1 /* $NetBSD: state.c,v 1.35 2024/10/29 13:10:10 kre Exp $ */
2
3 /*
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)state.c 8.5 (Berkeley) 5/30/95";
36 #else
37 __RCSID("$NetBSD: state.c,v 1.35 2024/10/29 13:10:10 kre Exp $");
38 #endif
39 #endif /* not lint */
40
41 #include <ctype.h>
42 #include <stdarg.h>
43
44 #include "telnetd.h"
45
46 static int envvarok(char *);
47
48 int not42 = 1;
49
50 /*
51 * Buffer for sub-options, and macros
52 * for suboptions buffer manipulations
53 */
54 unsigned char subbuffer[4096], *subpointer= subbuffer, *subend= subbuffer;
55
56 #define SB_CLEAR() subpointer = subbuffer
57 #define SB_TERM() { subend = subpointer; SB_CLEAR(); }
58 #define SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { \
59 *subpointer++ = (c); \
60 }
61 #define SB_GET() ((*subpointer++)&0xff)
62 #define SB_EOF() (subpointer >= subend)
63 #define SB_LEN() (subend - subpointer)
64
65 #ifdef ENV_HACK
66 unsigned char *subsave;
67 #define SB_SAVE() subsave = subpointer;
68 #define SB_RESTORE() subpointer = subsave;
69 #endif
70
71
72 /*
73 * State for recv fsm
74 */
75 #define TS_DATA 0 /* base state */
76 #define TS_IAC 1 /* look for double IAC's */
77 #define TS_CR 2 /* CR-LF ->'s CR */
78 #define TS_SB 3 /* throw away begin's... */
79 #define TS_SE 4 /* ...end's (suboption negotiation) */
80 #define TS_WILL 5 /* will option negotiation */
81 #define TS_WONT 6 /* wont " */
82 #define TS_DO 7 /* do " */
83 #define TS_DONT 8 /* dont " */
84
85 void
telrcv(void)86 telrcv(void)
87 {
88 int c;
89 static int state = TS_DATA;
90
91 while (ncc > 0) {
92 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
93 break;
94 c = *netip++ & 0377, ncc--;
95 #ifdef ENCRYPTION
96 if (decrypt_input)
97 c = (*decrypt_input)(c);
98 #endif /* ENCRYPTION */
99 switch (state) {
100
101 case TS_CR:
102 state = TS_DATA;
103
104 #ifdef LINEMODE
105 /*
106 * If we are operating in linemode,
107 * convert to local end-of-line.
108 */
109 if (linemode && (ncc > 0) && ((c == '\n') ||
110 ((c == 0) && tty_iscrnl())) )
111 c = '\n';
112 else
113 #endif
114 {
115 /*
116 * We now map \r\n ==> \r for pragmatic reasons.
117 * Many client implementations send \r\n when
118 * the user hits the CarriageReturn key.
119 *
120 * We USED to map \r\n ==> \n, since \r\n says
121 * that we want to be in column 1 of the next
122 * printable line, and \n is the standard
123 * unix way of saying that (\r is only good
124 * if CRMOD is set, which it normally is).
125 */
126
127 /* Strip off \n or \0 after a \r */
128 if ((c == 0) || (c == '\n'))
129 break;
130 }
131 /* FALL THROUGH */
132
133 case TS_DATA:
134 if (c == IAC) {
135 state = TS_IAC;
136 break;
137 }
138
139 if ((c == '\r') && his_state_is_wont(TELOPT_BINARY))
140 state = TS_CR;
141
142 *pfrontp++ = c;
143 break;
144
145 case TS_IAC:
146 gotiac: switch (c) {
147
148 /*
149 * Send the process on the pty side an
150 * interrupt. Do this with a NULL or
151 * interrupt char; depending on the tty mode.
152 */
153 case IP:
154 DIAG(TD_OPTIONS,
155 printoption("td: recv IAC", c));
156 interrupt();
157 break;
158
159 case BREAK:
160 DIAG(TD_OPTIONS,
161 printoption("td: recv IAC", c));
162 sendbrk();
163 break;
164
165 /*
166 * Are You There?
167 */
168 case AYT:
169 DIAG(TD_OPTIONS,
170 printoption("td: recv IAC", c));
171 recv_ayt();
172 break;
173
174 /*
175 * Abort Output
176 */
177 case AO:
178 {
179 DIAG(TD_OPTIONS,
180 printoption("td: recv IAC", c));
181 ptyflush(); /* half-hearted */
182 init_termbuf();
183
184 if (slctab[SLC_AO].sptr &&
185 *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
186 *pfrontp++ =
187 (unsigned char)*slctab[SLC_AO].sptr;
188 }
189
190 netclear(); /* clear buffer back */
191 output_data("%c%c", IAC, DM);
192 neturg = nfrontp - 1; /* off by one XXX */
193 DIAG(TD_OPTIONS,
194 printoption("td: send IAC", DM));
195 break;
196 }
197
198 /*
199 * Erase Character and
200 * Erase Line
201 */
202 case EC:
203 case EL:
204 {
205 cc_t ch;
206
207 DIAG(TD_OPTIONS,
208 printoption("td: recv IAC", c));
209 ptyflush(); /* half-hearted */
210 init_termbuf();
211 if (c == EC)
212 ch = *slctab[SLC_EC].sptr;
213 else
214 ch = *slctab[SLC_EL].sptr;
215 if (ch != (cc_t)(_POSIX_VDISABLE))
216 *pfrontp++ = (unsigned char)ch;
217 break;
218 }
219
220 /*
221 * Check for urgent data...
222 */
223 case DM:
224 DIAG(TD_OPTIONS,
225 printoption("td: recv IAC", c));
226 SYNCHing = stilloob(net);
227 settimer(gotDM);
228 break;
229
230
231 /*
232 * Begin option subnegotiation...
