2 * Copyright (c) 1989, 1993
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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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29 * @(#)termstat.c 8.2 (Berkeley) 5/30/95
30 * $FreeBSD: src/crypto/telnet/telnetd/termstat.c,v 1.4.2.4 2002/04/13 10:59:09 markm Exp $
36 #include <libtelnet/encrypt.h>
42 int def_tspeed
= -1, def_rspeed
= -1;
44 int def_row
= 0, def_col
= 0;
47 static int _terminit
= 0;
54 * This function handles all management of linemode.
56 * Linemode allows the client to do the local editing of data
57 * and send only complete lines to the server. Linemode state is
58 * based on the state of the pty driver. If the pty is set for
59 * external processing, then we can use linemode. Further, if we
60 * can use real linemode, then we can look at the edit control bits
61 * in the pty to determine what editing the client should do.
63 * Linemode support uses the following state flags to keep track of
64 * current and desired linemode state.
65 * alwayslinemode : true if -l was specified on the telnetd
66 * command line. It means to have linemode on as much as
69 * lmodetype: signifies whether the client can
70 * handle real linemode, or if use of kludgeomatic linemode
71 * is preferred. It will be set to one of the following:
72 * REAL_LINEMODE : use linemode option
73 * NO_KLUDGE : don't initiate kludge linemode.
74 * KLUDGE_LINEMODE : use kludge linemode
75 * NO_LINEMODE : client is ignorant of linemode
77 * linemode, uselinemode : linemode is true if linemode
78 * is currently on, uselinemode is the state that we wish
79 * to be in. If another function wishes to turn linemode
80 * on or off, it sets or clears uselinemode.
82 * editmode, useeditmode : like linemode/uselinemode, but
83 * these contain the edit mode states (edit and trapsig).
85 * The state variables correspond to some of the state information
88 * In real linemode, this corresponds to whether the pty
89 * expects external processing of incoming data.
90 * In kludge linemode, this more closely corresponds to the
91 * whether normal processing is on or not. (ICANON in
92 * system V, or COOKED mode in BSD.)
93 * If the -l option was specified (alwayslinemode), then
94 * an attempt is made to force external processing on at
97 * The following heuristics are applied to determine linemode
98 * handling within the server.
99 * 1) Early on in starting up the server, an attempt is made
100 * to negotiate the linemode option. If this succeeds
101 * then lmodetype is set to REAL_LINEMODE and all linemode
102 * processing occurs in the context of the linemode option.
103 * 2) If the attempt to negotiate the linemode option failed,
104 * and the "-k" (don't initiate kludge linemode) isn't set,
105 * then we try to use kludge linemode. We test for this
106 * capability by sending "do Timing Mark". If a positive
107 * response comes back, then we assume that the client
108 * understands kludge linemode (ech!) and the
109 * lmodetype flag is set to KLUDGE_LINEMODE.
110 * 3) Otherwise, linemode is not supported at all and
111 * lmodetype remains set to NO_LINEMODE (which happens
112 * to be 0 for convenience).
113 * 4) At any time a command arrives that implies a higher
114 * state of linemode support in the client, we move to that
117 * A short explanation of kludge linemode is in order here.
118 * 1) The heuristic to determine support for kludge linemode
119 * is to send a do timing mark. We assume that a client
120 * that supports timing marks also supports kludge linemode.
121 * A risky proposition at best.
122 * 2) Further negotiation of linemode is done by changing the
123 * the server's state regarding SGA. If server will SGA,
124 * then linemode is off, if server won't SGA, then linemode
130 int need_will_echo
= 0;
133 * Check for changes to flow control if client supports it.
138 * Check linemode on/off state
140 uselinemode
= tty_linemode();
143 * If alwayslinemode is on, and pty is changing to turn it off, then
144 * force linemode back on.
146 if (alwayslinemode
&& linemode
&& !uselinemode
) {
148 tty_setlinemode(uselinemode
);
153 * Check for state of BINARY options.
155 * We only need to do the binary dance if we are actually going
156 * to use linemode. As this confuses some telnet clients
157 * that don't support linemode, and doesn't gain us
158 * anything, we don't do it unless we're doing linemode.
159 * -Crh (henrich@msu.edu)
162 if (tty_isbinaryin()) {
163 if (his_want_state_is_wont(TELOPT_BINARY
))
164 send_do(TELOPT_BINARY
, 1);
166 if (his_want_state_is_will(TELOPT_BINARY
))
167 send_dont(TELOPT_BINARY
, 1);
170 if (tty_isbinaryout()) {
171 if (my_want_state_is_wont(TELOPT_BINARY
))
172 send_will(TELOPT_BINARY
, 1);
174 if (my_want_state_is_will(TELOPT_BINARY
))
175 send_wont(TELOPT_BINARY
, 1);
181 * If the terminal is not echoing, but editing is enabled,
182 * something like password input is going to happen, so
183 * if we the other side is not currently sending encrypted
184 * data, ask the other side to start encrypting.
