xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.bin/telnet/telnet.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
1 /*
2  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 #pragma ident	"%Z%%M%	%I%	%E% SMI"
7 
8 /*
9  * Copyright (c) 1988, 1990, 1993
10  *	The Regents of the University of California.  All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. All advertising materials mentioning features or use of this software
21  *    must display the following acknowledgement:
22  *	This product includes software developed by the University of
23  *	California, Berkeley and its contributors.
24  * 4. Neither the name of the University nor the names of its contributors
25  *    may be used to endorse or promote products derived from this software
26  *    without specific prior written permission.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38  * SUCH DAMAGE.
39  */
40 
41 #ifndef lint
42 static char sccsid[] = "@(#)telnet.c	8.1 (Berkeley) 6/6/93";
43 #endif /* not lint */
44 
45 #include <netdb.h>
46 #include <sys/types.h>
47 
48 #include <curses.h>
49 #include <signal.h>
50 /*
51  * By the way, we need to include curses.h before telnet.h since,
52  * among other things, telnet.h #defines 'DO', which is a variable
53  * declared in curses.h.
54  */
55 
56 #include <arpa/telnet.h>
57 
58 #include <ctype.h>
59 
60 #include "ring.h"
61 
62 #include "defines.h"
63 #include "externs.h"
64 #include "types.h"
65 #include "general.h"
66 
67 #include "auth.h"
68 #include "encrypt.h"
69 
70 #define	strip(x)	((x)&0x7f)
71 
72 /* Buffer for sub-options */
73 static unsigned char	subbuffer[SUBBUFSIZE];
74 static unsigned char	*subpointer;
75 static unsigned char	*subend;
76 
77 #define	SB_CLEAR()	subpointer = subbuffer;
78 #define	SB_TERM()	{ subend = subpointer; SB_CLEAR(); }
79 #define	SB_ACCUM(c)	if (subpointer < (subbuffer+sizeof (subbuffer))) { \
80 				*subpointer++ = (c); \
81 			}
82 
83 #define	SB_GET()	((*subpointer++)&0xff)
84 #define	SB_PEEK()	((*subpointer)&0xff)
85 #define	SB_EOF()	(subpointer >= subend)
86 #define	SB_LEN()	(subend - subpointer)
87 
88 char	options[SUBBUFSIZE];		/* The combined options */
89 char	do_dont_resp[SUBBUFSIZE];
90 char	will_wont_resp[SUBBUFSIZE];
91 
92 int eight = 0;
93 int autologin = 0;	/* Autologin anyone? */
94 int skiprc = 0;
95 int connected;
96 int showoptions;
97 static int ISend;	/* trying to send network data in */
98 int debug = 0;
99 int crmod;
100 int netdata;		/* Print out network data flow */
101 int crlf;		/* Should '\r' be mapped to <CR><LF> (or <CR><NUL>)? */
102 int telnetport;
103 int SYNCHing;		/* we are in TELNET SYNCH mode */
104 int flushout;		/* flush output */
105 int autoflush = 0;	/* flush output when interrupting? */
106 int autosynch;		/* send interrupt characters with SYNCH? */
107 int localflow;		/* we handle flow control locally */
108 int restartany;		/* if flow control enabled, restart on any character */
109 int localchars;		/* we recognize interrupt/quit */
110 int donelclchars;	/* the user has set "localchars" */
111 int donebinarytoggle;	/* the user has put us in binary */
112 int dontlecho;		/* do we suppress local echoing right now? */
113 int eof_pending = 0;	/* we received a genuine EOF on input, send IAC-EOF */
114 int globalmode;
115 
116 /* spin while waiting for authentication */
117 boolean_t scheduler_lockout_tty = B_FALSE;
118 int encrypt_flag = 0;
119 int forwardable_flag = 0;
120 int forward_flag = 0;
121 boolean_t wantencryption = B_FALSE;
122 
123 char *prompt = 0;
124 
125 cc_t escape;
126 cc_t rlogin;
127 boolean_t escape_valid = B_TRUE;
128 #ifdef	KLUDGELINEMODE
129 cc_t echoc;
130 #endif
131 
132 /*
133  * Telnet receiver states for fsm
134  */
135 #define	TS_DATA		0
136 #define	TS_IAC		1
137 #define	TS_WILL		2
138 #define	TS_WONT		3
139 #define	TS_DO		4
140 #define	TS_DONT		5
141 #define	TS_CR		6
142 #define	TS_SB		7		/* sub-option collection */
143 #define	TS_SE		8		/* looking for sub-option end */
144 
145 static int	telrcv_state;
146 #ifdef	OLD_ENVIRON
147 static	unsigned char telopt_environ = TELOPT_NEW_ENVIRON;
148 #else
149 #define	telopt_environ	TELOPT_NEW_ENVIRON
150 #endif
151 
152 jmp_buf	toplevel = { 0 };
153 jmp_buf	peerdied;
154 
155 static int flushline;
156 int	linemode;
157 
158 int	reqd_linemode = 0; /* Set if either new or old line mode in */
159 			/* effect since before initial negotiations */
160 
161 #ifdef	KLUDGELINEMODE
162 int	kludgelinemode = 1;
163 #endif
164 
165 /*
166  * The following are some clocks used to decide how to interpret
167  * the relationship between various variables.