233 */
234 case SB:
235 state = TS_SB;
236 SB_CLEAR();
237 continue;
238
239 case WILL:
240 state = TS_WILL;
241 continue;
242
243 case WONT:
244 state = TS_WONT;
245 continue;
246
247 case DO:
248 state = TS_DO;
249 continue;
250
251 case DONT:
252 state = TS_DONT;
253 continue;
254 case EOR:
255 if (his_state_is_will(TELOPT_EOR))
256 doeof();
257 break;
258
259 /*
260 * Handle RFC 10xx Telnet linemode option additions
261 * to command stream (EOF, SUSP, ABORT).
262 */
263 case xEOF:
264 doeof();
265 break;
266
267 case SUSP:
268 sendsusp();
269 break;
270
271 case ABORT:
272 sendbrk();
273 break;
274
275 case IAC:
276 *pfrontp++ = c;
277 break;
278 }
279 state = TS_DATA;
280 break;
281
282 case TS_SB:
283 if (c == IAC) {
284 state = TS_SE;
285 } else {
286 SB_ACCUM(c);
287 }
288 break;
289
290 case TS_SE:
291 if (c != SE) {
292 if (c != IAC) {
293 /*
294 * bad form of suboption negotiation.
295 * handle it in such a way as to avoid
296 * damage to local state. Parse
297 * suboption buffer found so far,
298 * then treat remaining stream as
299 * another command sequence.
300 */
301
302 /* for DIAGNOSTICS */
303 SB_ACCUM(IAC);
304 SB_ACCUM(c);
305 subpointer -= 2;
306
307 SB_TERM();
308 suboption();
309 state = TS_IAC;
310 goto gotiac;
311 }
312 SB_ACCUM(c);
313 state = TS_SB;
314 } else {
315 /* for DIAGNOSTICS */
316 SB_ACCUM(IAC);
317 SB_ACCUM(SE);
318 subpointer -= 2;
319
320 SB_TERM();
321 suboption(); /* handle sub-option */
322 state = TS_DATA;
323 }
324 break;
325
326 case TS_WILL:
327 willoption(c);
328 state = TS_DATA;
329 continue;
330
331 case TS_WONT:
332 wontoption(c);
333 state = TS_DATA;
334 continue;
335
336 case TS_DO:
337 dooption(c);
338 state = TS_DATA;
339 continue;
340
341 case TS_DONT:
342 dontoption(c);
343 state = TS_DATA;
344 continue;
345
346 default:
347 syslog(LOG_ERR, "panic state=%d", state);
348 printf("telnetd: panic state=%d\n", state);
349 exit(1);
350 }
351 }
352 } /* end of telrcv */
353
354 /*
355 * The will/wont/do/dont state machines are based on Dave Borman's
356 * Telnet option processing state machine.
357 *
358 * These correspond to the following states:
359 * my_state = the last negotiated state
360 * want_state = what I want the state to go to
361 * want_resp = how many requests I have sent
362 * All state defaults are negative, and resp defaults to 0.
363 *
364 * When initiating a request to change state to new_state:
365 *
366 * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
367 * do nothing;
368 * } else {
369 * want_state = new_state;
370 * send new_state;
371 * want_resp++;
372 * }
373 *
374 * When receiving new_state:
375 *
376 * if (want_resp) {
377 * want_resp--;
378 * if (want_resp && (new_state == my_state))
379 * want_resp--;
380 * }
381 * if ((want_resp == 0) && (new_state != want_state)) {
382 * if (ok_to_switch_to new_state)
383 * want_state = new_state;
384 * else
385 * want_resp++;
386 * send want_state;
387 * }
388 * my_state = new_state;
389 *
390 * Note that new_state is implied in these functions by the function itself.
391 * will and do imply positive new_state, wont and dont imply negative.
392 *
393 * Finally, there is one catch. If we send a negative response to a
394 * positive request, my_state will be the positive while want_state will
395 * remain negative. my_state will revert to negative when the negative
396 * acknowledgment arrives from the peer. Thus, my_state generally tells
397 * us not only the last negotiated state, but also tells us what the peer
398 * wants to be doing as well. It is important to understand this difference
399 * as we may wish to be processing data streams based on our desired state
400 * (want_state) or based on what the peer thinks the state is (my_state).
401 *
402 * This all works fine because if the peer sends a positive request, the data
403 * that we receive prior to negative acknowledgment will probably be affected
404 * by the positive state, and we can process it as such (if we can; if we
405 * can't then it really doesn't matter). If it is that important, then the
406 * peer probably should be buffering until this option state negotiation
407 * is complete.
408 *
409 */
410 void
send_do(int option,int init)411 send_do(int option, int init)
412 {
413 if (init) {
414 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
415 his_want_state_is_will(option))
416 return;
417 /*
418 * Special case for TELOPT_TM: We send a DO, but pretend
419 * that we sent a DONT, so that we can send more DOs if
420 * we want to.
421 */
422 if (option == TELOPT_TM)
423 set_his_want_state_wont(option);
424 else
425 set_his_want_state_will(option);
426 do_dont_resp[option]++;
427 }
428 (void) output_data("%c%c%c", IAC, DO, option);
429
430 DIAG(TD_OPTIONS, printoption("td: send do", option));
431 }
432
433 #ifdef LINEMODE
434 extern void doclientstat(void);
435 #endif
436 #if 0
437 #ifdef AUTHENTICATION
438 extern void auth_request(void); /* libtelnet */
439 #endif
440 #ifdef ENCRYPTION
441 extern void encrypt_send_support(void);
442 #endif /* ENCRYPTION */
443 #endif
444
445 void
willoption(int option)446 willoption(int option)
447 {
448 int changeok = 0;
449 void (*func)(void) = 0;
450
451 /*
452 * process input from peer.
453 */
454
455 DIAG(TD_OPTIONS, printoption("td: recv will", option));
456
457 if (do_dont_resp[option]) {
458 do_dont_resp[option]--;
459 if (do_dont_resp[option] && his_state_is_will(option))
460 do_dont_resp[option]--;
461 }
462 if (do_dont_resp[option] == 0) {
463 if (his_want_state_is_wont(option)) {
464 switch (option) {
465
466 case TELOPT_BINARY:
467 init_termbuf();
468 tty_binaryin(1);
469 set_termbuf();
470 changeok++;
471 break;
472
473 case TELOPT_ECHO:
474 /*
475 * See comments below for more info.