186 if (his_state_is_will(TELOPT_ENCRYPT
)) {
187 static int enc_passwd
= 0;
188 if (uselinemode
&& !tty_isecho() && tty_isediting()
189 && (enc_passwd
== 0) && !decrypt_input
) {
190 encrypt_send_request_start();
192 } else if (enc_passwd
) {
193 encrypt_send_request_end();
197 #endif /* ENCRYPTION */
200 * Do echo mode handling as soon as we know what the
201 * linemode is going to be.
202 * If the pty has echo turned off, then tell the client that
203 * the server will echo. If echo is on, then the server
204 * will echo if in character mode, but in linemode the
205 * client should do local echoing. The state machine will
206 * not send anything if it is unnecessary, so don't worry
209 * If we need to send the WILL ECHO (because echo is off),
210 * then delay that until after we have changed the MODE.
211 * This way, when the user is turning off both editing
212 * and echo, the client will get editing turned off first.
213 * This keeps the client from going into encryption mode
214 * and then right back out if it is doing auto-encryption
215 * when passwords are being typed.
219 send_wont(TELOPT_ECHO
, 1);
222 #ifdef KLUDGELINEMODE
223 if (lmodetype
== KLUDGE_OK
)
224 lmodetype
= KLUDGE_LINEMODE
;
229 * If linemode is being turned off, send appropriate
230 * command and then we're all done.
232 if (!uselinemode
&& linemode
) {
233 # ifdef KLUDGELINEMODE
234 if (lmodetype
== REAL_LINEMODE
) {
235 # endif /* KLUDGELINEMODE */
236 send_dont(TELOPT_LINEMODE
, 1);
237 # ifdef KLUDGELINEMODE
238 } else if (lmodetype
== KLUDGE_LINEMODE
)
239 send_will(TELOPT_SGA
, 1);
240 # endif /* KLUDGELINEMODE */
241 send_will(TELOPT_ECHO
, 1);
242 linemode
= uselinemode
;
246 # ifdef KLUDGELINEMODE
248 * If using real linemode check edit modes for possible later use.
249 * If we are in kludge linemode, do the SGA negotiation.
251 if (lmodetype
== REAL_LINEMODE
) {
252 # endif /* KLUDGELINEMODE */
255 useeditmode
|= MODE_EDIT
;
257 useeditmode
|= MODE_TRAPSIG
;
259 useeditmode
|= MODE_SOFT_TAB
;
261 useeditmode
|= MODE_LIT_ECHO
;
262 # ifdef KLUDGELINEMODE
263 } else if (lmodetype
== KLUDGE_LINEMODE
) {
264 if (tty_isediting() && uselinemode
)
265 send_wont(TELOPT_SGA
, 1);
267 send_will(TELOPT_SGA
, 1);
269 # endif /* KLUDGELINEMODE */
272 * Negotiate linemode on if pty state has changed to turn it on.
273 * Send appropriate command and send along edit mode, then all done.
275 if (uselinemode
&& !linemode
) {
276 # ifdef KLUDGELINEMODE
277 if (lmodetype
== KLUDGE_LINEMODE
) {
278 send_wont(TELOPT_SGA
, 1);
279 } else if (lmodetype
== REAL_LINEMODE
) {
280 # endif /* KLUDGELINEMODE */
281 send_do(TELOPT_LINEMODE
, 1);
282 /* send along edit modes */
283 output_data("%c%c%c%c%c%c%c", IAC
, SB
,
284 TELOPT_LINEMODE
, LM_MODE
, useeditmode
,
286 editmode
= useeditmode
;
287 # ifdef KLUDGELINEMODE
289 # endif /* KLUDGELINEMODE */
290 linemode
= uselinemode
;
294 # ifdef KLUDGELINEMODE
296 * None of what follows is of any value if not using
299 if (lmodetype
< REAL_LINEMODE
)
301 # endif /* KLUDGELINEMODE */
303 if (linemode
&& his_state_is_will(TELOPT_LINEMODE
)) {
305 * If edit mode changed, send edit mode.
307 if (useeditmode
!= editmode
) {
309 * Send along appropriate edit mode mask.
311 output_data("%c%c%c%c%c%c%c", IAC
, SB
,
312 TELOPT_LINEMODE
, LM_MODE
, useeditmode
,
314 editmode
= useeditmode
;
319 * Check for changes to special characters in use.
328 send_will(TELOPT_ECHO
, 1);
330 * Some things should be deferred until after the pty state has
331 * been set by the local process. Do those things that have been
332 * deferred now. This only happens once.
334 if (_terminit
== 0) {
343 } /* end of localstat */
344 #endif /* LINEMODE */
349 * Check for changes to flow control
354 if (his_state_is_will(TELOPT_LFLOW
)) {
355 if (tty_flowmode() != flowmode
) {
356 flowmode
= tty_flowmode();
357 output_data("%c%c%c%c%c%c",
358 IAC
, SB
, TELOPT_LFLOW
,
359 flowmode
? LFLOW_ON
: LFLOW_OFF
,
362 if (tty_restartany() != restartany
) {
363 restartany
= tty_restartany();
364 output_data("%c%c%c%c%c%c",
365 IAC
, SB
, TELOPT_LFLOW
,
366 restartany
? LFLOW_RESTART_ANY
376 * Process linemode related requests from the client.
