Rev Author Line No. Line
3328 povik 1 /**
2 * \addtogroup exampleapps
3 * @{
4 */
5  
6 /**
7 * \defgroup telnetd Telnet server
8 * @{
9 *
10 * The uIP telnet server provides a command based interface to uIP. It
11 * allows using the "telnet" application to access uIP, and implements
12 * the required telnet option negotiation.
13 *
14 * The code is structured in a way which makes it possible to add
15 * commands without having to rewrite the main telnet code. The main
16 * telnet code calls two callback functions, telnetd_connected() and
17 * telnetd_input(), when a telnet connection has been established and
18 * when a line of text arrives on a telnet connection. These two
19 * functions can be implemented in a way which suits the particular
20 * application or environment in which the uIP system is intended to
21 * be run.
22 *
23 * The uIP distribution contains an example telnet shell
24 * implementation that provides a basic set of commands.
25 */
26  
27 /**
28 * \file
29 * Implementation of the Telnet server.
30 * \author Adam Dunkels <adam@dunkels.com>
31 */
32  
33 /*
34 * Copyright (c) 2003, Adam Dunkels.
35 * All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 * notice, this list of conditions and the following disclaimer in the
44 * documentation and/or other materials provided with the distribution.
45 * 3. The name of the author may not be used to endorse or promote
46 * products derived from this software without specific prior
47 * written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
50 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
51 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
53 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
55 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
57 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
58 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
59 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
60 *
61 * This file is part of the uIP TCP/IP stack.
62 *
63 * $Id: telnetd.c,v 1.1.2.2 2003/10/07 13:47:50 adam Exp $
64 *
65 */
66  
67 #include "uip.h"
68 #include "memb.h"
69 #include "telnetd.h"
70 #include <string.h>
71  
72 #define ISO_nl 0x0a
73 #define ISO_cr 0x0d
74  
75 MEMB(linemem, TELNETD_LINELEN, TELNETD_NUMLINES);
76  
77 static u8_t i;
78  
79 #define STATE_NORMAL 0
80 #define STATE_IAC 1
81 #define STATE_WILL 2
82 #define STATE_WONT 3
83 #define STATE_DO 4
84 #define STATE_DONT 5
85 #define STATE_CLOSE 6
86  
87 #define TELNET_IAC 255
88 #define TELNET_WILL 251
89 #define TELNET_WONT 252
90 #define TELNET_DO 253
91 #define TELNET_DONT 254
92 /*-----------------------------------------------------------------------------------*/
93 static char *
94 alloc_line(void)
95 {
96 return memb_alloc(&linemem);
97 }
98 /*-----------------------------------------------------------------------------------*/
99 static void
100 dealloc_line(char *line)
101 {
102 memb_free(&linemem, line);
103 }
104 /*-----------------------------------------------------------------------------------*/
105 static void
106 sendline(struct telnetd_state *s, char *line)
107 {
108 static unsigned int i;
109 for(i = 0; i < TELNETD_NUMLINES; ++i) {
110 if(s->lines[i] == NULL) {
111 s->lines[i] = line;
112 break;
113 }
114 }
115 if(i == TELNETD_NUMLINES) {
116 dealloc_line(line);
117 }
118 }
119 /*-----------------------------------------------------------------------------------*/
120 /**
121 * Close a telnet session.
122 *
123 * This function can be called from a telnet command in order to close
124 * the connection.
125 *
126 * \param s The connection which is to be closed.
127 *
128 */
129 /*-----------------------------------------------------------------------------------*/
130 void
131 telnetd_close(struct telnetd_state *s)
132 {
133 s->state = STATE_CLOSE;
134 }
135 /*-----------------------------------------------------------------------------------*/
136 /**
137 * Print a prompt on a telnet connection.
138 *
139 * This function can be called by the telnet command shell in order to
140 * print out a command prompt.
141 *
142 * \param s A telnet connection.
143 *
144 * \param str The command prompt.
145 *
146 */
147 /*-----------------------------------------------------------------------------------*/
148 void
149 telnetd_prompt(struct telnetd_state *s, char *str)
150 {
151 char *line;
152 line = alloc_line();
153 if(line != NULL) {
154 strncpy(line, str, TELNETD_LINELEN);
155 sendline(s, line);
156 }
157 }
158 /*-----------------------------------------------------------------------------------*/
159 /**
160 * Print out a string on a telnet connection.
161 *
162 * This function can be called from a telnet command parser in order
163 * to print out a string of text on the connection. The two strings
164 * given as arguments to the function will be concatenated, a carrige
165 * return and a new line character will be added, and the line is
166 * sent.
167 *
168 * \param s The telnet connection.
169 *
170 * \param str1 The first string.
171 *
172 * \param str2 The second string.
173 *
174 */
175 /*-----------------------------------------------------------------------------------*/
176 void
177 telnetd_output(struct telnetd_state *s, char *str1, char *str2)
178 {
179 static unsigned len;
180 char *line;
181  
182 line = alloc_line();
183 if(line != NULL) {
184 len = strlen(str1);
185 strncpy(line, str1, TELNETD_LINELEN);
186 if(len < TELNETD_LINELEN) {
187 strncpy(line + len, str2, TELNETD_LINELEN - len);
188 }
189 len = strlen(line);
190 if(len < TELNETD_LINELEN - 2) {
191 line[len] = ISO_cr;
192 line[len+1] = ISO_nl;
193 line[len+2] = 0;
194 }
195 sendline(s, line);
196 }
197 }
198 /*-----------------------------------------------------------------------------------*/
199 /**
200 * Initialize the telnet server.
