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HAMMER 60I/Many: Mirroring
[dragonfly.git] / libexec / telnetd / state.c
blob576eb12dcb9b53e19f7391560eb2accab538d683
1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)state.c 8.5 (Berkeley) 5/30/95
34 * $FreeBSD: src/libexec/telnetd/state.c,v 1.9.2.4 2002/04/13 11:07:12 markm Exp $
35 * $DragonFly: src/libexec/telnetd/state.c,v 1.3 2006/01/12 13:43:10 corecode Exp $
36 */
37
38 #include <stdarg.h>
39 #include "telnetd.h"
40
41 unsigned char doopt[] = { IAC, DO, '%', 'c', 0 };
42 unsigned char dont[] = { IAC, DONT, '%', 'c', 0 };
43 unsigned char will[] = { IAC, WILL, '%', 'c', 0 };
44 unsigned char wont[] = { IAC, WONT, '%', 'c', 0 };
45 int not42 = 1;
46
47 /*
48 * Buffer for sub-options, and macros
49 * for suboptions buffer manipulations
50 */
51 unsigned char subbuffer[512], *subpointer= subbuffer, *subend= subbuffer;
52
53 #define SB_CLEAR() subpointer = subbuffer
54 #define SB_TERM() { subend = subpointer; SB_CLEAR(); }
55 #define SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { \
56 *subpointer++ = (c); \
57 }
58 #define SB_GET() ((*subpointer++)&0xff)
59 #define SB_EOF() (subpointer >= subend)
60 #define SB_LEN() (subend - subpointer)
61
62 #ifdef ENV_HACK
63 unsigned char *subsave;
64 #define SB_SAVE() subsave = subpointer;
65 #define SB_RESTORE() subpointer = subsave;
66 #endif
67
68
69 /*
70 * State for recv fsm
71 */
72 #define TS_DATA 0 /* base state */
73 #define TS_IAC 1 /* look for double IAC's */
74 #define TS_CR 2 /* CR-LF ->'s CR */
75 #define TS_SB 3 /* throw away begin's... */
76 #define TS_SE 4 /* ...end's (suboption negotiation) */
77 #define TS_WILL 5 /* will option negotiation */
78 #define TS_WONT 6 /* wont " */
79 #define TS_DO 7 /* do " */
80 #define TS_DONT 8 /* dont " */
81
82 static void doclientstat(void);
83
84 void
85 telrcv(void)
86 {
87 int c;
88 static int state = TS_DATA;
89
90 while (ncc > 0) {
91 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
92 break;
93 c = *netip++ & 0377, ncc--;
94 switch (state) {
95
96 case TS_CR:
97 state = TS_DATA;
98 /* Strip off \n or \0 after a \r */
99 if ((c == 0) || (c == '\n')) {
100 break;
101 }
102 /* FALL THROUGH */
103
104 case TS_DATA:
105 if (c == IAC) {
106 state = TS_IAC;
107 break;
108 }
109 /*
110 * We now map \r\n ==> \r for pragmatic reasons.
111 * Many client implementations send \r\n when
112 * the user hits the CarriageReturn key.
113 *
114 * We USED to map \r\n ==> \n, since \r\n says
115 * that we want to be in column 1 of the next
116 * printable line, and \n is the standard
117 * unix way of saying that (\r is only good
118 * if CRMOD is set, which it normally is).
119 */
120 if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
121 int nc = *netip;
122 #ifdef LINEMODE
123 /*
124 * If we are operating in linemode,
125 * convert to local end-of-line.
126 */
127 if (linemode && (ncc > 0) && (('\n' == nc) ||
128 ((0 == nc) && tty_iscrnl())) ) {
129 netip++; ncc--;
130 c = '\n';
131 } else
132 #endif
133 {
134 state = TS_CR;
135 }
136 }
137 *pfrontp++ = c;
138 break;
139
140 case TS_IAC:
141 gotiac: switch (c) {
142
143 /*
144 * Send the process on the pty side an
145 * interrupt. Do this with a NULL or
146 * interrupt char; depending on the tty mode.
147 */
148 case IP:
149 DIAG(TD_OPTIONS,
150 printoption("td: recv IAC", c));
151 interrupt();
152 break;
153
154 case BREAK:
155 DIAG(TD_OPTIONS,
156 printoption("td: recv IAC", c));
157 sendbrk();
158 break;
159
160 /*
161 * Are You There?
162 */
163 case AYT:
164 DIAG(TD_OPTIONS,
165 printoption("td: recv IAC", c));
166 recv_ayt();
167 break;
168
169 /*
170 * Abort Output
171 */
172 case AO:
173 {
174 DIAG(TD_OPTIONS,
175 printoption("td: recv IAC", c));
176 ptyflush(); /* half-hearted */
177 init_termbuf();
178
179 if (slctab[SLC_AO].sptr &&
180 *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
181 *pfrontp++ =
182 (unsigned char)*slctab[SLC_AO].sptr;
183 }
184
185 netclear(); /* clear buffer back */
186 output_data("%c%c", IAC, DM);
187 neturg = nfrontp-1; /* off by one XXX */
188 DIAG(TD_OPTIONS,
189 printoption("td: send IAC", DM));
190 break;
191 }
192
193 /*
194 * Erase Character and
195 * Erase Line
196 */
197 case EC:
198 case EL:
199 {
200 cc_t ch;
201
202 DIAG(TD_OPTIONS,
203 printoption("td: recv IAC", c));
204 ptyflush(); /* half-hearted */
205 init_termbuf();
206 if (c == EC)
207 ch = *slctab[SLC_EC].sptr;
208 else
209 ch = *slctab[SLC_EL].sptr;
210 if (ch != (cc_t)(_POSIX_VDISABLE))
211 *pfrontp++ = (unsigned char)ch;
212 break;
213 }
214
215 /*
216 * Check for urgent data...
