Merge branch 'vendor/GMP'
[dragonfly.git] / libexec / telnetd / state.c
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/crypto/telnet/telnetd/state.c,v 1.4.2.3 2002/04/13 10:59:08 markm Exp $
35  * $DragonFly: src/crypto/telnet/telnetd/state.c,v 1.3 2006/01/17 23:50:35 dillon Exp $
36  */
37
38 #include <stdarg.h>
39 #include "telnetd.h"
40 #ifdef  AUTHENTICATION
41 #include <libtelnet/auth.h>
42 #endif
43 #ifdef  ENCRYPTION
44 #include <libtelnet/encrypt.h>
45 #endif
46
47 static int envvarok(char *);
48
49 unsigned char   doopt[] = { IAC, DO, '%', 'c', 0 };
50 unsigned char   dont[] = { IAC, DONT, '%', 'c', 0 };
51 unsigned char   will[] = { IAC, WILL, '%', 'c', 0 };
52 unsigned char   wont[] = { IAC, WONT, '%', 'c', 0 };
53 int     not42 = 1;
54
55 /*
56  * Buffer for sub-options, and macros
57  * for suboptions buffer manipulations
58  */
59 unsigned char subbuffer[512], *subpointer= subbuffer, *subend= subbuffer;
60
61 #define SB_CLEAR()      subpointer = subbuffer
62 #define SB_TERM()       { subend = subpointer; SB_CLEAR(); }
63 #define SB_ACCUM(c)     if (subpointer < (subbuffer+sizeof subbuffer)) { \
64                                 *subpointer++ = (c); \
65                         }
66 #define SB_GET()        ((*subpointer++)&0xff)
67 #define SB_EOF()        (subpointer >= subend)
68 #define SB_LEN()        (subend - subpointer)
69
70 #ifdef  ENV_HACK
71 unsigned char *subsave;
72 #define SB_SAVE()       subsave = subpointer;
73 #define SB_RESTORE()    subpointer = subsave;
74 #endif
75
76
77 /*
78  * State for recv fsm
79  */
80 #define TS_DATA         0       /* base state */
81 #define TS_IAC          1       /* look for double IAC's */
82 #define TS_CR           2       /* CR-LF ->'s CR */
83 #define TS_SB           3       /* throw away begin's... */
84 #define TS_SE           4       /* ...end's (suboption negotiation) */
85 #define TS_WILL         5       /* will option negotiation */
86 #define TS_WONT         6       /* wont " */
87 #define TS_DO           7       /* do " */
88 #define TS_DONT         8       /* dont " */
89
90 static void doclientstat(void);
91
92 void
93 telrcv(void)
94 {
95         int c;
96         static int state = TS_DATA;
97
98         while (ncc > 0) {
99                 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
100                         break;
101                 c = *netip++ & 0377, ncc--;
102 #ifdef  ENCRYPTION
103                 if (decrypt_input)
104                         c = (*decrypt_input)(c);
105 #endif  /* ENCRYPTION */
106                 switch (state) {
107
108                 case TS_CR:
109                         state = TS_DATA;
110                         /* Strip off \n or \0 after a \r */
111                         if ((c == 0) || (c == '\n')) {
112                                 break;
113                         }
114                         /* FALL THROUGH */
115
116                 case TS_DATA:
117                         if (c == IAC) {
118                                 state = TS_IAC;
119                                 break;
120                         }
121                         /*
122                          * We now map \r\n ==> \r for pragmatic reasons.
123                          * Many client implementations send \r\n when
124                          * the user hits the CarriageReturn key.
125                          *
126                          * We USED to map \r\n ==> \n, since \r\n says
127                          * that we want to be in column 1 of the next
128                          * printable line, and \n is the standard
129                          * unix way of saying that (\r is only good
130                          * if CRMOD is set, which it normally is).
131                          */
132                         if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
133                                 int nc = *netip;
134 #ifdef  ENCRYPTION
135                                 if (decrypt_input)
136                                         nc = (*decrypt_input)(nc & 0xff);
137 #endif  /* ENCRYPTION */
138 #ifdef  LINEMODE
139                                 /*
140                                  * If we are operating in linemode,
141                                  * convert to local end-of-line.
142                                  */
143                                 if (linemode && (ncc > 0) && (('\n' == nc) ||
144                                          ((0 == nc) && tty_iscrnl())) ) {
145                                         netip++; ncc--;
146                                         c = '\n';
147                                 } else
148 #endif
149                                 {
150 #ifdef  ENCRYPTION
151                                         if (decrypt_input)
152                                                 (void)(*decrypt_input)(-1);
153 #endif  /* ENCRYPTION */
154                                         state = TS_CR;
155                                 }
156                         }
157                         *pfrontp++ = c;
158                         break;
159
160                 case TS_IAC:
161 gotiac:                 switch (c) {
162
163                         /*
164                          * Send the process on the pty side an
165                          * interrupt.  Do this with a NULL or
166                          * interrupt char; depending on the tty mode.
167                          */
168                         case IP:
169                                 DIAG(TD_OPTIONS,
170                                         printoption("td: recv IAC", c));
171                                 interrupt();
172                                 break;
173
174                         case BREAK:
175                                 DIAG(TD_OPTIONS,
176                                         printoption("td: recv IAC", c));
177                                 sendbrk();
178                                 break;
179
180                         /*
181                          * Are You There?