168  */
169 
170 Clocks clocks;
171 
172 #ifdef	notdef
173 Modelist modelist[] = {
174 	{ "telnet command mode", COMMAND_LINE },
175 	{ "character-at-a-time mode", 0 },
176 	{ "character-at-a-time mode (local echo)", LOCAL_ECHO|LOCAL_CHARS },
177 	{ "line-by-line mode (remote echo)", LINE | LOCAL_CHARS },
178 	{ "line-by-line mode", LINE | LOCAL_ECHO | LOCAL_CHARS },
179 	{ "line-by-line mode (local echoing suppressed)", LINE | LOCAL_CHARS },
180 	{ "3270 mode", 0 },
181 };
182 #endif
183 
184 static void willoption(int);
185 static void wontoption(int);
186 static void lm_will(unsigned char *, int);
187 static void lm_wont(unsigned char *, int);
188 static void lm_do(unsigned char *, int);
189 static void lm_dont(unsigned char *, int);
190 static void slc_init(void);
191 static void slc_import(int);
192 static void slc_export(void);
193 static void slc_start_reply(size_t);
194 static void slc_add_reply(unsigned char, unsigned char, cc_t);
195 static void slc_end_reply(void);
196 static void slc(unsigned char *, int);
197 static int slc_update(void);
198 static void env_opt(unsigned char *, int);
199 static void env_opt_start(void);
200 static void sendeof(void);
201 static int is_unique(register char *, register char **, register char **);
202 
203 /*
204  * Initialize telnet environment.
205  */
206 
207 int
208 init_telnet()
209 {
210 	if (env_init() == 0)
211 		return (0);
212 
213 	SB_CLEAR();
214 	ClearArray(options);
215 
216 	connected = ISend = localflow = donebinarytoggle = 0;
217 	restartany = -1;
218 
219 	SYNCHing = 0;
220 
221 	/* Don't change NetTrace */
222 
223 	escape = CONTROL(']');
224 	rlogin = _POSIX_VDISABLE;
225 #ifdef	KLUDGELINEMODE
226 	echoc = CONTROL('E');
227 #endif
228 
229 	flushline = 1;
230 	telrcv_state = TS_DATA;
231 
232 	return (1);
233 }
234 
235 
236 #ifdef	notdef
237 #include <varargs.h>
238 
239 /*VARARGS*/
240 static void
241 printring(va_alist)
242 	va_dcl
243 {
244 	va_list ap;
245 	char buffer[100];		/* where things go */
246 	char *ptr;
247 	char *format;
248 	char *string;
249 	Ring *ring;
250 	int i;
251 
252 	va_start(ap);
253 
254 	ring = va_arg(ap, Ring *);
255 	format = va_arg(ap, char *);
256 	ptr = buffer;
257 
258 	while ((i = *format++) != 0) {
259 		if (i == '%') {
260 			i = *format++;
261 			switch (i) {
262 			case 'c':
263 				*ptr++ = va_arg(ap, int);
264 				break;
265 			case 's':
266 				string = va_arg(ap, char *);
267 				ring_supply_data(ring, buffer, ptr-buffer);
268 				ring_supply_data(ring, string, strlen(string));
269 				ptr = buffer;
270 				break;
271 			case 0:
272 				ExitString("printring: trailing %%.\n",
273 				    EXIT_FAILURE);
274 				/*NOTREACHED*/
275 			default:
276 				ExitString("printring: unknown format "
277 				    "character.\n", EXIT_FAILURE);
278 				/*NOTREACHED*/
279 			}
280 		} else {
281 			*ptr++ = i;
282 		}
283 	}
284 	ring_supply_data(ring, buffer, ptr-buffer);
285 }
286 #endif
287 
288 /*
289  * These routines are in charge of sending option negotiations
290  * to the other side.