217 */
218 case DM:
219 DIAG(TD_OPTIONS,
220 printoption("td: recv IAC", c));
221 SYNCHing = stilloob(net);
222 settimer(gotDM);
223 break;
224
225
226 /*
227 * Begin option subnegotiation...
228 */
229 case SB:
230 state = TS_SB;
231 SB_CLEAR();
232 continue;
233
234 case WILL:
235 state = TS_WILL;
236 continue;
237
238 case WONT:
239 state = TS_WONT;
240 continue;
241
242 case DO:
243 state = TS_DO;
244 continue;
245
246 case DONT:
247 state = TS_DONT;
248 continue;
249 case EOR:
250 if (his_state_is_will(TELOPT_EOR))
251 doeof();
252 break;
253
254 /*
255 * Handle RFC 10xx Telnet linemode option additions
256 * to command stream (EOF, SUSP, ABORT).
257 */
258 case xEOF:
259 doeof();
260 break;
261
262 case SUSP:
263 sendsusp();
264 break;
265
266 case ABORT:
267 sendbrk();
268 break;
269
270 case IAC:
271 *pfrontp++ = c;
272 break;
273 }
274 state = TS_DATA;
275 break;
276
277 case TS_SB:
278 if (c == IAC) {
279 state = TS_SE;
280 } else {
281 SB_ACCUM(c);
282 }
283 break;
284
285 case TS_SE:
286 if (c != SE) {
287 if (c != IAC) {
288 /*
289 * bad form of suboption negotiation.
290 * handle it in such a way as to avoid
291 * damage to local state. Parse
292 * suboption buffer found so far,
293 * then treat remaining stream as
294 * another command sequence.
295 */
296
297 /* for DIAGNOSTICS */
298 SB_ACCUM(IAC);
299 SB_ACCUM(c);
300 subpointer -= 2;
301
302 SB_TERM();
303 suboption();
304 state = TS_IAC;
305 goto gotiac;
306 }
307 SB_ACCUM(c);
308 state = TS_SB;
309 } else {
310 /* for DIAGNOSTICS */
311 SB_ACCUM(IAC);
312 SB_ACCUM(SE);
313 subpointer -= 2;
314
315 SB_TERM();
316 suboption(); /* handle sub-option */
317 state = TS_DATA;
318 }
319 break;
320
321 case TS_WILL:
322 willoption(c);
323 state = TS_DATA;
324 continue;
325
326 case TS_WONT:
327 wontoption(c);
328 state = TS_DATA;
329 continue;
330
331 case TS_DO:
332 dooption(c);
333 state = TS_DATA;
334 continue;
335
336 case TS_DONT:
337 dontoption(c);
338 state = TS_DATA;
339 continue;
340
341 default:
342 syslog(LOG_ERR, "panic state=%d", state);
343 printf("telnetd: panic state=%d\n", state);
344 exit(1);
345 }
346 }
347 } /* end of telrcv */
348
349 /*
350 * The will/wont/do/dont state machines are based on Dave Borman's
351 * Telnet option processing state machine.
352 *
353 * These correspond to the following states:
354 * my_state = the last negotiated state
355 * want_state = what I want the state to go to
356 * want_resp = how many requests I have sent
357 * All state defaults are negative, and resp defaults to 0.
358 *
359 * When initiating a request to change state to new_state:
360 *
361 * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
362 * do nothing;
363 * } else {
364 * want_state = new_state;
365 * send new_state;
366 * want_resp++;
367 * }
368 *
369 * When receiving new_state:
370 *
371 * if (want_resp) {
372 * want_resp--;
373 * if (want_resp && (new_state == my_state))
374 * want_resp--;
375 * }
376 * if ((want_resp == 0) && (new_state != want_state)) {
377 * if (ok_to_switch_to new_state)
378 * want_state = new_state;
379 * else
380 * want_resp++;
381 * send want_state;
382 * }
383 * my_state = new_state;
384 *
385 * Note that new_state is implied in these functions by the function itself.
386 * will and do imply positive new_state, wont and dont imply negative.
387 *
388 * Finally, there is one catch. If we send a negative response to a
389 * positive request, my_state will be the positive while want_state will
390 * remain negative. my_state will revert to negative when the negative
391 * acknowlegment arrives from the peer. Thus, my_state generally tells
392 * us not only the last negotiated state, but also tells us what the peer
393 * wants to be doing as well. It is important to understand this difference
394 * as we may wish to be processing data streams based on our desired state
395 * (want_state) or based on what the peer thinks the state is (my_state).
396 *
397 * This all works fine because if the peer sends a positive request, the data
398 * that we receive prior to negative acknowlegment will probably be affected
399 * by the positive state, and we can process it as such (if we can; if we
400 * can't then it really doesn't matter). If it is that important, then the
401 * peer probably should be buffering until this option state negotiation
402 * is complete.
