001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.telnet;
019
020/**
021 * The TelnetOption class cannot be instantiated and only serves as a storehouse for telnet option constants.
022 * <p>
023 * Details regarding Telnet option specification can be found in RFC 855.
024 * </p>
025 *
026 * @see org.apache.commons.net.telnet.Telnet
027 * @see org.apache.commons.net.telnet.TelnetClient
028 */
029public class TelnetOption {
030    /** The maximum value an option code can have. This value is 255. */
031    public static final int MAX_OPTION_VALUE = 255;
032
033    /**
034     * {@value}
035     */
036    public static final int BINARY = 0;
037
038    /**
039     * {@value}
040     */
041    public static final int ECHO = 1;
042
043    /**
044     * {@value}
045     */
046    public static final int PREPARE_TO_RECONNECT = 2;
047
048    /**
049     * {@value}
050     */
051    public static final int SUPPRESS_GO_AHEAD = 3;
052
053    /**
054     * {@value}
055     */
056    public static final int APPROXIMATE_MESSAGE_SIZE = 4;
057
058    /**
059     * {@value}
060     */
061    public static final int STATUS = 5;
062
063    /**
064     * {@value}
065     */
066    public static final int TIMING_MARK = 6;
067
068    /**
069     * {@value}
070     */
071    public static final int REMOTE_CONTROLLED_TRANSMISSION = 7;
072
073    /**
074     * {@value}
075     */
076    public static final int NEGOTIATE_OUTPUT_LINE_WIDTH = 8;
077
078    /**
079     * {@value}
080     */
081    public static final int NEGOTIATE_OUTPUT_PAGE_SIZE = 9;
082
083    /**
084     * {@value}
085     */
086    public static final int NEGOTIATE_CARRIAGE_RETURN = 10;
087
088    /**
089     * {@value}
090     */
091    public static final int NEGOTIATE_HORIZONTAL_TAB_STOP = 11;
092
093    /**
094     * {@value}
095     */
096    public static final int NEGOTIATE_HORIZONTAL_TAB = 12;
097
098    /**
099     * {@value}
100     */
101    public static final int NEGOTIATE_FORMFEED = 13;
102
103    /**
104     * {@value}
105     */
106    public static final int NEGOTIATE_VERTICAL_TAB_STOP = 14;
107
108    /**
109     * {@value}
110     */
111    public static final int NEGOTIATE_VERTICAL_TAB = 15;
112
113    /**
114     * {@value}
115     */
116    public static final int NEGOTIATE_LINEFEED = 16;
117
118    /**
119     * {@value}
120     */
121    public static final int EXTENDED_ASCII = 17;
122
123    /**
124     * {@value}
125     */
126    public static final int FORCE_LOGOUT = 18;
127
128    /**
129     * {@value}
130     */
131    public static final int BYTE_MACRO = 19;
132
133    /**
134     * {@value}
135     */
136    public static final int DATA_ENTRY_TERMINAL = 20;
137
138    /**
139     * {@value}
140     */
141    public static final int SUPDUP = 21;
142
143    /**
144     * {@value}
145     */
146    public static final int SUPDUP_OUTPUT = 22;
147
148    /**
149     * {@value}
150     */
151    public static final int SEND_LOCATION = 23;
152
153    /**
154     * {@value}
155     */
156    public static final int TERMINAL_TYPE = 24;
157
158    /**
159     * {@value}
160     */
161    public static final int END_OF_RECORD = 25;
162
163    /**
164     * {@value}
165     */
166    public static final int TACACS_USER_IDENTIFICATION = 26;
167
168    /**
169     * {@value}
170     */
171    public static final int OUTPUT_MARKING = 27;
172
173    /**
174     * {@value}
175     */
176    public static final int TERMINAL_LOCATION_NUMBER = 28;
177
178    /**
179     * {@value}
180     */
181    public static final int REGIME_3270 = 29;
182
183    /**
184     * {@value}
185     */
186    public static final int X3_PAD = 30;
187
188    /**
189     * {@value}
190     */
191    public static final int WINDOW_SIZE = 31;
192
193    /**
194     * {@value}
195     */
196    public static final int TERMINAL_SPEED = 32;
197
198    /**
199     * {@value}
200     */
201    public static final int REMOTE_FLOW_CONTROL = 33;
202
203    /**
204     * {@value}
205     */
206    public static final int LINEMODE = 34;
207
208    /**
209     * {@value}
210     */
211    public static final int X_DISPLAY_LOCATION = 35;
212
213    /**
214     * {@value}
215     */
216    public static final int OLD_ENVIRONMENT_VARIABLES = 36;
217
218    /**
219     * {@value}
220     */
221    public static final int AUTHENTICATION = 37;
222
223    /**
224     * {@value}
225     */
226    public static final int ENCRYPTION = 38;
227
228    /**
229     * {@value}
230     */
231    public static final int NEW_ENVIRONMENT_VARIABLES = 39;
232
233    /**
234     * {@value}
235     */
236    public static final int EXTENDED_OPTIONS_LIST = 255;
237
238    /**
239     * {@value}
240     */
241    @SuppressWarnings("unused")
242    private static final int FIRST_OPTION = BINARY;
243
244    /**
245     * {@value}
246     */
247    private static final int LAST_OPTION = EXTENDED_OPTIONS_LIST;
248
249    /**
250     * {@value}
251     */
252    private static final String[] optionString = { "BINARY", "ECHO", "RCP", "SUPPRESS GO AHEAD", "NAME", "STATUS", "TIMING MARK", "RCTE", "NAOL", "NAOP",
253            "NAOCRD", "NAOHTS", "NAOHTD", "NAOFFD", "NAOVTS", "NAOVTD", "NAOLFD", "EXTEND ASCII", "LOGOUT", "BYTE MACRO", "DATA ENTRY TERMINAL", "SUPDUP",
254            "SUPDUP OUTPUT", "SEND LOCATION", "TERMINAL TYPE", "END OF RECORD", "TACACS UID", "OUTPUT MARKING", "TTYLOC", "3270 REGIME", "X.3 PAD", "NAWS",
255            "TSPEED", "LFLOW", "LINEMODE", "XDISPLOC", "OLD-ENVIRON", "AUTHENTICATION", "ENCRYPT", "NEW-ENVIRON", "TN3270E", "XAUTH", "CHARSET", "RSP",
256            "Com Port Control", "Suppress Local Echo", "Start TLS", "KERMIT", "SEND-URL", "FORWARD_X", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
257            "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
258            "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
259            "TELOPT PRAGMA LOGON", "TELOPT SSPI LOGON", "TELOPT PRAGMA HEARTBEAT", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
260            "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
261            "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
262            "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "Extended-Options-List" };
263
264    /**
265     * Returns the string representation of the telnet protocol option corresponding to the given option code.
266     *
267     * @param code The option code of the telnet protocol option
268     * @return The string representation of the telnet protocol option.
269     */
270    public static final String getOption(final int code) {
271        if (optionString[code].isEmpty()) {
272            return "UNASSIGNED";
273        }
274        return optionString[code];
275    }
276
277    /**
278     * Determines if a given option code is valid. Returns true if valid, false if not.
279     *
280     * @param code The option code to test.
281     * @return True if the option code is valid, false if not.
282     **/
283    public static final boolean isValidOption(final int code) {
284        return code <= LAST_OPTION;
285    }
286
287    /** Cannot be instantiated. */
288    private TelnetOption() {
289    }
290}