291  *
292  * The basic idea is that we send the negotiation if either side
293  * is in disagreement as to what the current state should be.
294  */
295 
296 void
297 send_do(c, init)
298 	register int c, init;
299 {
300 	if (init) {
301 		if (((do_dont_resp[c] == 0) && my_state_is_do(c)) ||
302 		    my_want_state_is_do(c))
303 			return;
304 		set_my_want_state_do(c);
305 		do_dont_resp[c]++;
306 	}
307 	NET2ADD(IAC, DO);
308 	NETADD(c);
309 	printoption("SENT", DO, c);
310 }
311 
312 void
313 send_dont(c, init)
314 	register int c, init;
315 {
316 	if (init) {
317 		if (((do_dont_resp[c] == 0) && my_state_is_dont(c)) ||
318 		    my_want_state_is_dont(c))
319 			return;
320 		set_my_want_state_dont(c);
321 		do_dont_resp[c]++;
322 	}
323 	NET2ADD(IAC, DONT);
324 	NETADD(c);
325 	printoption("SENT", DONT, c);
326 }
327 
328 void
329 send_will(c, init)
330 	register int c, init;
331 {
332 	if (init) {
333 		if (((will_wont_resp[c] == 0) && my_state_is_will(c)) ||
334 		    my_want_state_is_will(c))
335 			return;
336 		set_my_want_state_will(c);
337 		will_wont_resp[c]++;
338 	}
339 	NET2ADD(IAC, WILL);
340 	NETADD(c);
341 	printoption("SENT", WILL, c);
342 }
343 
344 void
345 send_wont(c, init)
346 	register int c, init;
347 {
348 	if (init) {
349 		if (((will_wont_resp[c] == 0) && my_state_is_wont(c)) ||
350 		    my_want_state_is_wont(c))
351 			return;
352 		set_my_want_state_wont(c);
353 		will_wont_resp[c]++;
354 	}
355 	NET2ADD(IAC, WONT);
356 	NETADD(c);
357 	printoption("SENT", WONT, c);
358 }
359 
360 
361 static void
362 willoption(option)
363 	int option;
364 {
365 	int new_state_ok = 0;
366 
367 	if (do_dont_resp[option]) {
368 	    --do_dont_resp[option];
369 	    if (do_dont_resp[option] && my_state_is_do(option))
370 		--do_dont_resp[option];
371 	}
372 
373 	if ((do_dont_resp[option] == 0) && my_want_state_is_dont(option)) {
374 
375 	    switch (option) {
376 
377 	    case TELOPT_ECHO:
378 	    case TELOPT_SGA:
379 		if (reqd_linemode && my_state_is_dont(option)) {
380 		    break;
381 		}
382 		/* FALLTHROUGH */
383 	    case TELOPT_BINARY:
384 		settimer(modenegotiated);
385 		/* FALLTHROUGH */
386 	    case TELOPT_STATUS:
387 	    case TELOPT_AUTHENTICATION:
388 		/* FALLTHROUGH */
389 	    case TELOPT_ENCRYPT:
390 		new_state_ok = 1;
391 		break;
392 
393 	    case TELOPT_TM:
394 		if (flushout)
395 		    flushout = 0;
396 		/*
397 		 * Special case for TM.  If we get back a WILL,
398 		 * pretend we got back a WONT.