182                          */
183                         case AYT:
184                                 DIAG(TD_OPTIONS,
185                                         printoption("td: recv IAC", c));
186                                 recv_ayt();
187                                 break;
188
189                         /*
190                          * Abort Output
191                          */
192                         case AO:
193                             {
194                                 DIAG(TD_OPTIONS,
195                                         printoption("td: recv IAC", c));
196                                 ptyflush();     /* half-hearted */
197                                 init_termbuf();
198
199                                 if (slctab[SLC_AO].sptr &&
200                                     *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
201                                     *pfrontp++ =
202                                         (unsigned char)*slctab[SLC_AO].sptr;
203                                 }
204
205                                 netclear();     /* clear buffer back */
206                                 output_data("%c%c", IAC, DM);
207                                 neturg = nfrontp-1; /* off by one XXX */
208                                 DIAG(TD_OPTIONS,
209                                         printoption("td: send IAC", DM));
210                                 break;
211                             }
212
213                         /*
214                          * Erase Character and
215                          * Erase Line
216                          */
217                         case EC:
218                         case EL:
219                             {
220                                 cc_t ch;
221
222                                 DIAG(TD_OPTIONS,
223                                         printoption("td: recv IAC", c));
224                                 ptyflush();     /* half-hearted */
225                                 init_termbuf();
226                                 if (c == EC)
227                                         ch = *slctab[SLC_EC].sptr;
228                                 else
229                                         ch = *slctab[SLC_EL].sptr;
230                                 if (ch != (cc_t)(_POSIX_VDISABLE))
231                                         *pfrontp++ = (unsigned char)ch;
232                                 break;
233                             }
234
235                         /*
236                          * Check for urgent data...
237                          */
238                         case DM:
239                                 DIAG(TD_OPTIONS,
240                                         printoption("td: recv IAC", c));
241                                 SYNCHing = stilloob(net);
242                                 settimer(gotDM);
243                                 break;
244
245
246                         /*
247                          * Begin option subnegotiation...
248                          */
249                         case SB:
250                                 state = TS_SB;
251                                 SB_CLEAR();
252                                 continue;
253
254                         case WILL:
255                                 state = TS_WILL;
256                                 continue;
257
258                         case WONT:
259                                 state = TS_WONT;
260                                 continue;
261
262                         case DO:
263                                 state = TS_DO;
264                                 continue;
265
266                         case DONT:
267                                 state = TS_DONT;
268                                 continue;
269                         case EOR:
270                                 if (his_state_is_will(TELOPT_EOR))
271                                         doeof();
272                                 break;
273
274                         /*
275                          * Handle RFC 10xx Telnet linemode option additions
276                          * to command stream (EOF, SUSP, ABORT).
277                          */
278                         case xEOF:
279                                 doeof();
280                                 break;
281
282                         case SUSP:
283                                 sendsusp();
284                                 break;
285
286                         case ABORT:
287                                 sendbrk();
288                                 break;
289
290                         case IAC:
291                                 *pfrontp++ = c;
292                                 break;
293                         }
294                         state = TS_DATA;
295                         break;
296
297                 case TS_SB:
298                         if (c == IAC) {
299                                 state = TS_SE;
300                         } else {
301                                 SB_ACCUM(c);
302                         }
303                         break;
304
305                 case TS_SE:
306                         if (c != SE) {
307                                 if (c != IAC) {
308                                         /*
309                                          * bad form of suboption negotiation.
310                                          * handle it in such a way as to avoid
311                                          * damage to local state.  Parse
312                                          * suboption buffer found so far,
313                                          * then treat remaining stream as
314                                          * another command sequence.
315                                          */
316
317                                         /* for DIAGNOSTICS */
318                                         SB_ACCUM(IAC);
319                                         SB_ACCUM(c);
320                                         subpointer -= 2;
321
322                                         SB_TERM();
323                                         suboption();
324                                         state = TS_IAC;
325                                         goto gotiac;
326                                 }
327                                 SB_ACCUM(c);
328                                 state = TS_SB;
329                         } else {
330                                 /* for DIAGNOSTICS */
331                                 SB_ACCUM(IAC);
332                                 SB_ACCUM(SE);
333                                 subpointer -= 2;
334
335                                 SB_TERM();
336                                 suboption();    /* handle sub-option */
337                                 state = TS_DATA;
338                         }
339                         break;
340
341                 case TS_WILL:
342                         willoption(c);
343                         state = TS_DATA;
344                         continue;
345
346                 case TS_WONT:
347                         wontoption(c);
348                         state = TS_DATA;
349                         continue;
350
351                 case TS_DO:
352                         dooption(c);
353                         state = TS_DATA;
354                         continue;
355
356                 case TS_DONT:
357                         dontoption(c);
358                         state = TS_DATA;
359                         continue;
360
361                 default:
362                         syslog(LOG_ERR, "panic state=%d", state);
363                         printf("telnetd: panic state=%d\n", state);
364                         exit(1);
365                 }
366         }
367 }  /* end of telrcv */
368
369 /*
370  * The will/wont/do/dont state machines are based on Dave Borman's
371  * Telnet option processing state machine.