476 */
477 not42 = 0; /* looks like a 4.2 system */
478 break;
479
480 case TELOPT_TM:
481 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
482 /*
483 * This telnetd implementation does not really
484 * support timing marks, it just uses them to
485 * support the kludge linemode stuff. If we
486 * receive a will or wont TM in response to our
487 * do TM request that may have been sent to
488 * determine kludge linemode support, process
489 * it, otherwise TM should get a negative
490 * response back.
491 */
492 /*
493 * Handle the linemode kludge stuff.
494 * If we are not currently supporting any
495 * linemode at all, then we assume that this
496 * is the client telling us to use kludge
497 * linemode in response to our query. Set the
498 * linemode type that is to be supported, note
499 * that the client wishes to use linemode, and
500 * eat the will TM as though it never arrived.
501 */
502 if (lmodetype < KLUDGE_LINEMODE) {
503 lmodetype = KLUDGE_LINEMODE;
504 clientstat(TELOPT_LINEMODE, WILL, 0);
505 send_wont(TELOPT_SGA, 1);
506 } else if (lmodetype == NO_AUTOKLUDGE) {
507 lmodetype = KLUDGE_OK;
508 }
509 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
510 /*
511 * We never respond to a WILL TM, and
512 * we leave the state WONT.
513 */
514 return;
515
516 case TELOPT_LFLOW:
517 /*
518 * If we are going to support flow control
519 * option, then don't worry peer that we can't
520 * change the flow control characters.
521 */
522 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
523 slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
524 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
525 slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
526 /* FALLTHROUGH */
527 case TELOPT_TTYPE:
528 case TELOPT_SGA:
529 case TELOPT_NAWS:
530 case TELOPT_TSPEED:
531 case TELOPT_XDISPLOC:
532 case TELOPT_NEW_ENVIRON:
533 case TELOPT_OLD_ENVIRON:
534 changeok++;
535 break;
536
537 #ifdef LINEMODE
538 case TELOPT_LINEMODE:
539 # ifdef KLUDGELINEMODE
540 /*
541 * Note client's desire to use linemode.
542 */
543 lmodetype = REAL_LINEMODE;
544 # endif /* KLUDGELINEMODE */
545 func = doclientstat;
546 changeok++;
547 break;
548 #endif /* LINEMODE */
549
550 #ifdef AUTHENTICATION
551 case TELOPT_AUTHENTICATION:
552 if (auth_level >= 0) {
553 func = auth_request;
554 changeok++;
555 }
556 break;
557 #endif
558
559 #ifdef ENCRYPTION
560 case TELOPT_ENCRYPT:
561 func = encrypt_send_support;
562 changeok++;
563 break;
564 #endif /* ENCRYPTION */
565
566 default:
567 break;
568 }
569 if (changeok) {
570 set_his_want_state_will(option);
571 send_do(option, 0);
572 } else {
573 do_dont_resp[option]++;
574 send_dont(option, 0);
575 }
576 } else {
577 /*
578 * Option processing that should happen when
579 * we receive conformation of a change in
580 * state that we had requested.
581 */
582 switch (option) {
583 case TELOPT_ECHO:
584 not42 = 0; /* looks like a 4.2 system */
585 /*
586 * Egads, he responded "WILL ECHO". Turn
587 * it off right now!
588 */
589 send_dont(option, 1);
590 /*
591 * "WILL ECHO". Kludge upon kludge!
592 * A 4.2 client is now echoing user input at
593 * the tty. This is probably undesireable and
594 * it should be stopped. The client will
595 * respond WONT TM to the DO TM that we send to
596 * check for kludge linemode. When the WONT TM
597 * arrives, linemode will be turned off and a
598 * change propagated to the pty. This change
599 * will cause us to process the new pty state
600 * in localstat(), which will notice that
601 * linemode is off and send a WILL ECHO
602 * so that we are properly in character mode and
603 * all is well.
604 */
605 break;
606 #ifdef LINEMODE
607 case TELOPT_LINEMODE:
608 # ifdef KLUDGELINEMODE
609 /*
610 * Note client's desire to use linemode.
611 */
612 lmodetype = REAL_LINEMODE;
613 # endif /* KLUDGELINEMODE */
614 func = doclientstat;
615 break;
616 #endif /* LINEMODE */
617
618 #ifdef AUTHENTICATION
619 case TELOPT_AUTHENTICATION:
620 func = auth_request;
621 break;
622 #endif
623
624 #ifdef ENCRYPTION
625 case TELOPT_ENCRYPT:
626 func = encrypt_send_support;
627 break;
628 #endif /* ENCRYPTION */
629
630 case TELOPT_LFLOW:
631 func = flowstat;
632 break;
633 }
634 }
635 }
636 set_his_state_will(option);
637 if (func)
638 (*func)();
639 } /* end of willoption */
640
641 void
send_dont(int option,int init)642 send_dont(int option, int init)
643 {
644 if (init) {
645 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
646 his_want_state_is_wont(option))
647 return;
648 set_his_want_state_wont(option);
649 do_dont_resp[option]++;
650 }
651 (void) output_data("%c%c%c", IAC, DONT, option);
652
653 DIAG(TD_OPTIONS, printoption("td: send dont", option));
654 }
655
656 void
wontoption(int option)657 wontoption(int option)
658 {
659 /*
660 * Process client input.
661 */
662
663 DIAG(TD_OPTIONS, printoption("td: recv wont", option));
664
665 if (do_dont_resp[option]) {
666 do_dont_resp[option]--;
667 if (do_dont_resp[option] && his_state_is_wont(option))
668 do_dont_resp[option]--;
669 }
670 if (do_dont_resp[option] == 0) {
671 if (his_want_state_is_will(option)) {
672 /* it is always ok to change to negative state */
673 switch (option) {
674 case TELOPT_ECHO:
675 not42 = 1; /* doesn't seem to be a 4.2 system */
676 break;
677
678 case TELOPT_BINARY:
679 init_termbuf();
680 tty_binaryin(0);
681 set_termbuf();
682 break;
683
684 #ifdef LINEMODE
685 case TELOPT_LINEMODE:
686 # ifdef KLUDGELINEMODE
687 /*
688 * If real linemode is supported, then client is
689 * asking to turn linemode off.