403 *
404 */
405 void
406 send_do(int option, int init)
407 {
408 if (init) {
409 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
410 his_want_state_is_will(option))
411 return;
412 /*
413 * Special case for TELOPT_TM: We send a DO, but pretend
414 * that we sent a DONT, so that we can send more DOs if
415 * we want to.
416 */
417 if (option == TELOPT_TM)
418 set_his_want_state_wont(option);
419 else
420 set_his_want_state_will(option);
421 do_dont_resp[option]++;
422 }
423 output_data((const char *)doopt, option);
424
425 DIAG(TD_OPTIONS, printoption("td: send do", option));
426 }
427
428 void
429 willoption(int option)
430 {
431 int changeok = 0;
432 void (*func)(void) = 0;
433
434 /*
435 * process input from peer.
436 */
437
438 DIAG(TD_OPTIONS, printoption("td: recv will", option));
439
440 if (do_dont_resp[option]) {
441 do_dont_resp[option]--;
442 if (do_dont_resp[option] && his_state_is_will(option))
443 do_dont_resp[option]--;
444 }
445 if (do_dont_resp[option] == 0) {
446 if (his_want_state_is_wont(option)) {
447 switch (option) {
448
449 case TELOPT_BINARY:
450 init_termbuf();
451 tty_binaryin(1);
452 set_termbuf();
453 changeok++;
454 break;
455
456 case TELOPT_ECHO:
457 /*
458 * See comments below for more info.
459 */
460 not42 = 0; /* looks like a 4.2 system */
461 break;
462
463 case TELOPT_TM:
464 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
465 /*
466 * This telnetd implementation does not really
467 * support timing marks, it just uses them to
468 * support the kludge linemode stuff. If we
469 * receive a will or wont TM in response to our
470 * do TM request that may have been sent to
471 * determine kludge linemode support, process
472 * it, otherwise TM should get a negative
473 * response back.
474 */
475 /*
476 * Handle the linemode kludge stuff.
477 * If we are not currently supporting any
478 * linemode at all, then we assume that this
479 * is the client telling us to use kludge
480 * linemode in response to our query. Set the
481 * linemode type that is to be supported, note
482 * that the client wishes to use linemode, and
483 * eat the will TM as though it never arrived.
484 */
485 if (lmodetype < KLUDGE_LINEMODE) {
486 lmodetype = KLUDGE_LINEMODE;
487 clientstat(TELOPT_LINEMODE, WILL, 0);
488 send_wont(TELOPT_SGA, 1);
489 } else if (lmodetype == NO_AUTOKLUDGE) {
490 lmodetype = KLUDGE_OK;
491 }
492 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
493 /*
494 * We never respond to a WILL TM, and
495 * we leave the state WONT.
496 */
497 return;
498
499 case TELOPT_LFLOW:
500 /*
501 * If we are going to support flow control
502 * option, then don't worry peer that we can't
503 * change the flow control characters.
504 */
505 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
506 slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
507 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
508 slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
509 case TELOPT_TTYPE:
510 case TELOPT_SGA:
511 case TELOPT_NAWS:
512 case TELOPT_TSPEED:
513 case TELOPT_XDISPLOC:
514 case TELOPT_NEW_ENVIRON:
515 case TELOPT_OLD_ENVIRON:
516 changeok++;
517 break;
518
519 #ifdef LINEMODE
520 case TELOPT_LINEMODE:
521 # ifdef KLUDGELINEMODE
522 /*
523 * Note client's desire to use linemode.
524 */
525 lmodetype = REAL_LINEMODE;
526 # endif /* KLUDGELINEMODE */
527 func = doclientstat;
528 changeok++;
529 break;
530 #endif /* LINEMODE */
531
532
533
534 default:
535 break;
536 }
537 if (changeok) {
538 set_his_want_state_will(option);
539 send_do(option, 0);
540 } else {
541 do_dont_resp[option]++;
542 send_dont(option, 0);
543 }
544 } else {
545 /*
546 * Option processing that should happen when
547 * we receive conformation of a change in
548 * state that we had requested.
549 */
550 switch (option) {
551 case TELOPT_ECHO:
552 not42 = 0; /* looks like a 4.2 system */
553 /*
554 * Egads, he responded "WILL ECHO". Turn
555 * it off right now!
556 */
557 send_dont(option, 1);
558 /*
559 * "WILL ECHO". Kludge upon kludge!
560 * A 4.2 client is now echoing user input at
561 * the tty. This is probably undesireable and
562 * it should be stopped. The client will
563 * respond WONT TM to the DO TM that we send to
564 * check for kludge linemode. When the WONT TM
565 * arrives, linemode will be turned off and a
566 * change propogated to the pty. This change
567 * will cause us to process the new pty state
568 * in localstat(), which will notice that
569 * linemode is off and send a WILL ECHO
570 * so that we are properly in character mode and
571 * all is well.
572 */
573 break;
574 #ifdef LINEMODE
575 case TELOPT_LINEMODE:
576 # ifdef KLUDGELINEMODE
577 /*
578 * Note client's desire to use linemode.
579 */
580 lmodetype = REAL_LINEMODE;
581 # endif /* KLUDGELINEMODE */
582 func = doclientstat;
583 break;
584 #endif /* LINEMODE */
585
586
587 case TELOPT_LFLOW:
588 func = flowstat;
589 break;
590 }
591 }
592 }
593 set_his_state_will(option);
594 if (func)
595 (*func)();
596 } /* end of willoption */
597
598 void
599 send_dont(int option, int init)
600 {
601 if (init) {
602 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
603 his_want_state_is_wont(option))
604 return;
605 set_his_want_state_wont(option);
606 do_dont_resp[option]++;
607 }
608 output_data((const char *)dont, option);
609
610 DIAG(TD_OPTIONS, printoption("td: send dont", option));
611 }
612
613 void
614 wontoption(int option)
615 {
616 /*
617 * Process client input.