372  *
373  * These correspond to the following states:
374  *      my_state = the last negotiated state
375  *      want_state = what I want the state to go to
376  *      want_resp = how many requests I have sent
377  * All state defaults are negative, and resp defaults to 0.
378  *
379  * When initiating a request to change state to new_state:
380  *
381  * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
382  *      do nothing;
383  * } else {
384  *      want_state = new_state;
385  *      send new_state;
386  *      want_resp++;
387  * }
388  *
389  * When receiving new_state:
390  *
391  * if (want_resp) {
392  *      want_resp--;
393  *      if (want_resp && (new_state == my_state))
394  *              want_resp--;
395  * }
396  * if ((want_resp == 0) && (new_state != want_state)) {
397  *      if (ok_to_switch_to new_state)
398  *              want_state = new_state;
399  *      else
400  *              want_resp++;
401  *      send want_state;
402  * }
403  * my_state = new_state;
404  *
405  * Note that new_state is implied in these functions by the function itself.
406  * will and do imply positive new_state, wont and dont imply negative.
407  *
408  * Finally, there is one catch.  If we send a negative response to a
409  * positive request, my_state will be the positive while want_state will
410  * remain negative.  my_state will revert to negative when the negative
411  * acknowlegment arrives from the peer.  Thus, my_state generally tells
412  * us not only the last negotiated state, but also tells us what the peer
413  * wants to be doing as well.  It is important to understand this difference
414  * as we may wish to be processing data streams based on our desired state
415  * (want_state) or based on what the peer thinks the state is (my_state).
416  *
417  * This all works fine because if the peer sends a positive request, the data
418  * that we receive prior to negative acknowlegment will probably be affected
419  * by the positive state, and we can process it as such (if we can; if we
420  * can't then it really doesn't matter).  If it is that important, then the
421  * peer probably should be buffering until this option state negotiation
422  * is complete.
423  *
424  */
425 void
426 send_do(int option, int init)
427 {
428         if (init) {
429                 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
430                     his_want_state_is_will(option))
431                         return;
432                 /*
433                  * Special case for TELOPT_TM:  We send a DO, but pretend
434                  * that we sent a DONT, so that we can send more DOs if
435                  * we want to.
436                  */
437                 if (option == TELOPT_TM)
438                         set_his_want_state_wont(option);
439                 else
440                         set_his_want_state_will(option);
441                 do_dont_resp[option]++;
442         }
443         output_data((const char *)doopt, option);
444
445         DIAG(TD_OPTIONS, printoption("td: send do", option));
446 }
447
448 void
449 willoption(int option)
450 {
451         int changeok = 0;
452         void (*func)(void) = 0;
453
454         /*
455          * process input from peer.
456          */
457
458         DIAG(TD_OPTIONS, printoption("td: recv will", option));
459
460         if (do_dont_resp[option]) {
461                 do_dont_resp[option]--;
462                 if (do_dont_resp[option] && his_state_is_will(option))
463                         do_dont_resp[option]--;
464         }
465         if (do_dont_resp[option] == 0) {
466             if (his_want_state_is_wont(option)) {
467                 switch (option) {
468
469                 case TELOPT_BINARY:
470                         init_termbuf();
471                         tty_binaryin(1);
472                         set_termbuf();
473                         changeok++;
474                         break;
475
476                 case TELOPT_ECHO:
477                         /*
478                          * See comments below for more info.
479                          */
480                         not42 = 0;      /* looks like a 4.2 system */
481                         break;
482
483                 case TELOPT_TM:
484 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
485                         /*
486                          * This telnetd implementation does not really
487                          * support timing marks, it just uses them to
488                          * support the kludge linemode stuff.  If we
489                          * receive a will or wont TM in response to our
490                          * do TM request that may have been sent to
491                          * determine kludge linemode support, process
492                          * it, otherwise TM should get a negative
493                          * response back.
494                          */
495                         /*
496                          * Handle the linemode kludge stuff.
497                          * If we are not currently supporting any
498                          * linemode at all, then we assume that this
499                          * is the client telling us to use kludge
500                          * linemode in response to our query.  Set the
501                          * linemode type that is to be supported, note
502                          * that the client wishes to use linemode, and
503                          * eat the will TM as though it never arrived.
504                          */
505                         if (lmodetype < KLUDGE_LINEMODE) {
506                                 lmodetype = KLUDGE_LINEMODE;
507                                 clientstat(TELOPT_LINEMODE, WILL, 0);
508                                 send_wont(TELOPT_SGA, 1);
509                         } else if (lmodetype == NO_AUTOKLUDGE) {
510                                 lmodetype = KLUDGE_OK;
511                         }
512 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
513                         /*
514                          * We never respond to a WILL TM, and
515                          * we leave the state WONT.
516                          */
517                         return;
518
519                 case TELOPT_LFLOW:
520                         /*
521                          * If we are going to support flow control
522                          * option, then don't worry peer that we can't
523                          * change the flow control characters.