690 */
691 if (lmodetype != REAL_LINEMODE)
692 break;
693 /* XXX double-check this --thorpej */
694 lmodetype = KLUDGE_LINEMODE;
695 # endif /* KLUDGELINEMODE */
696 clientstat(TELOPT_LINEMODE, WONT, 0);
697 break;
698 #endif /* LINEMODE */
699
700 case TELOPT_TM:
701 /*
702 * If we get a WONT TM, and had sent a DO TM,
703 * don't respond with a DONT TM, just leave it
704 * as is. Short circut the state machine to
705 * achieve this.
706 */
707 set_his_want_state_wont(TELOPT_TM);
708 return;
709
710 case TELOPT_LFLOW:
711 /*
712 * If we are not going to support flow control
713 * option, then let peer know that we can't
714 * change the flow control characters.
715 */
716 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
717 slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
718 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
719 slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
720 break;
721
722 #ifdef AUTHENTICATION
723 case TELOPT_AUTHENTICATION:
724 auth_finished(0, AUTH_REJECT);
725 break;
726 #endif
727
728 /*
729 * For options that we might spin waiting for
730 * sub-negotiation, if the client turns off the
731 * option rather than responding to the request,
732 * we have to treat it here as if we got a response
733 * to the sub-negotiation, (by updating the timers)
734 * so that we'll break out of the loop.
735 */
736 case TELOPT_TTYPE:
737 settimer(ttypesubopt);
738 break;
739
740 case TELOPT_TSPEED:
741 settimer(tspeedsubopt);
742 break;
743
744 case TELOPT_XDISPLOC:
745 settimer(xdisplocsubopt);
746 break;
747
748 case TELOPT_OLD_ENVIRON:
749 settimer(oenvironsubopt);
750 break;
751
752 case TELOPT_NEW_ENVIRON:
753 settimer(environsubopt);
754 break;
755
756 default:
757 break;
758 }
759 set_his_want_state_wont(option);
760 if (his_state_is_will(option))
761 send_dont(option, 0);
762 } else {
763 switch (option) {
764 case TELOPT_TM:
765 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
766 if (lmodetype < NO_AUTOKLUDGE) {
767 lmodetype = NO_LINEMODE;
768 clientstat(TELOPT_LINEMODE, WONT, 0);
769 send_will(TELOPT_SGA, 1);
770 send_will(TELOPT_ECHO, 1);
771 }
772 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
773 break;
774
775 #ifdef AUTHENTICATION
776 case TELOPT_AUTHENTICATION:
777 auth_finished(0, AUTH_REJECT);
778 break;
779 #endif
780 default:
781 break;
782 }
783 }
784 }
785 set_his_state_wont(option);
786
787 } /* end of wontoption */
788
789 void
send_will(int option,int init)790 send_will(int option, int init)
791 {
792 if (init) {
793 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
794 my_want_state_is_will(option))
795 return;
796 set_my_want_state_will(option);
797 will_wont_resp[option]++;
798 }
799 (void) output_data("%c%c%c", IAC, WILL, option);
800
801 DIAG(TD_OPTIONS, printoption("td: send will", option));
802 }
803
804 #if !defined(LINEMODE) || !defined(KLUDGELINEMODE)
805 /*
806 * When we get a DONT SGA, we will try once to turn it
807 * back on. If the other side responds DONT SGA, we
808 * leave it at that. This is so that when we talk to
809 * clients that understand KLUDGELINEMODE but not LINEMODE,
810 * we'll keep them in char-at-a-time mode.
811 */
812 int turn_on_sga = 0;
813 #endif
814
815 void
dooption(int option)816 dooption(int option)
817 {
818 int changeok = 0;
819
820 /*
821 * Process client input.
822 */
823
824 DIAG(TD_OPTIONS, printoption("td: recv do", option));
825
826 if (will_wont_resp[option]) {
827 will_wont_resp[option]--;
828 if (will_wont_resp[option] && my_state_is_will(option))
829 will_wont_resp[option]--;
830 }
831 if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
832 switch (option) {
833 case TELOPT_ECHO:
834 #ifdef LINEMODE
835 # ifdef KLUDGELINEMODE
836 if (lmodetype == NO_LINEMODE)
837 # else
838 if (his_state_is_wont(TELOPT_LINEMODE))
839 # endif
840 #endif
841 {
842 init_termbuf();
843 tty_setecho(1);
844 set_termbuf();
845 }
846 changeok++;
847 break;
848
849 case TELOPT_BINARY:
850 init_termbuf();
851 tty_binaryout(1);
852 set_termbuf();
853 changeok++;
854 break;
855
856 case TELOPT_SGA:
857 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
858 /*
859 * If kludge linemode is in use, then we must
860 * process an incoming do SGA for linemode
861 * purposes.
862 */
863 if (lmodetype == KLUDGE_LINEMODE) {
864 /*
865 * Receipt of "do SGA" in kludge
866 * linemode is the peer asking us to
867 * turn off linemode. Make note of
868 * the request.
869 */
870 clientstat(TELOPT_LINEMODE, WONT, 0);
871 /*
872 * If linemode did not get turned off
873 * then don't tell peer that we did.
874 * Breaking here forces a wont SGA to
875 * be returned.
876 */
877 if (linemode)
878 break;
879 }
880 #else
881 turn_on_sga = 0;
882 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
883 changeok++;
884 break;
885
886 case TELOPT_STATUS:
887 changeok++;
888 break;
889
890 case TELOPT_TM:
891 /*
892 * Special case for TM. We send a WILL, but
893 * pretend we sent a WONT.
894 */
895 send_will(option, 0);
896 set_my_want_state_wont(option);
897 set_my_state_wont(option);
898 return;
899
900 case TELOPT_LOGOUT:
901 /*
902 * When we get a LOGOUT option, respond
903 * with a WILL LOGOUT, make sure that
904 * it gets written out to the network,
905 * and then just go away...