377 * Client can request a change to only one of linemode, editmode or slc's
378 * at a time, and if using kludge linemode, then only linemode may be
382 clientstat(int code
, int parm1
, int parm2
)
386 * Get a copy of terminal characteristics.
391 * Process request from client. code tells what it is.
395 case TELOPT_LINEMODE
:
397 * Don't do anything unless client is asking us to change
400 uselinemode
= (parm1
== WILL
);
401 if (uselinemode
!= linemode
) {
402 # ifdef KLUDGELINEMODE
404 * If using kludge linemode, make sure that
405 * we can do what the client asks.
406 * We can not turn off linemode if alwayslinemode
407 * and the ICANON bit is set.
409 if (lmodetype
== KLUDGE_LINEMODE
) {
410 if (alwayslinemode
&& tty_isediting()) {
416 * Quit now if we can't do it.
418 if (uselinemode
== linemode
)
422 * If using real linemode and linemode is being
423 * turned on, send along the edit mode mask.
425 if (lmodetype
== REAL_LINEMODE
&& uselinemode
)
426 # else /* KLUDGELINEMODE */
428 # endif /* KLUDGELINEMODE */
432 useeditmode
|= MODE_EDIT
;
434 useeditmode
|= MODE_TRAPSIG
;
436 useeditmode
|= MODE_SOFT_TAB
;
438 useeditmode
|= MODE_LIT_ECHO
;
439 output_data("%c%c%c%c%c%c%c", IAC
,
440 SB
, TELOPT_LINEMODE
, LM_MODE
,
441 useeditmode
, IAC
, SE
);
442 editmode
= useeditmode
;
446 tty_setlinemode(uselinemode
);
448 linemode
= uselinemode
;
451 send_will(TELOPT_ECHO
, 1);
460 * Client has sent along a mode mask. If it agrees with
461 * what we are currently doing, ignore it; if not, it could
462 * be viewed as a request to change. Note that the server
463 * will change to the modes in an ack if it is different from
464 * what we currently have, but we will not ack the ack.
466 useeditmode
&= MODE_MASK
;
467 ack
= (useeditmode
& MODE_ACK
);
468 useeditmode
&= ~MODE_ACK
;
470 if ((changed
= (useeditmode
^ editmode
))) {
472 * This check is for a timing problem. If the
473 * state of the tty has changed (due to the user
474 * application) we need to process that info
475 * before we write in the state contained in the
476 * ack!!! This gets out the new MODE request,
477 * and when the ack to that command comes back
478 * we'll set it and be in the right mode.
482 if (changed
& MODE_EDIT
)
483 tty_setedit(useeditmode
& MODE_EDIT
);
485 if (changed
& MODE_TRAPSIG
)
486 tty_setsig(useeditmode
& MODE_TRAPSIG
);
488 if (changed
& MODE_SOFT_TAB
)
489 tty_setsofttab(useeditmode
& MODE_SOFT_TAB
);
491 if (changed
& MODE_LIT_ECHO
)
492 tty_setlitecho(useeditmode
& MODE_LIT_ECHO
);
497 output_data("%c%c%c%c%c%c%c", IAC
,
498 SB
, TELOPT_LINEMODE
, LM_MODE
,
499 useeditmode
|MODE_ACK
,
503 editmode
= useeditmode
;
508 } /* end of case LM_MODE */
509 #endif /* LINEMODE */
520 * Defer changing window size until after terminal is
525 #endif /* LINEMODE */
528 * Change window size as requested by client.
533 (void) ioctl(pty
, TIOCSWINSZ
, (char *)&ws
);
535 #endif /* TIOCSWINSZ */
545 * Defer changing the terminal speed.
549 #endif /* LINEMODE */
551 * Change terminal speed as requested by client.
552 * We set the receive speed first, so that if we can't
553 * store separate receive and transmit speeds, the transmit
554 * speed will take precedence.
562 } /* end of case TELOPT_TSPEED */
567 } /* end of switch */
571 } /* end of clientstat */
577 * Some things should not be done until after the login process has started
578 * and all the pty modes are set to what they are supposed to be. This
579 * function is called when the pty state has been processed for the first time.
580 * It calls other functions that do things that were deferred in each module.
587 * local stuff that got deferred.
589 if (def_tspeed
!= -1) {
590 clientstat(TELOPT_TSPEED
, def_tspeed
, def_rspeed
);
591 def_tspeed
= def_rspeed
= 0;
595 if (def_col
|| def_row
) {
598 memset((char *)&ws
, 0, sizeof(ws
));
601 (void) ioctl(pty
, TIOCSWINSZ
, (char *)&ws
);
606 * The only other module that currently defers anything.
610 } /* end of defer_terminit */
615 * Returns true if the pty state has been processed yet.
622 } /* end of terminit */
623 #endif /* LINEMODE */