524                          */
525                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
526                         slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
527                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
528                         slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
529                 case TELOPT_TTYPE:
530                 case TELOPT_SGA:
531                 case TELOPT_NAWS:
532                 case TELOPT_TSPEED:
533                 case TELOPT_XDISPLOC:
534                 case TELOPT_NEW_ENVIRON:
535                 case TELOPT_OLD_ENVIRON:
536                         changeok++;
537                         break;
538
539 #ifdef  LINEMODE
540                 case TELOPT_LINEMODE:
541 # ifdef KLUDGELINEMODE
542                         /*
543                          * Note client's desire to use linemode.
544                          */
545                         lmodetype = REAL_LINEMODE;
546 # endif /* KLUDGELINEMODE */
547                         func = doclientstat;
548                         changeok++;
549                         break;
550 #endif  /* LINEMODE */
551
552 #ifdef  AUTHENTICATION
553                 case TELOPT_AUTHENTICATION:
554                         func = auth_request;
555                         changeok++;
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 propogated 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                 case TELOPT_LFLOW:
630                         func = flowstat;
631                         break;
632                 }
633             }
634         }
635         set_his_state_will(option);
636         if (func)
637                 (*func)();
638 }  /* end of willoption */
639
640 void
641 send_dont(int option, int init)
642 {
643         if (init) {
644                 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
645                     his_want_state_is_wont(option))
646                         return;
647                 set_his_want_state_wont(option);
648                 do_dont_resp[option]++;
649         }
650         output_data((const char *)dont, option);
651
652         DIAG(TD_OPTIONS, printoption("td: send dont", option));
653 }
654
655 void
656 wontoption(int option)
657 {
658         /*
659          * Process client input.
660          */
661
662         DIAG(TD_OPTIONS, printoption("td: recv wont", option));
663
664         if (do_dont_resp[option]) {
665                 do_dont_resp[option]--;
666                 if (do_dont_resp[option] && his_state_is_wont(option))
667                         do_dont_resp[option]--;
668         }
669         if (do_dont_resp[option] == 0) {
670             if (his_want_state_is_will(option)) {
671                 /* it is always ok to change to negative state */
672                 switch (option) {
673                 case TELOPT_ECHO:
674                         not42 = 1; /* doesn't seem to be a 4.2 system */
675                         break;
676
677                 case TELOPT_BINARY:
678                         init_termbuf();
679                         tty_binaryin(0);
680                         set_termbuf();
681                         break;
682
683 #ifdef  LINEMODE
684                 case TELOPT_LINEMODE:
685 # ifdef KLUDGELINEMODE
686                         /*
687                          * If real linemode is supported, then client is
688                          * asking to turn linemode off.
689                          */
690                         if (lmodetype != REAL_LINEMODE)
691                                 break;
692                         lmodetype = KLUDGE_LINEMODE;
693 # endif /* KLUDGELINEMODE */
694                         clientstat(TELOPT_LINEMODE, WONT, 0);
695                         break;
696 #endif  /* LINEMODE */
697
698                 case TELOPT_TM:
699                         /*
700                          * If we get a WONT TM, and had sent a DO TM,
701                          * don't respond with a DONT TM, just leave it
702                          * as is.  Short circut the state machine to
703                          * achive this.
704                          */
705                         set_his_want_state_wont(TELOPT_TM);
706                         return;
707
708                 case TELOPT_LFLOW:
709                         /*
710                          * If we are not going to support flow control
711                          * option, then let peer know that we can't
712                          * change the flow control characters.
713                          */
714                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
715                         slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
716                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
717                         slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
718                         break;
719
720 #ifdef  AUTHENTICATION
721                 case TELOPT_AUTHENTICATION:
722                         auth_finished(0, AUTH_REJECT);
723                         break;
724 #endif
725
726                 /*
727                  * For options that we might spin waiting for
728                  * sub-negotiation, if the client turns off the
729                  * option rather than responding to the request,
730                  * we have to treat it here as if we got a response
731                  * to the sub-negotiation, (by updating the timers)
732                  * so that we'll break out of the loop.
733                  */
734                 case TELOPT_TTYPE:
735                         settimer(ttypesubopt);
736                         break;
737
738                 case TELOPT_TSPEED:
739                         settimer(tspeedsubopt);
740                         break;
741
742                 case TELOPT_XDISPLOC:
743                         settimer(xdisplocsubopt);
744                         break;
745
746                 case TELOPT_OLD_ENVIRON:
747                         settimer(oenvironsubopt);
748                         break;
749
750                 case TELOPT_NEW_ENVIRON:
751                         settimer(environsubopt);
752                         break;
753
754                 default:
755                         break;
756                 }
757                 set_his_want_state_wont(option);
758                 if (his_state_is_will(option))
759                         send_dont(option, 0);
760             } else {
761                 switch (option) {
762                 case TELOPT_TM:
763 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
764                         if (lmodetype < NO_AUTOKLUDGE) {
765                                 lmodetype = NO_LINEMODE;
766                                 clientstat(TELOPT_LINEMODE, WONT, 0);
767                                 send_will(TELOPT_SGA, 1);
768                                 send_will(TELOPT_ECHO, 1);
769                         }
770 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
771                         break;
772
773 #ifdef AUTHENTICATION
774                 case TELOPT_AUTHENTICATION:
775                         auth_finished(0, AUTH_REJECT);
776                         break;
777 #endif
778                 default:
779                         break;
780                 }
781             }
782         }
783         set_his_state_wont(option);
784
785 }  /* end of wontoption */
786
787 void
788 send_will(int option, int init)
789 {
790         if (init) {
791                 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
792                     my_want_state_is_will(option))
793                         return;
794                 set_my_want_state_will(option);
795                 will_wont_resp[option]++;
796         }
797         output_data((const char *)will, option);
798
799         DIAG(TD_OPTIONS, printoption("td: send will", option));
800 }
801
802 #if     !defined(LINEMODE) || !defined(KLUDGELINEMODE)
803 /*
804  * When we get a DONT SGA, we will try once to turn it
805  * back on.  If the other side responds DONT SGA, we
806  * leave it at that.  This is so that when we talk to
807  * clients that understand KLUDGELINEMODE but not LINEMODE,
808  * we'll keep them in char-at-a-time mode.