906 */
907 set_my_want_state_will(TELOPT_LOGOUT);
908 send_will(TELOPT_LOGOUT, 0);
909 set_my_state_will(TELOPT_LOGOUT);
910 (void)netflush();
911 cleanup(0);
912 /* NOT REACHED */
913 break;
914
915 #ifdef ENCRYPTION
916 case TELOPT_ENCRYPT:
917 changeok++;
918 break;
919 #endif /* ENCRYPTION */
920
921 case TELOPT_LINEMODE:
922 case TELOPT_TTYPE:
923 case TELOPT_NAWS:
924 case TELOPT_TSPEED:
925 case TELOPT_LFLOW:
926 case TELOPT_XDISPLOC:
927 case TELOPT_OLD_ENVIRON:
928 default:
929 break;
930 }
931 if (changeok) {
932 set_my_want_state_will(option);
933 send_will(option, 0);
934 } else {
935 will_wont_resp[option]++;
936 send_wont(option, 0);
937 }
938 }
939 set_my_state_will(option);
940
941 } /* end of dooption */
942
943 void
send_wont(int option,int init)944 send_wont(int option, int init)
945 {
946 if (init) {
947 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
948 my_want_state_is_wont(option))
949 return;
950 set_my_want_state_wont(option);
951 will_wont_resp[option]++;
952 }
953 (void) output_data("%c%c%c", IAC, WONT, option);
954
955 DIAG(TD_OPTIONS, printoption("td: send wont", option));
956 }
957
958 void
dontoption(int option)959 dontoption(int option)
960 {
961 /*
962 * Process client input.
963 */
964
965
966 DIAG(TD_OPTIONS, printoption("td: recv dont", option));
967
968 if (will_wont_resp[option]) {
969 will_wont_resp[option]--;
970 if (will_wont_resp[option] && my_state_is_wont(option))
971 will_wont_resp[option]--;
972 }
973 if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
974 switch (option) {
975 case TELOPT_BINARY:
976 init_termbuf();
977 tty_binaryout(0);
978 set_termbuf();
979 break;
980
981 case TELOPT_ECHO: /* we should stop echoing */
982 #ifdef LINEMODE
983 # ifdef KLUDGELINEMODE
984 if ((lmodetype != REAL_LINEMODE) &&
985 (lmodetype != KLUDGE_LINEMODE))
986 # else
987 if (his_state_is_wont(TELOPT_LINEMODE))
988 # endif
989 #endif
990 {
991 init_termbuf();
992 tty_setecho(0);
993 set_termbuf();
994 }
995 break;
996
997 case TELOPT_SGA:
998 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
999 /*
1000 * If kludge linemode is in use, then we
1001 * must process an incoming do SGA for
1002 * linemode purposes.
1003 */
1004 if ((lmodetype == KLUDGE_LINEMODE) ||
1005 (lmodetype == KLUDGE_OK)) {
1006 /*
1007 * The client is asking us to turn
1008 * linemode on.
1009 */
1010 lmodetype = KLUDGE_LINEMODE;
1011 clientstat(TELOPT_LINEMODE, WILL, 0);
1012 /*
1013 * If we did not turn line mode on,
1014 * then what do we say? Will SGA?
1015 * This violates design of telnet.
1016 * Gross. Very Gross.
1017 */
1018 }
1019 break;
1020 #else
1021 set_my_want_state_wont(option);
1022 if (my_state_is_will(option))
1023 send_wont(option, 0);
1024 set_my_state_wont(option);
1025 if (turn_on_sga ^= 1)
1026 send_will(option, 1);
1027 return;
1028 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1029
1030 default:
1031 break;
1032 }
1033
1034 set_my_want_state_wont(option);
1035 if (my_state_is_will(option))
1036 send_wont(option, 0);
1037 }
1038 set_my_state_wont(option);
1039
1040 } /* end of dontoption */
1041
1042 #ifdef ENV_HACK
1043 int env_ovar = -1;
1044 int env_ovalue = -1;
1045 #else /* ENV_HACK */
1046 # define env_ovar OLD_ENV_VAR
1047 # define env_ovalue OLD_ENV_VALUE
1048 #endif /* ENV_HACK */
1049
1050 /* envvarok(char*) */
1051 /* check that variable is safe to pass to login or shell */
1052 static int
envvarok(char * varp)1053 envvarok(char *varp)
1054 {
1055
1056 if (strcmp(varp, "TERMCAP") && /* to prevent a security hole */
1057 strcmp(varp, "TERMINFO") && /* with tgetent */
1058 strcmp(varp, "TERMPATH") &&
1059 strcmp(varp, "HOME") && /* to prevent the tegetent bug */
1060 strncmp(varp, "LD_", strlen("LD_")) && /* most systems */
1061 strncmp(varp, "_RLD_", strlen("_RLD_")) && /* IRIX */
1062 strcmp(varp, "LIBPATH") && /* AIX */
1063 strcmp(varp, "ENV") &&
1064 strcmp(varp, "BASH_ENV") &&
1065 strcmp(varp, "IFS") &&
1066 strncmp(varp, "KRB5", strlen("KRB5")) && /* Krb5 */
1067 /*
1068 * The above case is a catch-all for now. Here are some of
1069 * the specific ones we must avoid passing, at least until
1070 * we can prove it can be done safely. Keep this list
1071 * around un case someone wants to remove the catch-all.
1072 */
1073 strcmp(varp, "KRB5_CONFIG") && /* Krb5 */
1074 strcmp(varp, "KRB5CCNAME") && /* Krb5 */
1075 strcmp(varp, "KRB5_KTNAME") && /* Krb5 */
1076 strcmp(varp, "KRBTKFILE") && /* Krb4 */
1077 strcmp(varp, "KRB_CONF") && /* CNS 4 */
1078 strcmp(varp, "KRB_REALMS") && /* CNS 4 */
1079 strcmp(varp, "RESOLV_HOST_CONF")) /* Linux */
1080 return (1);
1081 else {
1082 syslog(LOG_INFO, "Rejected the attempt to modify the "
1083 "environment variable \"%s\"", varp);
1084 return (0);
1085 }
1086 }
1087
1088 /*
1089 * suboption()
1090 *
1091 * Look at the sub-option buffer, and try to be helpful to the other
1092 * side.