618 */
619
620 DIAG(TD_OPTIONS, printoption("td: recv wont", option));
621
622 if (do_dont_resp[option]) {
623 do_dont_resp[option]--;
624 if (do_dont_resp[option] && his_state_is_wont(option))
625 do_dont_resp[option]--;
626 }
627 if (do_dont_resp[option] == 0) {
628 if (his_want_state_is_will(option)) {
629 /* it is always ok to change to negative state */
630 switch (option) {
631 case TELOPT_ECHO:
632 not42 = 1; /* doesn't seem to be a 4.2 system */
633 break;
634
635 case TELOPT_BINARY:
636 init_termbuf();
637 tty_binaryin(0);
638 set_termbuf();
639 break;
640
641 #ifdef LINEMODE
642 case TELOPT_LINEMODE:
643 # ifdef KLUDGELINEMODE
644 /*
645 * If real linemode is supported, then client is
646 * asking to turn linemode off.
647 */
648 if (lmodetype != REAL_LINEMODE)
649 break;
650 lmodetype = KLUDGE_LINEMODE;
651 # endif /* KLUDGELINEMODE */
652 clientstat(TELOPT_LINEMODE, WONT, 0);
653 break;
654 #endif /* LINEMODE */
655
656 case TELOPT_TM:
657 /*
658 * If we get a WONT TM, and had sent a DO TM,
659 * don't respond with a DONT TM, just leave it
660 * as is. Short circut the state machine to
661 * achive this.
662 */
663 set_his_want_state_wont(TELOPT_TM);
664 return;
665
666 case TELOPT_LFLOW:
667 /*
668 * If we are not going to support flow control
669 * option, then let peer know that we can't
670 * change the flow control characters.
671 */
672 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
673 slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
674 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
675 slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
676 break;
677
678
679 /*
680 * For options that we might spin waiting for
681 * sub-negotiation, if the client turns off the
682 * option rather than responding to the request,
683 * we have to treat it here as if we got a response
684 * to the sub-negotiation, (by updating the timers)
685 * so that we'll break out of the loop.
686 */
687 case TELOPT_TTYPE:
688 settimer(ttypesubopt);
689 break;
690
691 case TELOPT_TSPEED:
692 settimer(tspeedsubopt);
693 break;
694
695 case TELOPT_XDISPLOC:
696 settimer(xdisplocsubopt);
697 break;
698
699 case TELOPT_OLD_ENVIRON:
700 settimer(oenvironsubopt);
701 break;
702
703 case TELOPT_NEW_ENVIRON:
704 settimer(environsubopt);
705 break;
706
707 default:
708 break;
709 }
710 set_his_want_state_wont(option);
711 if (his_state_is_will(option))
712 send_dont(option, 0);
713 } else {
714 switch (option) {
715 case TELOPT_TM:
716 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
717 if (lmodetype < NO_AUTOKLUDGE) {
718 lmodetype = NO_LINEMODE;
719 clientstat(TELOPT_LINEMODE, WONT, 0);
720 send_will(TELOPT_SGA, 1);
721 send_will(TELOPT_ECHO, 1);
722 }
723 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
724 break;
725
726 default:
727 break;
728 }
729 }
730 }
731 set_his_state_wont(option);
732
733 } /* end of wontoption */
734
735 void
736 send_will(int option, int init)
737 {
738 if (init) {
739 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
740 my_want_state_is_will(option))
741 return;
742 set_my_want_state_will(option);
743 will_wont_resp[option]++;
744 }
745 output_data((const char *)will, option);
746
747 DIAG(TD_OPTIONS, printoption("td: send will", option));
748 }
749
750 #if !defined(LINEMODE) || !defined(KLUDGELINEMODE)
751 /*
752 * When we get a DONT SGA, we will try once to turn it
753 * back on. If the other side responds DONT SGA, we
754 * leave it at that. This is so that when we talk to
755 * clients that understand KLUDGELINEMODE but not LINEMODE,
756 * we'll keep them in char-at-a-time mode.
757 */
758 int turn_on_sga = 0;
759 #endif
760
761 void
762 dooption(int option)
763 {
764 int changeok = 0;
765
766 /*
767 * Process client input.
768 */
769
770 DIAG(TD_OPTIONS, printoption("td: recv do", option));
771
772 if (will_wont_resp[option]) {
773 will_wont_resp[option]--;
774 if (will_wont_resp[option] && my_state_is_will(option))
775 will_wont_resp[option]--;
776 }
777 if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
778 switch (option) {
779 case TELOPT_ECHO:
780 #ifdef LINEMODE
781 # ifdef KLUDGELINEMODE
782 if (lmodetype == NO_LINEMODE)
783 # else
784 if (his_state_is_wont(TELOPT_LINEMODE))
785 # endif
786 #endif
787 {
788 init_termbuf();
789 tty_setecho(1);
790 set_termbuf();
791 }
792 changeok++;
793 break;
794
795 case TELOPT_BINARY:
796 init_termbuf();
797 tty_binaryout(1);
798 set_termbuf();
799 changeok++;
800 break;
801
802 case TELOPT_SGA:
803 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
804 /*
805 * If kludge linemode is in use, then we must
806 * process an incoming do SGA for linemode
807 * purposes.