809  */
810 int turn_on_sga = 0;
811 #endif
812
813 void
814 dooption(int option)
815 {
816         int changeok = 0;
817
818         /*
819          * Process client input.
820          */
821
822         DIAG(TD_OPTIONS, printoption("td: recv do", option));
823
824         if (will_wont_resp[option]) {
825                 will_wont_resp[option]--;
826                 if (will_wont_resp[option] && my_state_is_will(option))
827                         will_wont_resp[option]--;
828         }
829         if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
830                 switch (option) {
831                 case TELOPT_ECHO:
832 #ifdef  LINEMODE
833 # ifdef KLUDGELINEMODE
834                         if (lmodetype == NO_LINEMODE)
835 # else
836                         if (his_state_is_wont(TELOPT_LINEMODE))
837 # endif
838 #endif
839                         {
840                                 init_termbuf();
841                                 tty_setecho(1);
842                                 set_termbuf();
843                         }
844                         changeok++;
845                         break;
846
847                 case TELOPT_BINARY:
848                         init_termbuf();
849                         tty_binaryout(1);
850                         set_termbuf();
851                         changeok++;
852                         break;
853
854                 case TELOPT_SGA:
855 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
856                         /*
857                          * If kludge linemode is in use, then we must
858                          * process an incoming do SGA for linemode
859                          * purposes.
860                          */
861                         if (lmodetype == KLUDGE_LINEMODE) {
862                                 /*
863                                  * Receipt of "do SGA" in kludge
864                                  * linemode is the peer asking us to
865                                  * turn off linemode.  Make note of
866                                  * the request.
867                                  */
868                                 clientstat(TELOPT_LINEMODE, WONT, 0);
869                                 /*
870                                  * If linemode did not get turned off
871                                  * then don't tell peer that we did.
872                                  * Breaking here forces a wont SGA to
873                                  * be returned.
874                                  */
875                                 if (linemode)
876                                         break;
877                         }
878 #else
879                         turn_on_sga = 0;
880 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
881                         changeok++;
882                         break;
883
884                 case TELOPT_STATUS:
885                         changeok++;
886                         break;
887
888                 case TELOPT_TM:
889                         /*
890                          * Special case for TM.  We send a WILL, but
891                          * pretend we sent a WONT.
892                          */
893                         send_will(option, 0);
894                         set_my_want_state_wont(option);
895                         set_my_state_wont(option);
896                         return;
897
898                 case TELOPT_LOGOUT:
899                         /*
900                          * When we get a LOGOUT option, respond
901                          * with a WILL LOGOUT, make sure that
902                          * it gets written out to the network,
903                          * and then just go away...
904                          */
905                         set_my_want_state_will(TELOPT_LOGOUT);
906                         send_will(TELOPT_LOGOUT, 0);
907                         set_my_state_will(TELOPT_LOGOUT);
908                         (void)netflush();
909                         cleanup(0);
910                         /* NOT REACHED */
911                         break;
912
913 #ifdef  ENCRYPTION
914                 case TELOPT_ENCRYPT:
915                         changeok++;
916                         break;
917 #endif  /* ENCRYPTION */
918                 case TELOPT_LINEMODE:
919                 case TELOPT_TTYPE:
920                 case TELOPT_NAWS:
921                 case TELOPT_TSPEED:
922                 case TELOPT_LFLOW:
923                 case TELOPT_XDISPLOC:
924 #ifdef  TELOPT_ENVIRON
925                 case TELOPT_NEW_ENVIRON:
926 #endif
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
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         output_data((const char *)wont, option);
954
955         DIAG(TD_OPTIONS, printoption("td: send wont", option));
956 }
957
958 void
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
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
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         static char terminalname[TERMINAL_TYPE_SIZE];
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         terminaltype = terminalname;
1146
1147         while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1148                                                                     !SB_EOF()) {
1149             int c;
1150
1151             c = SB_GET();
1152             if (isupper(c)) {
1153                 c = tolower(c);
1154             }
1155             *terminaltype++ = c;    /* accumulate name */
1156         }
1157         *terminaltype = 0;
1158         terminaltype = terminalname;
1159         break;
1160     }  /* end of case TELOPT_TTYPE */
1161
1162     case TELOPT_NAWS: {
1163         int xwinsize, ywinsize;
1164
1165         if (his_state_is_wont(TELOPT_NAWS))     /* Ignore if option disabled */
1166                 break;
1167
1168         if (SB_EOF())
1169                 return;
1170         xwinsize = SB_GET() << 8;
1171         if (SB_EOF())
1172                 return;
1173         xwinsize |= SB_GET();
1174         if (SB_EOF())
1175                 return;
1176         ywinsize = SB_GET() << 8;
1177         if (SB_EOF())
1178                 return;
1179         ywinsize |= SB_GET();
1180         clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1181
1182         break;
1183
1184     }  /* end of case TELOPT_NAWS */
1185
1186 #ifdef  LINEMODE
1187     case TELOPT_LINEMODE: {
1188         int request;
1189
1190         if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1191                 break;
1192         /*
1193          * Process linemode suboptions.