1093 *
1094 * Currently we recognize:
1095 *
1096 * Terminal type is
1097 * Linemode
1098 * Window size
1099 * Terminal speed
1100 */
1101 void
suboption(void)1102 suboption(void)
1103 {
1104 int subchar;
1105
1106 DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1107
1108 subchar = SB_GET();
1109 switch (subchar) {
1110 case TELOPT_TSPEED: {
1111 int xspeed, rspeed;
1112
1113 if (his_state_is_wont(TELOPT_TSPEED)) /* Ignore if option disabled */
1114 break;
1115
1116 settimer(tspeedsubopt);
1117
1118 if (SB_EOF() || SB_GET() != TELQUAL_IS)
1119 return;
1120
1121 xspeed = atoi((char *)subpointer);
1122
1123 while (SB_GET() != ',' && !SB_EOF());
1124 if (SB_EOF())
1125 return;
1126
1127 rspeed = atoi((char *)subpointer);
1128 clientstat(TELOPT_TSPEED, xspeed, rspeed);
1129
1130 break;
1131
1132 } /* end of case TELOPT_TSPEED */
1133
1134 case TELOPT_TTYPE: { /* Yaaaay! */
1135 char *p;
1136
1137 if (his_state_is_wont(TELOPT_TTYPE)) /* Ignore if option disabled */
1138 break;
1139 settimer(ttypesubopt);
1140
1141 if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1142 return; /* ??? XXX but, this is the most robust */
1143 }
1144
1145 p = terminaltype;
1146
1147 while ((p < (terminaltype + sizeof terminaltype-1)) &&
1148 !SB_EOF()) {
1149 int c;
1150
1151 c = SB_GET();
1152 if (isupper(c)) {
1153 c = tolower(c);
1154 }
1155 *p++ = c; /* accumulate name */
1156 }
1157 *p = 0;
1158 break;
1159 } /* end of case TELOPT_TTYPE */
1160
1161 case TELOPT_NAWS: {
1162 int xwinsize, ywinsize;
1163
1164 if (his_state_is_wont(TELOPT_NAWS)) /* Ignore if option disabled */
1165 break;
1166
1167 if (SB_EOF())
1168 return;
1169 xwinsize = SB_GET() << 8;
1170 if (SB_EOF())
1171 return;
1172 xwinsize |= SB_GET();
1173 if (SB_EOF())
1174 return;
1175 ywinsize = SB_GET() << 8;
1176 if (SB_EOF())
1177 return;
1178 ywinsize |= SB_GET();
1179 clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1180
1181 break;
1182
1183 } /* end of case TELOPT_NAWS */
1184
1185 #ifdef LINEMODE
1186 case TELOPT_LINEMODE: {
1187 int request;
1188
1189 if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1190 break;
1191 /*
1192 * Process linemode suboptions.
1193 */
1194 if (SB_EOF())
1195 break; /* garbage was sent */
1196 request = SB_GET(); /* get will/wont */
1197
1198 if (SB_EOF())
1199 break; /* another garbage check */
1200
1201 if (request == LM_SLC) { /* SLC is not preceded by WILL or WONT */
1202 /*
1203 * Process suboption buffer of slc's
1204 */
1205 start_slc(1);
1206 do_opt_slc(subpointer, SB_LEN());
1207 (void) end_slc(0);
1208 break;
1209 } else if (request == LM_MODE) {
1210 if (SB_EOF())
1211 return;
1212 useeditmode = SB_GET(); /* get mode flag */
1213 clientstat(LM_MODE, 0, 0);
1214 break;
1215 }
1216
1217 if (SB_EOF())
1218 break;
1219 switch (SB_GET()) { /* what suboption? */
1220 case LM_FORWARDMASK:
1221 /*
1222 * According to spec, only server can send request for
1223 * forwardmask, and client can only return a positive response.
1224 * So don't worry about it.
1225 */
1226
1227 default:
1228 break;
1229 }
1230 break;
1231 } /* end of case TELOPT_LINEMODE */
1232 #endif
1233 case TELOPT_STATUS: {
1234 int mode;
1235
1236 if (SB_EOF())
1237 break;
1238 mode = SB_GET();
1239 switch (mode) {
1240 case TELQUAL_SEND:
1241 if (my_state_is_will(TELOPT_STATUS))
1242 send_status();
1243 break;
1244
1245 case TELQUAL_IS:
1246 break;
1247
1248 default:
1249 break;
1250 }
1251 break;
1252 } /* end of case TELOPT_STATUS */
1253
1254 case TELOPT_XDISPLOC: {
1255 if (SB_EOF() || SB_GET() != TELQUAL_IS)
1256 return;
1257 settimer(xdisplocsubopt);
1258 subpointer[SB_LEN()] = '\0';
1259 (void)setenv("DISPLAY", (char *)subpointer, 1);
1260 break;
1261 } /* end of case TELOPT_XDISPLOC */
1262
1263 case TELOPT_NEW_ENVIRON:
1264 case TELOPT_OLD_ENVIRON: {
1265 int c;
1266 char *cp, *varp, *valp;
1267
1268 if (SB_EOF())
1269 return;
1270 c = SB_GET();
1271 if (c == TELQUAL_IS) {
1272 if (subchar == TELOPT_OLD_ENVIRON)
1273 settimer(oenvironsubopt);
1274 else
1275 settimer(environsubopt);
1276 } else if (c != TELQUAL_INFO) {
1277 return;
1278 }
1279
1280 if (subchar == TELOPT_NEW_ENVIRON) {
1281 while (!SB_EOF()) {
1282 c = SB_GET();
1283 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1284 break;
1285 }
1286 } else
1287 {
1288 #ifdef ENV_HACK
1289 /*
1290 * We only want to do this if we haven't already decided
1291 * whether or not the other side has its VALUE and VAR
1292 * reversed.