808 */
809 if (lmodetype == KLUDGE_LINEMODE) {
810 /*
811 * Receipt of "do SGA" in kludge
812 * linemode is the peer asking us to
813 * turn off linemode. Make note of
814 * the request.
815 */
816 clientstat(TELOPT_LINEMODE, WONT, 0);
817 /*
818 * If linemode did not get turned off
819 * then don't tell peer that we did.
820 * Breaking here forces a wont SGA to
821 * be returned.
822 */
823 if (linemode)
824 break;
825 }
826 #else
827 turn_on_sga = 0;
828 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
829 changeok++;
830 break;
831
832 case TELOPT_STATUS:
833 changeok++;
834 break;
835
836 case TELOPT_TM:
837 /*
838 * Special case for TM. We send a WILL, but
839 * pretend we sent a WONT.
840 */
841 send_will(option, 0);
842 set_my_want_state_wont(option);
843 set_my_state_wont(option);
844 return;
845
846 case TELOPT_LOGOUT:
847 /*
848 * When we get a LOGOUT option, respond
849 * with a WILL LOGOUT, make sure that
850 * it gets written out to the network,
851 * and then just go away...
852 */
853 set_my_want_state_will(TELOPT_LOGOUT);
854 send_will(TELOPT_LOGOUT, 0);
855 set_my_state_will(TELOPT_LOGOUT);
856 (void)netflush();
857 cleanup(0);
858 /* NOT REACHED */
859 break;
860
861 case TELOPT_LINEMODE:
862 case TELOPT_TTYPE:
863 case TELOPT_NAWS:
864 case TELOPT_TSPEED:
865 case TELOPT_LFLOW:
866 case TELOPT_XDISPLOC:
867 #ifdef TELOPT_ENVIRON
868 case TELOPT_NEW_ENVIRON:
869 #endif
870 case TELOPT_OLD_ENVIRON:
871 default:
872 break;
873 }
874 if (changeok) {
875 set_my_want_state_will(option);
876 send_will(option, 0);
877 } else {
878 will_wont_resp[option]++;
879 send_wont(option, 0);
880 }
881 }
882 set_my_state_will(option);
883
884 } /* end of dooption */
885
886 void
887 send_wont(int option, int init)
888 {
889 if (init) {
890 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
891 my_want_state_is_wont(option))
892 return;
893 set_my_want_state_wont(option);
894 will_wont_resp[option]++;
895 }
896 output_data((const char *)wont, option);
897
898 DIAG(TD_OPTIONS, printoption("td: send wont", option));
899 }
900
901 void
902 dontoption(int option)
903 {
904 /*
905 * Process client input.
906 */
907
908
909 DIAG(TD_OPTIONS, printoption("td: recv dont", option));
910
911 if (will_wont_resp[option]) {
912 will_wont_resp[option]--;
913 if (will_wont_resp[option] && my_state_is_wont(option))
914 will_wont_resp[option]--;
915 }
916 if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
917 switch (option) {
918 case TELOPT_BINARY:
919 init_termbuf();
920 tty_binaryout(0);
921 set_termbuf();
922 break;
923
924 case TELOPT_ECHO: /* we should stop echoing */
925 #ifdef LINEMODE
926 # ifdef KLUDGELINEMODE
927 if ((lmodetype != REAL_LINEMODE) &&
928 (lmodetype != KLUDGE_LINEMODE))
929 # else
930 if (his_state_is_wont(TELOPT_LINEMODE))
931 # endif
932 #endif
933 {
934 init_termbuf();
935 tty_setecho(0);
936 set_termbuf();
937 }
938 break;
939
940 case TELOPT_SGA:
941 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
942 /*
943 * If kludge linemode is in use, then we
944 * must process an incoming do SGA for
945 * linemode purposes.
946 */
947 if ((lmodetype == KLUDGE_LINEMODE) ||
948 (lmodetype == KLUDGE_OK)) {
949 /*
950 * The client is asking us to turn
951 * linemode on.
952 */
953 lmodetype = KLUDGE_LINEMODE;
954 clientstat(TELOPT_LINEMODE, WILL, 0);
955 /*
956 * If we did not turn line mode on,
957 * then what do we say? Will SGA?
958 * This violates design of telnet.
959 * Gross. Very Gross.
960 */
961 }
962 break;
963 #else
964 set_my_want_state_wont(option);
965 if (my_state_is_will(option))
966 send_wont(option, 0);
967 set_my_state_wont(option);
968 if (turn_on_sga ^= 1)
969 send_will(option, 1);
970 return;
971 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
972
973 default:
974 break;
975 }
976
977 set_my_want_state_wont(option);
978 if (my_state_is_will(option))
979 send_wont(option, 0);
980 }
981 set_my_state_wont(option);
982
983 } /* end of dontoption */
984
985 #ifdef ENV_HACK
986 int env_ovar = -1;
987 int env_ovalue = -1;
988 #else /* ENV_HACK */
989 # define env_ovar OLD_ENV_VAR
990 # define env_ovalue OLD_ENV_VALUE
991 #endif /* ENV_HACK */
992
993 /*
994 * suboption()
995 *
996 * Look at the sub-option buffer, and try to be helpful to the other
997 * side.
