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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 | int writeRC; | |
112 | int writeLastErrno; | |
113 | boolean writeLastError; | |
114 | boolean writeCR; | |
115 | ||
116 | /** | |
117 | * Constuctor calls reset(). | |
118 | */ | |
119 | public TelnetState() { | |
120 | reset(); | |
121 | } | |
122 | ||
123 | /** | |
124 | * Reset NVT to default state as per RFC 854. | |
125 | */ | |
126 | public void reset() { | |
127 | echoMode = false; | |
128 | binaryMode = false; | |
129 | goAhead = true; | |
130 | doTermType = true; | |
131 | doTermSpeed = true; | |
132 | doNAWS = true; | |
133 | doEnvironment = true; | |
134 | doInit = true; | |
135 | isServer = true; | |
136 | ||
137 | iac = false; | |
138 | dowill = false; | |
139 | subnegEnd = false; | |
140 | isEof = false; | |
141 | eofMsg = false; | |
142 | readCR = false; | |
143 | ||
144 | writeRC = 0; | |
145 | writeLastErrno = 0; | |
146 | writeLastError = false; | |
147 | writeCR = false; | |
148 | ||
149 | } | |
150 | } | |
151 | ||
152 | /** | |
153 | * State of the protocol. Note package private access. | |
154 | */ | |
155 | TelnetState nvt; | |
156 | ||
157 | /** | |
158 | * See if telnet server/client is in ASCII mode. | |
159 | * | |
160 | * @return if true, this connection is in ASCII mode | |
161 | */ | |
162 | public boolean isAscii() { | |
163 | return (!nvt.binaryMode); | |
164 | } | |
165 | ||
166 | /** | |
167 | * Creates a Socket that knows the telnet protocol. | |
168 | * | |
169 | * @param socket the underlying Socket | |
170 | */ | |
171 | TelnetSocket(Socket socket) throws IOException { | |
172 | super(); | |
173 | nvt = new TelnetState(); | |
174 | this.socket = socket; | |
175 | } | |
176 | ||
177 | // Socket interface ------------------------------------------------------- | |
178 | ||
179 | /** | |
180 | * Returns an input stream for this socket. | |
181 | * | |
182 | * @return the input stream | |
183 | */ | |
184 | @Override | |
185 | public InputStream getInputStream() throws IOException { | |
186 | if (input == null) { | |
187 | input = new TelnetInputStream(this, super.getInputStream()); | |
188 | } | |
189 | return input; | |
190 | } | |
191 | ||
192 | /** | |
193 | * Returns an output stream for this socket. | |
194 | * | |
195 | * @return the output stream | |
196 | */ | |
197 | @Override | |
198 | public OutputStream getOutputStream() throws IOException { | |
199 | if (output == null) { | |
200 | output = new TelnetOutputStream(this, super.getOutputStream()); | |
201 | } | |
202 | return output; | |
203 | } | |
204 | ||
205 | } |