1293 */
1294 if (env_ovar < 0) {
1295 int last = -1; /* invalid value */
1296 int empty = 0;
1297 int got_var = 0, got_value = 0, got_uservar = 0;
1298
1299 /*
1300 * The other side might have its VALUE and VAR values
1301 * reversed. To be interoperable, we need to determine
1302 * which way it is. If the first recognized character
1303 * is a VAR or VALUE, then that will tell us what
1304 * type of client it is. If the first recognized
1305 * character is a USERVAR, then we continue scanning
1306 * the suboption looking for two consecutive
1307 * VAR or VALUE fields. We should not get two
1308 * consecutive VALUE fields, so finding two
1309 * consecutive VALUE or VAR fields will tell us
1310 * what the client is.
1311 */
1312 SB_SAVE();
1313 while (!SB_EOF()) {
1314 c = SB_GET();
1315 switch(c) {
1316 case OLD_ENV_VAR:
1317 if (last < 0 || last == OLD_ENV_VAR
1318 || (empty && (last == OLD_ENV_VALUE)))
1319 goto env_ovar_ok;
1320 got_var++;
1321 last = OLD_ENV_VAR;
1322 break;
1323 case OLD_ENV_VALUE:
1324 if (last < 0 || last == OLD_ENV_VALUE
1325 || (empty && (last == OLD_ENV_VAR)))
1326 goto env_ovar_wrong;
1327 got_value++;
1328 last = OLD_ENV_VALUE;
1329 break;
1330 case ENV_USERVAR:
1331 /* count strings of USERVAR as one */
1332 if (last != ENV_USERVAR)
1333 got_uservar++;
1334 if (empty) {
1335 if (last == OLD_ENV_VALUE)
1336 goto env_ovar_ok;
1337 if (last == OLD_ENV_VAR)
1338 goto env_ovar_wrong;
1339 }
1340 last = ENV_USERVAR;
1341 break;
1342 case ENV_ESC:
1343 if (!SB_EOF())
1344 c = SB_GET();
1345 /* FALL THROUGH */
1346 default:
1347 empty = 0;
1348 continue;
1349 }
1350 empty = 1;
1351 }
1352 if (empty) {
1353 if (last == OLD_ENV_VALUE)
1354 goto env_ovar_ok;
1355 if (last == OLD_ENV_VAR)
1356 goto env_ovar_wrong;
1357 }
1358 /*
1359 * Ok, the first thing was a USERVAR, and there
1360 * are not two consecutive VAR or VALUE commands,
1361 * and none of the VAR or VALUE commands are empty.
1362 * If the client has sent us a well-formed option,
1363 * then the number of VALUEs received should always
1364 * be less than or equal to the number of VARs and
1365 * USERVARs received.
1366 *
1367 * If we got exactly as many VALUEs as VARs and
1368 * USERVARs, the client has the same definitions.
1369 *
1370 * If we got exactly as many VARs as VALUEs and
1371 * USERVARS, the client has reversed definitions.
1372 */
1373 if (got_uservar + got_var == got_value) {
1374 env_ovar_ok:
1375 env_ovar = OLD_ENV_VAR;
1376 env_ovalue = OLD_ENV_VALUE;
1377 } else if (got_uservar + got_value == got_var) {
1378 env_ovar_wrong:
1379 env_ovar = OLD_ENV_VALUE;
1380 env_ovalue = OLD_ENV_VAR;
1381 DIAG(TD_OPTIONS, {output_data(
1382 "ENVIRON VALUE and VAR are reversed!\r\n");});
1383
1384 }
1385 }
1386 SB_RESTORE();
1387 #endif
1388
1389 while (!SB_EOF()) {
1390 c = SB_GET();
1391 if ((c == env_ovar) || (c == ENV_USERVAR))
1392 break;
1393 }
1394 }
1395
1396 if (SB_EOF())
1397 return;
1398
1399 cp = varp = (char *)subpointer;
1400 valp = 0;
1401
1402 while (!SB_EOF()) {
1403 c = SB_GET();
1404 if (subchar == TELOPT_OLD_ENVIRON) {
1405 if (c == env_ovar)
1406 c = NEW_ENV_VAR;
1407 else if (c == env_ovalue)
1408 c = NEW_ENV_VALUE;
1409 }
1410 switch (c) {
1411
1412 case NEW_ENV_VALUE:
1413 *cp = '\0';
1414 cp = valp = (char *)subpointer;
1415 break;
1416
1417 case NEW_ENV_VAR:
1418 case ENV_USERVAR:
1419 *cp = '\0';
1420 if (envvarok(varp)) {
1421 if (valp)
1422 (void)setenv(varp, valp, 1);
1423 else
1424 unsetenv(varp);
1425 }
1426 cp = varp = (char *)subpointer;
1427 valp = 0;
1428 break;
1429
1430 case ENV_ESC:
1431 if (SB_EOF())
1432 break;
1433 c = SB_GET();
1434 /* FALL THROUGH */
1435 default:
1436 *cp++ = c;
1437 break;
1438 }
1439 }
1440 *cp = '\0';
1441 if (envvarok(varp)) {
1442 if (valp)
1443 (void)setenv(varp, valp, 1);
1444 else
1445 unsetenv(varp);
1446 }
1447 break;
1448 } /* end of case TELOPT_NEW_ENVIRON */
1449 #ifdef AUTHENTICATION
1450 case TELOPT_AUTHENTICATION:
1451 if (SB_EOF())
1452 break;
1453 switch(SB_GET()) {
1454 case TELQUAL_SEND:
1455 case TELQUAL_REPLY:
1456 /*
1457 * These are sent by us and cannot be sent by
1458 * the client.