998 *
999 * Currently we recognize:
1000 *
1001 * Terminal type is
1002 * Linemode
1003 * Window size
1004 * Terminal speed
1005 */
1006 void
1007 suboption(void)
1008 {
1009 int subchar;
1010
1011 DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1012
1013 subchar = SB_GET();
1014 switch (subchar) {
1015 case TELOPT_TSPEED: {
1016 int xspeed, rspeed;
1017
1018 if (his_state_is_wont(TELOPT_TSPEED)) /* Ignore if option disabled */
1019 break;
1020
1021 settimer(tspeedsubopt);
1022
1023 if (SB_EOF() || SB_GET() != TELQUAL_IS)
1024 return;
1025
1026 xspeed = atoi((char *)subpointer);
1027
1028 while (SB_GET() != ',' && !SB_EOF());
1029 if (SB_EOF())
1030 return;
1031
1032 rspeed = atoi((char *)subpointer);
1033 clientstat(TELOPT_TSPEED, xspeed, rspeed);
1034
1035 break;
1036
1037 } /* end of case TELOPT_TSPEED */
1038
1039 case TELOPT_TTYPE: { /* Yaaaay! */
1040 static char terminalname[41];
1041
1042 if (his_state_is_wont(TELOPT_TTYPE)) /* Ignore if option disabled */
1043 break;
1044 settimer(ttypesubopt);
1045
1046 if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1047 return; /* ??? XXX but, this is the most robust */
1048 }
1049
1050 terminaltype = terminalname;
1051
1052 while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1053 !SB_EOF()) {
1054 int c;
1055
1056 c = SB_GET();
1057 if (isupper(c)) {
1058 c = tolower(c);
1059 }
1060 *terminaltype++ = c; /* accumulate name */
1061 }
1062 *terminaltype = 0;
1063 terminaltype = terminalname;
1064 break;
1065 } /* end of case TELOPT_TTYPE */
1066
1067 case TELOPT_NAWS: {
1068 int xwinsize, ywinsize;
1069
1070 if (his_state_is_wont(TELOPT_NAWS)) /* Ignore if option disabled */
1071 break;
1072
1073 if (SB_EOF())
1074 return;
1075 xwinsize = SB_GET() << 8;
1076 if (SB_EOF())
1077 return;
1078 xwinsize |= SB_GET();
1079 if (SB_EOF())
1080 return;
1081 ywinsize = SB_GET() << 8;
1082 if (SB_EOF())
1083 return;
1084 ywinsize |= SB_GET();
1085 clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1086
1087 break;
1088
1089 } /* end of case TELOPT_NAWS */
1090
1091 #ifdef LINEMODE
1092 case TELOPT_LINEMODE: {
1093 int request;
1094
1095 if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1096 break;
1097 /*
1098 * Process linemode suboptions.
1099 */
1100 if (SB_EOF())
1101 break; /* garbage was sent */
1102 request = SB_GET(); /* get will/wont */
1103
1104 if (SB_EOF())
1105 break; /* another garbage check */
1106
1107 if (request == LM_SLC) { /* SLC is not preceeded by WILL or WONT */
1108 /*
1109 * Process suboption buffer of slc's
1110 */
1111 start_slc(1);
1112 do_opt_slc(subpointer, subend - subpointer);
1113 (void) end_slc(0);
1114 break;
1115 } else if (request == LM_MODE) {
1116 if (SB_EOF())
1117 return;
1118 useeditmode = SB_GET(); /* get mode flag */
1119 clientstat(LM_MODE, 0, 0);
1120 break;
1121 }
1122
1123 if (SB_EOF())
1124 break;
1125 switch (SB_GET()) { /* what suboption? */
1126 case LM_FORWARDMASK:
1127 /*
1128 * According to spec, only server can send request for
1129 * forwardmask, and client can only return a positive response.
1130 * So don't worry about it.
1131 */
1132
1133 default:
1134 break;
1135 }
1136 break;
1137 } /* end of case TELOPT_LINEMODE */
1138 #endif
1139 case TELOPT_STATUS: {
1140 int mode;
1141
1142 if (SB_EOF())
1143 break;
1144 mode = SB_GET();
1145 switch (mode) {
1146 case TELQUAL_SEND:
1147 if (my_state_is_will(TELOPT_STATUS))
1148 send_status();
1149 break;
1150
1151 case TELQUAL_IS:
1152 break;
1153
1154 default:
1155 break;
1156 }
1157 break;
1158 } /* end of case TELOPT_STATUS */
1159
1160 case TELOPT_XDISPLOC: {
1161 if (SB_EOF() || SB_GET() != TELQUAL_IS)
1162 return;
1163 settimer(xdisplocsubopt);
1164 subpointer[SB_LEN()] = '\0';
1165 if (setenv("DISPLAY", (char *)subpointer, 1) == -1)
1166 syslog(LOG_ERR, "setenv: cannot set DISPLAY=%s: %m", (char *)subpointer);
1167 break;
1168 } /* end of case TELOPT_XDISPLOC */
1169
1170 #ifdef TELOPT_NEW_ENVIRON
1171 case TELOPT_NEW_ENVIRON:
1172 #endif
1173 case TELOPT_OLD_ENVIRON: {
1174 int c;
1175 char *cp, *varp, *valp;
1176
1177 if (SB_EOF())
1178 return;
1179 c = SB_GET();
1180 if (c == TELQUAL_IS) {
1181 if (subchar == TELOPT_OLD_ENVIRON)
1182 settimer(oenvironsubopt);
1183 else
1184 settimer(environsubopt);
1185 } else if (c != TELQUAL_INFO) {
1186 return;
1187 }
1188
1189 #ifdef TELOPT_NEW_ENVIRON
1190 if (subchar == TELOPT_NEW_ENVIRON) {
1191 while (!SB_EOF()) {
1192 c = SB_GET();
1193 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1194 break;
1195 }
1196 } else
1197 #endif
1198 {
1199 #ifdef ENV_HACK
1200 /*
1201 * We only want to do this if we haven't already decided
1202 * whether or not the other side has its VALUE and VAR
1203 * reversed.