1194          */
1195         if (SB_EOF())
1196             break;              /* garbage was sent */
1197         request = SB_GET();     /* get will/wont */
1198
1199         if (SB_EOF())
1200             break;              /* another garbage check */
1201
1202         if (request == LM_SLC) {  /* SLC is not preceeded by WILL or WONT */
1203                 /*
1204                  * Process suboption buffer of slc's
1205                  */
1206                 start_slc(1);
1207                 do_opt_slc(subpointer, subend - subpointer);
1208                 (void) end_slc(0);
1209                 break;
1210         } else if (request == LM_MODE) {
1211                 if (SB_EOF())
1212                     return;
1213                 useeditmode = SB_GET();  /* get mode flag */
1214                 clientstat(LM_MODE, 0, 0);
1215                 break;
1216         }
1217
1218         if (SB_EOF())
1219             break;
1220         switch (SB_GET()) {  /* what suboption? */
1221         case LM_FORWARDMASK:
1222                 /*
1223                  * According to spec, only server can send request for
1224                  * forwardmask, and client can only return a positive response.
1225                  * So don't worry about it.
1226                  */
1227
1228         default:
1229                 break;
1230         }
1231         break;
1232     }  /* end of case TELOPT_LINEMODE */
1233 #endif
1234     case TELOPT_STATUS: {
1235         int mode;
1236
1237         if (SB_EOF())
1238             break;
1239         mode = SB_GET();
1240         switch (mode) {
1241         case TELQUAL_SEND:
1242             if (my_state_is_will(TELOPT_STATUS))
1243                 send_status();
1244             break;
1245
1246         case TELQUAL_IS:
1247             break;
1248
1249         default:
1250             break;
1251         }
1252         break;
1253     }  /* end of case TELOPT_STATUS */
1254
1255     case TELOPT_XDISPLOC: {
1256         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1257                 return;
1258         settimer(xdisplocsubopt);
1259         subpointer[SB_LEN()] = '\0';
1260         if (setenv("DISPLAY", (char *)subpointer, 1) == -1)
1261                 syslog(LOG_ERR, "setenv: cannot set DISPLAY=%s: %m", (char *)subpointer);
1262         break;
1263     }  /* end of case TELOPT_XDISPLOC */
1264
1265 #ifdef  TELOPT_NEW_ENVIRON
1266     case TELOPT_NEW_ENVIRON:
1267 #endif
1268     case TELOPT_OLD_ENVIRON: {
1269         int c;
1270         char *cp, *varp, *valp;
1271
1272         if (SB_EOF())
1273                 return;
1274         c = SB_GET();
1275         if (c == TELQUAL_IS) {
1276                 if (subchar == TELOPT_OLD_ENVIRON)
1277                         settimer(oenvironsubopt);
1278                 else
1279                         settimer(environsubopt);
1280         } else if (c != TELQUAL_INFO) {
1281                 return;
1282         }
1283
1284 #ifdef  TELOPT_NEW_ENVIRON
1285         if (subchar == TELOPT_NEW_ENVIRON) {
1286             while (!SB_EOF()) {
1287                 c = SB_GET();
1288                 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1289                         break;
1290             }
1291         } else
1292 #endif
1293         {
1294 #ifdef  ENV_HACK
1295             /*
1296              * We only want to do this if we haven't already decided
1297              * whether or not the other side has its VALUE and VAR
1298              * reversed.
1299              */
1300             if (env_ovar < 0) {
1301                 int last = -1;          /* invalid value */
1302                 int empty = 0;
1303                 int got_var = 0, got_value = 0, got_uservar = 0;
1304
1305                 /*
1306                  * The other side might have its VALUE and VAR values
1307                  * reversed.  To be interoperable, we need to determine
1308                  * which way it is.  If the first recognized character
1309                  * is a VAR or VALUE, then that will tell us what
1310                  * type of client it is.  If the fist recognized
1311                  * character is a USERVAR, then we continue scanning
1312                  * the suboption looking for two consecutive
1313                  * VAR or VALUE fields.  We should not get two
1314                  * consecutive VALUE fields, so finding two
1315                  * consecutive VALUE or VAR fields will tell us
1316                  * what the client is.