1459 */
1460 break;
1461 case TELQUAL_IS:
1462 auth_is(subpointer, SB_LEN());
1463 break;
1464 case TELQUAL_NAME:
1465 auth_name(subpointer, SB_LEN());
1466 break;
1467 }
1468 break;
1469 #endif
1470 #ifdef ENCRYPTION
1471 case TELOPT_ENCRYPT:
1472 if (SB_EOF())
1473 break;
1474 switch(SB_GET()) {
1475 case ENCRYPT_SUPPORT:
1476 encrypt_support(subpointer, SB_LEN());
1477 break;
1478 case ENCRYPT_IS:
1479 encrypt_is(subpointer, SB_LEN());
1480 break;
1481 case ENCRYPT_REPLY:
1482 encrypt_reply(subpointer, SB_LEN());
1483 break;
1484 case ENCRYPT_START:
1485 encrypt_start(subpointer, SB_LEN());
1486 break;
1487 case ENCRYPT_END:
1488 encrypt_end();
1489 break;
1490 case ENCRYPT_REQSTART:
1491 encrypt_request_start(subpointer, SB_LEN());
1492 break;
1493 case ENCRYPT_REQEND:
1494 /*
1495 * We can always send an REQEND so that we cannot
1496 * get stuck encrypting. We should only get this
1497 * if we have been able to get in the correct mode
1498 * anyhow.
1499 */
1500 encrypt_request_end();
1501 break;
1502 case ENCRYPT_ENC_KEYID:
1503 encrypt_enc_keyid(subpointer, SB_LEN());
1504 break;
1505 case ENCRYPT_DEC_KEYID:
1506 encrypt_dec_keyid(subpointer, SB_LEN());
1507 break;
1508 default:
1509 break;
1510 }
1511 break;
1512 #endif /* ENCRYPTION */
1513
1514 default:
1515 break;
1516 } /* end of switch */
1517
1518 } /* end of suboption */
1519
1520 #ifdef LINEMODE
1521 void
doclientstat(void)1522 doclientstat(void)
1523 {
1524 clientstat(TELOPT_LINEMODE, WILL, 0);
1525 }
1526 #endif /* LINEMODE */
1527
1528 void
send_status(void)1529 send_status(void)
1530 {
1531 #define ADD(c) \
1532 do { \
1533 if (ep > ncp) \
1534 *ncp++ = c; \
1535 else \
1536 goto trunc; \
1537 } while (0)
1538 #define ADD_DATA(c) \
1539 do { \
1540 ADD(c); if (c == SE || c == IAC) ADD(c); \
1541 } while (0)
1542
1543 unsigned char statusbuf[256];
1544 unsigned char *ep;
1545 unsigned char *ncp;
1546 unsigned char i;
1547
1548 ncp = statusbuf;
1549 ep = statusbuf + sizeof(statusbuf);
1550
1551 netflush(); /* get rid of anything waiting to go out */
1552
1553 ADD(IAC);
1554 ADD(SB);
1555 ADD(TELOPT_STATUS);
1556 ADD(TELQUAL_IS);
1557
1558 /*
1559 * We check the want_state rather than the current state,
1560 * because if we received a DO/WILL for an option that we
1561 * don't support, and the other side didn't send a DONT/WONT
1562 * in response to our WONT/DONT, then the "state" will be
1563 * WILL/DO, and the "want_state" will be WONT/DONT. We
1564 * need to go by the latter.
1565 */
1566 for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1567 if (my_want_state_is_will(i)) {
1568 ADD(WILL);
1569 ADD_DATA(i);
1570 }
1571 if (his_want_state_is_will(i)) {
1572 ADD(DO);
1573 ADD_DATA(i);
1574 }
1575 }
1576
1577 if (his_want_state_is_will(TELOPT_LFLOW)) {
1578 ADD(SB);
1579 ADD(TELOPT_LFLOW);
1580 if (flowmode) {
1581 ADD(LFLOW_ON);
1582 } else {
1583 ADD(LFLOW_OFF);
1584 }
1585 ADD(SE);
1586
1587 if (restartany >= 0) {
1588 ADD(SB);
1589 ADD(TELOPT_LFLOW);
1590 if (restartany) {
1591 ADD(LFLOW_RESTART_ANY);
1592 } else {
1593 ADD(LFLOW_RESTART_XON);
1594 }
1595 ADD(SE);
1596 }
1597 }
1598
1599 #ifdef LINEMODE
1600 if (his_want_state_is_will(TELOPT_LINEMODE)) {
1601 unsigned char *cp, *cpe;
1602 int len;
1603
1604 ADD(SB);
1605 ADD(TELOPT_LINEMODE);
1606 ADD(LM_MODE);
1607 ADD_DATA(editmode);
1608 ADD(SE);
1609
1610 ADD(SB);
1611 ADD(TELOPT_LINEMODE);
1612 ADD(LM_SLC);
1613 start_slc(0);
1614 send_slc();
1615 len = end_slc(&cp);
1616 for (cpe = cp + len; cp < cpe; cp++)
1617 ADD_DATA(*cp);
1618 ADD(SE);
1619 }
1620 #endif /* LINEMODE */
1621
1622 ADD(IAC);
1623 ADD(SE);
1624
1625 writenet(statusbuf, ncp - statusbuf);
1626 netflush(); /* Send it on its way */
1627
1628 DIAG(TD_OPTIONS,
1629 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1630 return;
1631
1632 trunc:
1633 /* XXX bark? */
1634 return;
1635 #undef ADD
1636 #undef ADD_DATA
1637 }
1638
1639 int
output_data(const char * format,...)1640 output_data(const char *format, ...)
1641 {
1642 va_list args;
1643 size_t remaining, ret;
1644
1645 va_start(args, format);
1646 remaining = BUFSIZ - (nfrontp - netobuf);
1647 /* try a netflush() if the room is too low */
1648 if (strlen(format) > remaining || BUFSIZ / 4 > remaining) {
1649 netflush();
1650 remaining = BUFSIZ - (nfrontp - netobuf);
1651 }
1652 ret = vsnprintf(nfrontp, remaining, format, args);
1653 nfrontp += ((ret < remaining - 1) ? ret : remaining - 1);
1654 va_end(args);
1655 return ret;
1656 }
1657
1658 int
output_datalen(const char * buf,size_t l)1659 output_datalen(const char *buf, size_t l)
1660 {
1661 size_t remaining;
1662
1663 remaining = BUFSIZ - (nfrontp - netobuf);
1664 if (remaining < l) {
1665 netflush();
1666 remaining = BUFSIZ - (nfrontp - netobuf);
1667 }
1668 if (remaining < l)
1669 return -1;
1670 memmove(nfrontp, buf, l);
1671 nfrontp += l;
1672 return (int)l;
1673 }
1674