1204 */
1205 if (env_ovar < 0) {
1206 int last = -1; /* invalid value */
1207 int empty = 0;
1208 int got_var = 0, got_value = 0, got_uservar = 0;
1209
1210 /*
1211 * The other side might have its VALUE and VAR values
1212 * reversed. To be interoperable, we need to determine
1213 * which way it is. If the first recognized character
1214 * is a VAR or VALUE, then that will tell us what
1215 * type of client it is. If the fist recognized
1216 * character is a USERVAR, then we continue scanning
1217 * the suboption looking for two consecutive
1218 * VAR or VALUE fields. We should not get two
1219 * consecutive VALUE fields, so finding two
1220 * consecutive VALUE or VAR fields will tell us
1221 * what the client is.
1222 */
1223 SB_SAVE();
1224 while (!SB_EOF()) {
1225 c = SB_GET();
1226 switch(c) {
1227 case OLD_ENV_VAR:
1228 if (last < 0 || last == OLD_ENV_VAR
1229 || (empty && (last == OLD_ENV_VALUE)))
1230 goto env_ovar_ok;
1231 got_var++;
1232 last = OLD_ENV_VAR;
1233 break;
1234 case OLD_ENV_VALUE:
1235 if (last < 0 || last == OLD_ENV_VALUE
1236 || (empty && (last == OLD_ENV_VAR)))
1237 goto env_ovar_wrong;
1238 got_value++;
1239 last = OLD_ENV_VALUE;
1240 break;
1241 case ENV_USERVAR:
1242 /* count strings of USERVAR as one */
1243 if (last != ENV_USERVAR)
1244 got_uservar++;
1245 if (empty) {
1246 if (last == OLD_ENV_VALUE)
1247 goto env_ovar_ok;
1248 if (last == OLD_ENV_VAR)
1249 goto env_ovar_wrong;
1250 }
1251 last = ENV_USERVAR;
1252 break;
1253 case ENV_ESC:
1254 if (!SB_EOF())
1255 c = SB_GET();
1256 /* FALL THROUGH */
1257 default:
1258 empty = 0;
1259 continue;
1260 }
1261 empty = 1;
1262 }
1263 if (empty) {
1264 if (last == OLD_ENV_VALUE)
1265 goto env_ovar_ok;
1266 if (last == OLD_ENV_VAR)
1267 goto env_ovar_wrong;
1268 }
1269 /*
1270 * Ok, the first thing was a USERVAR, and there
1271 * are not two consecutive VAR or VALUE commands,
1272 * and none of the VAR or VALUE commands are empty.
1273 * If the client has sent us a well-formed option,
1274 * then the number of VALUEs received should always
1275 * be less than or equal to the number of VARs and
1276 * USERVARs received.
1277 *
1278 * If we got exactly as many VALUEs as VARs and
1279 * USERVARs, the client has the same definitions.
1280 *
1281 * If we got exactly as many VARs as VALUEs and
1282 * USERVARS, the client has reversed definitions.
1283 */
1284 if (got_uservar + got_var == got_value) {
1285 env_ovar_ok:
1286 env_ovar = OLD_ENV_VAR;
1287 env_ovalue = OLD_ENV_VALUE;
1288 } else if (got_uservar + got_value == got_var) {
1289 env_ovar_wrong:
1290 env_ovar = OLD_ENV_VALUE;
1291 env_ovalue = OLD_ENV_VAR;
1292 DIAG(TD_OPTIONS,
1293 output_data("ENVIRON VALUE and VAR are reversed!\r\n"));
1294
1295 }
1296 }
1297 SB_RESTORE();
1298 #endif
1299
1300 while (!SB_EOF()) {
1301 c = SB_GET();
1302 if ((c == env_ovar) || (c == ENV_USERVAR))
1303 break;
1304 }
1305 }
1306
1307 if (SB_EOF())
1308 return;
1309
1310 cp = varp = (char *)subpointer;
1311 valp = 0;
1312
1313 while (!SB_EOF()) {
1314 c = SB_GET();
1315 if (subchar == TELOPT_OLD_ENVIRON) {
1316 if (c == env_ovar)
1317 c = NEW_ENV_VAR;
1318 else if (c == env_ovalue)
1319 c = NEW_ENV_VALUE;
1320 }
1321 switch (c) {
1322
1323 case NEW_ENV_VALUE:
1324 *cp = '\0';
1325 cp = valp = (char *)subpointer;
1326 break;
1327
1328 case NEW_ENV_VAR:
1329 case ENV_USERVAR:
1330 *cp = '\0';
1331 if (valp) {
1332 if (setenv(varp, valp, 1) == -1)
1333 syslog(LOG_ERR, "setenv: cannot set %s=%s: %m", varp, valp);
1334 }
1335 else
1336 unsetenv(varp);
1337 cp = varp = (char *)subpointer;
1338 valp = 0;
1339 break;
1340
1341 case ENV_ESC:
1342 if (SB_EOF())
1343 break;
1344 c = SB_GET();
1345 /* FALL THROUGH */
1346 default:
1347 *cp++ = c;