201 *
202 * This function will perform the necessary initializations and start
203 * listening on TCP port 23.
204 */
205 /*-----------------------------------------------------------------------------------*/
206 void
207 telnetd_init(void)
208 {
209 memb_init(&linemem);
210 uip_listen(HTONS(23));
211 }
212 /*-----------------------------------------------------------------------------------*/
213 static void
214 acked(struct telnetd_state *s)
215 {
216 dealloc_line(s->lines[0]);
217 for(i = 1; i < TELNETD_NUMLINES; ++i) {
218 s->lines[i - 1] = s->lines[i];
219 }
220 }
221 /*-----------------------------------------------------------------------------------*/
222 static void
223 senddata(struct telnetd_state *s)
224 {
225 if(s->lines[0] != NULL) {
226 uip_send(s->lines[0], strlen(s->lines[0]));
227 }
228 }
229 /*-----------------------------------------------------------------------------------*/
230 static void
231 getchar(struct telnetd_state *s, u8_t c)
232 {
233 if(c == ISO_cr) {
234 return;
235 }
236  
237 s->buf[(int)s->bufptr] = c;
238 if(s->buf[(int)s->bufptr] == ISO_nl ||
239 s->bufptr == sizeof(s->buf) - 1) {
240 if(s->bufptr > 0) {
241 s->buf[(int)s->bufptr] = 0;
242 }
243 telnetd_input(s, s->buf);
244 s->bufptr = 0;
245 } else {
246 ++s->bufptr;
247 }
248 }
249 /*-----------------------------------------------------------------------------------*/
250 static void
251 sendopt(struct telnetd_state *s, u8_t option, u8_t value)
252 {
253 char *line;
254 line = alloc_line();
255 if(line != NULL) {
256 line[0] = TELNET_IAC;
257 line[1] = option;
258 line[2] = value;
259 line[3] = 0;
260 sendline(s, line);
261 }
262 }
263 /*-----------------------------------------------------------------------------------*/
264 static void
265 newdata(struct telnetd_state *s)
266 {
267 u16_t len;
268 u8_t c;
269  
270  
271 len = uip_datalen();
272  
273 while(len > 0 && s->bufptr < sizeof(s->buf)) {
274 c = *uip_appdata;
275 ++uip_appdata;
276 --len;
277 switch(s->state) {
278 case STATE_IAC:
279 if(c == TELNET_IAC) {
280 getchar(s, c);
281 s->state = STATE_NORMAL;
282 } else {
283 switch(c) {
284 case TELNET_WILL:
285 s->state = STATE_WILL;
286 break;
287 case TELNET_WONT:
288 s->state = STATE_WONT;
289 break;
290 case TELNET_DO:
291 s->state = STATE_DO;
292 break;
293 case TELNET_DONT:
294 s->state = STATE_DONT;
295 break;
296 default:
297 s->state = STATE_NORMAL;
298 break;
299 }
300 }
301 break;
302 case STATE_WILL:
303 /* Reply with a DONT */
304 sendopt(s, TELNET_DONT, c);
305 s->state = STATE_NORMAL;
306 break;
307  
308 case STATE_WONT:
309 /* Reply with a DONT */
310 sendopt(s, TELNET_DONT, c);
311 s->state = STATE_NORMAL;
312 break;
313 case STATE_DO:
314 /* Reply with a WONT */
315 sendopt(s, TELNET_WONT, c);
316 s->state = STATE_NORMAL;
317 break;
318 case STATE_DONT:
319 /* Reply with a WONT */
320 sendopt(s, TELNET_WONT, c);
321 s->state = STATE_NORMAL;
322 break;
323 case STATE_NORMAL:
324 if(c == TELNET_IAC) {
325 s->state = STATE_IAC;
326 } else {
327 getchar(s, c);
328 }
329 break;
330 }
331  
332  
333 }
334  
335 }
336 /*-----------------------------------------------------------------------------------*/
337 void
338 telnetd_app(void)
339 {
340 struct telnetd_state *s;
341  
342 s = (struct telnetd_state *)uip_conn->appstate;
343  
344 if(uip_connected()) {
345  
346 for(i = 0; i < TELNETD_NUMLINES; ++i) {
347 s->lines[i] = NULL;
348 }
349 s->bufptr = 0;
350 s->state = STATE_NORMAL;
351  
352 telnetd_connected(s);
353 senddata(s);
354 return;
355 }
356  
357 if(s->state == STATE_CLOSE) {
358 s->state = STATE_NORMAL;
359 uip_close();
360 return;
361 }
362  
363 if(uip_closed()) {
364 telnetd_output(s, "Connection closed", "");
365 }
366  
367  
368 if(uip_aborted()) {
369 telnetd_output(s, "Connection reset", "");
370 }
371  
372 if(uip_timedout()) {
373 telnetd_output(s, "Connection timed out", "");
374 }
375  
376 if(uip_acked()) {
377 acked(s);
378 }
379  
380 if(uip_newdata()) {
381 newdata(s);
382 }
383  
384 if(uip_rexmit() ||
385 uip_newdata() ||
386 uip_acked()) {
387 senddata(s);
388 } else if(uip_poll()) {
389 senddata(s);
390 }
391 }
392 /*-----------------------------------------------------------------------------------*/