1317                  */
1318                 SB_SAVE();
1319                 while (!SB_EOF()) {
1320                         c = SB_GET();
1321                         switch(c) {
1322                         case OLD_ENV_VAR:
1323                                 if (last < 0 || last == OLD_ENV_VAR
1324                                     || (empty && (last == OLD_ENV_VALUE)))
1325                                         goto env_ovar_ok;
1326                                 got_var++;
1327                                 last = OLD_ENV_VAR;
1328                                 break;
1329                         case OLD_ENV_VALUE:
1330                                 if (last < 0 || last == OLD_ENV_VALUE
1331                                     || (empty && (last == OLD_ENV_VAR)))
1332                                         goto env_ovar_wrong;
1333                                 got_value++;
1334                                 last = OLD_ENV_VALUE;
1335                                 break;
1336                         case ENV_USERVAR:
1337                                 /* count strings of USERVAR as one */
1338                                 if (last != ENV_USERVAR)
1339                                         got_uservar++;
1340                                 if (empty) {
1341                                         if (last == OLD_ENV_VALUE)
1342                                                 goto env_ovar_ok;
1343                                         if (last == OLD_ENV_VAR)
1344                                                 goto env_ovar_wrong;
1345                                 }
1346                                 last = ENV_USERVAR;
1347                                 break;
1348                         case ENV_ESC:
1349                                 if (!SB_EOF())
1350                                         c = SB_GET();
1351                                 /* FALL THROUGH */
1352                         default:
1353                                 empty = 0;
1354                                 continue;
1355                         }
1356                         empty = 1;
1357                 }
1358                 if (empty) {
1359                         if (last == OLD_ENV_VALUE)
1360                                 goto env_ovar_ok;
1361                         if (last == OLD_ENV_VAR)
1362                                 goto env_ovar_wrong;
1363                 }
1364                 /*
1365                  * Ok, the first thing was a USERVAR, and there
1366                  * are not two consecutive VAR or VALUE commands,
1367                  * and none of the VAR or VALUE commands are empty.
1368                  * If the client has sent us a well-formed option,
1369                  * then the number of VALUEs received should always
1370                  * be less than or equal to the number of VARs and
1371                  * USERVARs received.
1372                  *
1373                  * If we got exactly as many VALUEs as VARs and
1374                  * USERVARs, the client has the same definitions.
1375                  *
1376                  * If we got exactly as many VARs as VALUEs and
1377                  * USERVARS, the client has reversed definitions.
1378                  */
1379                 if (got_uservar + got_var == got_value) {
1380             env_ovar_ok:
1381                         env_ovar = OLD_ENV_VAR;
1382                         env_ovalue = OLD_ENV_VALUE;
1383                 } else if (got_uservar + got_value == got_var) {
1384             env_ovar_wrong:
1385                         env_ovar = OLD_ENV_VALUE;
1386                         env_ovalue = OLD_ENV_VAR;
1387                         DIAG(TD_OPTIONS,
1388                             output_data("ENVIRON VALUE and VAR are reversed!\r\n"));
1389
1390                 }
1391             }
1392             SB_RESTORE();
1393 #endif
1394
1395             while (!SB_EOF()) {
1396                 c = SB_GET();
1397                 if ((c == env_ovar) || (c == ENV_USERVAR))
1398                         break;
1399             }
1400         }
1401
1402         if (SB_EOF())
1403                 return;
1404
1405         cp = varp = (char *)subpointer;
1406         valp = 0;
1407
1408         while (!SB_EOF()) {
1409                 c = SB_GET();
1410                 if (subchar == TELOPT_OLD_ENVIRON) {
1411                         if (c == env_ovar)
1412                                 c = NEW_ENV_VAR;
1413                         else if (c == env_ovalue)
1414                                 c = NEW_ENV_VALUE;
1415                 }
1416                 switch (c) {
1417
1418                 case NEW_ENV_VALUE:
1419                         *cp = '\0';
1420                         cp = valp = (char *)subpointer;
1421                         break;
1422
1423                 case NEW_ENV_VAR:
1424                 case ENV_USERVAR:
1425                         *cp = '\0';
1426                         if (envvarok(varp)) {
1427                                 if (valp) {
1428                                         if (setenv(varp, valp, 1) == -1)
1429                                                 syslog(LOG_ERR, "setenv: cannot set %s=%s: %m", varp, valp);
1430                                 }
1431                                 else
1432                                         unsetenv(varp);
1433                         }
1434                         cp = varp = (char *)subpointer;
1435                         valp = 0;
1436                         break;
1437
1438                 case ENV_ESC:
1439                         if (SB_EOF())
1440                                 break;
1441                         c = SB_GET();
1442                         /* FALL THROUGH */
1443                 default:
1444                         *cp++ = c;
1445                         break;
1446                 }
1447         }
1448         *cp = '\0';
1449         if (envvarok(varp)) {
1450                 if (valp) {
1451                         if (setenv(varp, valp, 1) == -1)
1452                                 syslog(LOG_ERR, "setenv: cannot set %s=%s: %m", varp, valp);
1453                 }
1454                 else
1455                         unsetenv(varp);
1456         }
1457         break;
1458     }  /* end of case TELOPT_NEW_ENVIRON */
1459 #ifdef  AUTHENTICATION
1460     case TELOPT_AUTHENTICATION:
1461         if (SB_EOF())
1462                 break;
1463         switch(SB_GET()) {
1464         case TELQUAL_SEND:
1465         case TELQUAL_REPLY:
1466                 /*
1467                  * These are sent by us and cannot be sent by
1468                  * the client.