1348 break;
1349 }
1350 }
1351 *cp = '\0';
1352 if (valp) {
1353 if (setenv(varp, valp, 1) == -1)
1354 syslog(LOG_ERR, "setenv: cannot set %s=%s: %m", varp, valp);
1355 }
1356 else
1357 unsetenv(varp);
1358 break;
1359 } /* end of case TELOPT_NEW_ENVIRON */
1360
1361 default:
1362 break;
1363 } /* end of switch */
1364
1365 } /* end of suboption */
1366
1367 static void
1368 doclientstat(void)
1369 {
1370 clientstat(TELOPT_LINEMODE, WILL, 0);
1371 }
1372
1373 #define ADD(c) *ncp++ = c
1374 #define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1375 void
1376 send_status(void)
1377 {
1378 unsigned char statusbuf[256];
1379 unsigned char *ncp;
1380 unsigned char i;
1381
1382 ncp = statusbuf;
1383
1384 netflush(); /* get rid of anything waiting to go out */
1385
1386 ADD(IAC);
1387 ADD(SB);
1388 ADD(TELOPT_STATUS);
1389 ADD(TELQUAL_IS);
1390
1391 /*
1392 * We check the want_state rather than the current state,
1393 * because if we received a DO/WILL for an option that we
1394 * don't support, and the other side didn't send a DONT/WONT
1395 * in response to our WONT/DONT, then the "state" will be
1396 * WILL/DO, and the "want_state" will be WONT/DONT. We
1397 * need to go by the latter.
1398 */
1399 for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1400 if (my_want_state_is_will(i)) {
1401 ADD(WILL);
1402 ADD_DATA(i);
1403 if (i == IAC)
1404 ADD(IAC);
1405 }
1406 if (his_want_state_is_will(i)) {
1407 ADD(DO);
1408 ADD_DATA(i);
1409 if (i == IAC)
1410 ADD(IAC);
1411 }
1412 }
1413
1414 if (his_want_state_is_will(TELOPT_LFLOW)) {
1415 ADD(SB);
1416 ADD(TELOPT_LFLOW);
1417 if (flowmode) {
1418 ADD(LFLOW_ON);
1419 } else {
1420 ADD(LFLOW_OFF);
1421 }
1422 ADD(SE);
1423
1424 if (restartany >= 0) {
1425 ADD(SB);
1426 ADD(TELOPT_LFLOW);
1427 if (restartany) {
1428 ADD(LFLOW_RESTART_ANY);
1429 } else {
1430 ADD(LFLOW_RESTART_XON);
1431 }
1432 ADD(SE);
1433 }
1434 }
1435
1436 #ifdef LINEMODE
1437 if (his_want_state_is_will(TELOPT_LINEMODE)) {
1438 unsigned char *cp, *cpe;
1439 int len;
1440
1441 ADD(SB);
1442 ADD(TELOPT_LINEMODE);
1443 ADD(LM_MODE);
1444 ADD_DATA(editmode);
1445 ADD(SE);
1446
1447 ADD(SB);
1448 ADD(TELOPT_LINEMODE);
1449 ADD(LM_SLC);
1450 start_slc(0);
1451 send_slc();
1452 len = end_slc(&cp);
1453 for (cpe = cp + len; cp < cpe; cp++)
1454 ADD_DATA(*cp);
1455 ADD(SE);
1456 }
1457 #endif /* LINEMODE */
1458
1459 ADD(IAC);
1460 ADD(SE);
1461
1462 output_datalen(statusbuf, ncp - statusbuf);
1463 netflush(); /* Send it on its way */
1464
1465 DIAG(TD_OPTIONS,
1466 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1467 }
1468
1469 /*
1470 * This function appends data to nfrontp and advances nfrontp.
1471 * Returns the number of characters written altogether (the
1472 * buffer may have been flushed in the process).
1473 */
1474
1475 int
1476 output_data(const char *format, ...)
1477 {
1478 va_list args;
1479 int len;
1480 char *buf;
1481
1482 va_start(args, format);
1483 if ((len = vasprintf(&buf, format, args)) == -1)
1484 return -1;
1485 output_datalen(buf, len);
1486 va_end(args);
1487 free(buf);
1488 return (len);
1489 }
1490
1491 void
1492 output_datalen(const char *buf, int len)
1493 {
1494 int remaining, copied;
1495
1496 remaining = BUFSIZ - (nfrontp - netobuf);
1497 while (len > 0) {
1498 /* Free up enough space if the room is too low*/
1499 if ((len > BUFSIZ ? BUFSIZ : len) > remaining) {
1500 netflush();
1501 remaining = BUFSIZ - (nfrontp - netobuf);
1502 }
1503
1504 /* Copy out as much as will fit */
1505 copied = remaining > len ? len : remaining;
1506 memmove(nfrontp, buf, copied);
1507 nfrontp += copied;
1508 len -= copied;
1509 remaining -= copied;
1510 buf += copied;
1511 }
1512 return;
1513 }
DragonFly BSD