[position]; |
| 300 | byte value = buffer[position + 1]; |
| 301 | switch(command) { |
| 302 | case COMMAND_DO: |
| 303 | case COMMAND_DONT: |
| 304 | if(value == OPTION_SUPPRESS_GO_AHEAD) { |
| 305 | negotiationState.suppressGoAhead = (command == COMMAND_DO); |
| 306 | eventListener.requestReply(command == COMMAND_DO, value); |
| 307 | } |
| 308 | else if(value == OPTION_EXTEND_ASCII) { |
| 309 | negotiationState.extendedAscii = (command == COMMAND_DO); |
| 310 | eventListener.requestReply(command == COMMAND_DO, value); |
| 311 | } |
| 312 | else { |
| 313 | negotiationState.onUnsupportedRequestCommand(command == COMMAND_DO, value); |
| 314 | } |
| 315 | break; |
| 316 | case COMMAND_WILL: |
| 317 | case COMMAND_WONT: |
| 318 | if(value == OPTION_ECHO) { |
| 319 | negotiationState.clientEcho = (command == COMMAND_WILL); |
| 320 | } |
| 321 | else if(value == OPTION_LINEMODE) { |
| 322 | negotiationState.clientLineMode0 = (command == COMMAND_WILL); |
| 323 | } |
| 324 | else if(value == OPTION_NAWS) { |
| 325 | negotiationState.clientResizeNotification = (command == COMMAND_WILL); |
| 326 | } |
| 327 | else { |
| 328 | negotiationState.onUnsupportedStateCommand(command == COMMAND_WILL, value); |
| 329 | } |
| 330 | break; |
| 331 | default: |
| 332 | throw new UnsupportedOperationException("No command handler implemented for " + TelnetProtocol.CODE_TO_NAME.get(command)); |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | private int parseSubNegotiation(byte[] buffer, int position, int max) { |
| 337 | int originalPosition = position; |
| 338 | |
| 339 | //Read operation |
| 340 | byte operation = buffer[position++]; |
| 341 | |
| 342 | //Read until [IAC SE] |
| 343 | ByteArrayOutputStream outputBuffer = new ByteArrayOutputStream(); |
| 344 | while(position < max) { |
| 345 | byte read = buffer[position]; |
| 346 | if(read != COMMAND_IAC) { |
| 347 | outputBuffer.write(read); |
| 348 | } |
| 349 | else { |
| 350 | if(position + 1 == max) { |
| 351 | throw new IllegalStateException("State error, unexpected end of buffer when reading subnegotiation"); |
| 352 | } |
| 353 | position++; |
| 354 | if(buffer[position] == COMMAND_IAC) { |
| 355 | outputBuffer.write(COMMAND_IAC); //Escaped IAC |
| 356 | } |
| 357 | else if(buffer[position] == COMMAND_SUBNEGOTIATION_END) { |
| 358 | parseSubNegotiation(operation, outputBuffer.toByteArray()); |
| 359 | return ++position - originalPosition; |
| 360 | } |
| 361 | } |
| 362 | position++; |
| 363 | } |
| 364 | throw new IllegalStateException("State error, unexpected end of buffer when reading subnegotiation, no IAC SE"); |
| 365 | } |
| 366 | |
| 367 | private void parseSubNegotiation(byte option, byte[] additionalData) { |
| 368 | switch(option) { |
| 369 | case OPTION_NAWS: |
| 370 | eventListener.onResize( |
| 371 | convertTwoBytesToInt2(additionalData[1], additionalData[0]), |
| 372 | convertTwoBytesToInt2(additionalData[3], additionalData[2])); |
| 373 | break; |
| 374 | case OPTION_LINEMODE: |
| 375 | //We don't parse this, as this is a very complicated command :( |
| 376 | //Let's leave it for now, fingers crossed |
| 377 | break; |
| 378 | default: |
| 379 | negotiationState.onUnsupportedSubnegotiation(option, additionalData); |
| 380 | break; |
| 381 | } |
| 382 | } |
| 383 | } |
| 384 | |
| 385 | private static int convertTwoBytesToInt2(byte b1, byte b2) { |
| 386 | return ( (b2 & 0xFF) << 8) | (b1 & 0xFF); |
| 387 | } |
| 388 | } |