1469                  */
1470                 break;
1471         case TELQUAL_IS:
1472                 auth_is(subpointer, SB_LEN());
1473                 break;
1474         case TELQUAL_NAME:
1475                 auth_name(subpointer, SB_LEN());
1476                 break;
1477         }
1478         break;
1479 #endif
1480 #ifdef  ENCRYPTION
1481     case TELOPT_ENCRYPT:
1482         if (SB_EOF())
1483                 break;
1484         switch(SB_GET()) {
1485         case ENCRYPT_SUPPORT:
1486                 encrypt_support(subpointer, SB_LEN());
1487                 break;
1488         case ENCRYPT_IS:
1489                 encrypt_is(subpointer, SB_LEN());
1490                 break;
1491         case ENCRYPT_REPLY:
1492                 encrypt_reply(subpointer, SB_LEN());
1493                 break;
1494         case ENCRYPT_START:
1495                 encrypt_start(subpointer, SB_LEN());
1496                 break;
1497         case ENCRYPT_END:
1498                 encrypt_end();
1499                 break;
1500         case ENCRYPT_REQSTART:
1501                 encrypt_request_start(subpointer, SB_LEN());
1502                 break;
1503         case ENCRYPT_REQEND:
1504                 /*
1505                  * We can always send an REQEND so that we cannot
1506                  * get stuck encrypting.  We should only get this
1507                  * if we have been able to get in the correct mode
1508                  * anyhow.
1509                  */
1510                 encrypt_request_end();
1511                 break;
1512         case ENCRYPT_ENC_KEYID:
1513                 encrypt_enc_keyid(subpointer, SB_LEN());
1514                 break;
1515         case ENCRYPT_DEC_KEYID:
1516                 encrypt_dec_keyid(subpointer, SB_LEN());
1517                 break;
1518         default:
1519                 break;
1520         }
1521         break;
1522 #endif  /* ENCRYPTION */
1523
1524     default:
1525         break;
1526     }  /* end of switch */
1527
1528 }  /* end of suboption */
1529
1530 static void
1531 doclientstat(void)
1532 {
1533         clientstat(TELOPT_LINEMODE, WILL, 0);
1534 }
1535
1536 #define ADD(c)   *ncp++ = c
1537 #define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1538 void
1539 send_status(void)
1540 {
1541         unsigned char statusbuf[256];
1542         unsigned char *ncp;
1543         unsigned char i;
1544
1545         ncp = statusbuf;
1546
1547         netflush();     /* get rid of anything waiting to go out */
1548
1549         ADD(IAC);
1550         ADD(SB);
1551         ADD(TELOPT_STATUS);
1552         ADD(TELQUAL_IS);
1553
1554         /*
1555          * We check the want_state rather than the current state,
1556          * because if we received a DO/WILL for an option that we
1557          * don't support, and the other side didn't send a DONT/WONT
1558          * in response to our WONT/DONT, then the "state" will be
1559          * WILL/DO, and the "want_state" will be WONT/DONT.  We
1560          * need to go by the latter.
1561          */
1562         for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1563                 if (my_want_state_is_will(i)) {
1564                         ADD(WILL);
1565                         ADD_DATA(i);
1566                         if (i == IAC)
1567                                 ADD(IAC);
1568                 }
1569                 if (his_want_state_is_will(i)) {
1570                         ADD(DO);
1571                         ADD_DATA(i);
1572                         if (i == IAC)
1573                                 ADD(IAC);
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         output_datalen(statusbuf, ncp - statusbuf);
1626         netflush();     /* Send it on its way */
1627
1628         DIAG(TD_OPTIONS,
1629                 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1630 }
1631
1632 /*
1633  * This function appends data to nfrontp and advances nfrontp.
1634  * Returns the number of characters written altogether (the
1635  * buffer may have been flushed in the process).
1636  */
1637
1638 int
1639 output_data(const char *format, ...)
1640 {
1641         va_list args;
1642         int len;
1643         char *buf;
1644
1645         va_start(args, format);
1646         if ((len = vasprintf(&buf, format, args)) == -1)
1647                 return -1;
1648         output_datalen(buf, len);
1649         va_end(args);
1650         free(buf);
1651         return (len);
1652 }
1653
1654 void
1655 output_datalen(const char *buf, int len)
1656 {
1657         int remaining, copied;
1658         
1659         remaining = BUFSIZ - (nfrontp - netobuf);
1660         while (len > 0) {
1661                 /* Free up enough space if the room is too low*/
1662                 if ((len > BUFSIZ ? BUFSIZ : len) > remaining) {
1663                         netflush();
1664                         remaining = BUFSIZ - (nfrontp - netobuf);
1665                 }
1666
1667                 /* Copy out as much as will fit */
1668                 copied = remaining > len ? len : remaining;
1669                 memmove(nfrontp, buf, copied);
1670                 nfrontp += copied;
1671                 len -= copied;
1672                 remaining -= copied;
1673                 buf += copied;
1674         }
1675         return;
1676 }