399 		 */
400 		set_my_want_state_dont(option);
401 		set_my_state_dont(option);
402 		return;			/* Never reply to TM will's/wont's */
403 
404 	    case TELOPT_LINEMODE:
405 	    default:
406 		break;
407 	    }
408 
409 	    if (new_state_ok) {
410 		set_my_want_state_do(option);
411 		send_do(option, 0);
412 		setconnmode(0);		/* possibly set new tty mode */
413 	    } else {
414 		do_dont_resp[option]++;
415 		send_dont(option, 0);
416 	    }
417 	}
418 	set_my_state_do(option);
419 	if (option == TELOPT_ENCRYPT)
420 		encrypt_send_support();
421 }
422 
423 static void
424 wontoption(option)
425 	int option;
426 {
427 	if (do_dont_resp[option]) {
428 		--do_dont_resp[option];
429 		if (do_dont_resp[option] && my_state_is_dont(option))
430 			--do_dont_resp[option];
431 	}
432 
433 	if ((do_dont_resp[option] == 0) && my_want_state_is_do(option)) {
434 
435 		switch (option) {
436 
437 #ifdef	KLUDGELINEMODE
438 		case TELOPT_SGA:
439 			if (!kludgelinemode)
440 				break;
441 			/* FALLTHROUGH */
442 #endif
443 		case TELOPT_ECHO:
444 			settimer(modenegotiated);
445 			break;
446 
447 		case TELOPT_TM:
448 			if (flushout)
449 				flushout = 0;
450 			set_my_want_state_dont(option);
451 			set_my_state_dont(option);
452 			return;		/* Never reply to TM will's/wont's */
453 
454 		default:
455 			break;
456 		}
457 		set_my_want_state_dont(option);
458 		if (my_state_is_do(option))
459 			send_dont(option, 0);
460 		setconnmode(0);			/* Set new tty mode */
461 	} else if (option == TELOPT_TM) {
462 		/*
463 		 * Special case for TM.
464 		 */
465 		if (flushout)
466 			flushout = 0;
467 		set_my_want_state_dont(option);
468 	}
469 	set_my_state_dont(option);
470 }
471 
472 static void
473 dooption(option)
474 	int option;
475 {
476 	int new_state_ok = 0;
477 
478 	if (will_wont_resp[option]) {
479 		--will_wont_resp[option];
480 		if (will_wont_resp[option] && my_state_is_will(option))
481 			--will_wont_resp[option];
482 	}
483 
484 	if (will_wont_resp[option] == 0) {
485 		if (my_want_state_is_wont(option)) {
486 
487 			switch (option) {
488 
489 			case TELOPT_TM:
490 				/*
491 				 * Special case for TM.  We send a WILL,
492 				 * but pretend we sent WONT.
493 				 */
494 				send_will(option, 0);
495 				set_my_want_state_wont(TELOPT_TM);
496 				set_my_state_wont(TELOPT_TM);
497 				return;
498 
499 			case TELOPT_BINARY:	/* binary mode */
500 			case TELOPT_NAWS:	/* window size */
501 			case TELOPT_TSPEED:	/* terminal speed */
502 			case TELOPT_LFLOW:	/* local flow control */
503 			case TELOPT_TTYPE:	/* terminal type option */
504 			case TELOPT_SGA:	/* no big deal */
505 			case TELOPT_ENCRYPT:	/* encryption variable option */
506 				new_state_ok = 1;
507 				break;
508 
509 			case TELOPT_NEW_ENVIRON:
510 				/* New environment variable option */
511 #ifdef	OLD_ENVIRON
512 				if (my_state_is_will(TELOPT_OLD_ENVIRON))
513 					/* turn off the old */
514 					send_wont(TELOPT_OLD_ENVIRON, 1);
515 goto env_common;
516 			case TELOPT_OLD_ENVIRON:
517 				/* Old environment variable option */
518 				if (my_state_is_will(TELOPT_NEW_ENVIRON))
519 					/* Don't enable if new one is in use! */
520 					break;
521 env_common:
522 				telopt_environ = option;
523 #endif
524 				new_state_ok = 1;
525 				break;
526 
527 			case TELOPT_AUTHENTICATION:
528 				if (autologin)
529 					new_state_ok = 1;
530 				break;
531 
532 			case TELOPT_XDISPLOC:	/* X Display location */
533 				if (env_getvalue((unsigned char *)"DISPLAY"))
534 					new_state_ok = 1;
535 				break;
536 
537 			case TELOPT_LINEMODE:
538 #ifdef	KLUDGELINEMODE
539 				kludgelinemode = 0;
540 				send_do(TELOPT_SGA, 1);
541 #endif
542 				set_my_want_state_will(TELOPT_LINEMODE);
543 				send_will(option, 0);
544 				set_my_state_will(TELOPT_LINEMODE);
545 				slc_init();
546 				return;
547 
548 			case TELOPT_ECHO: /* We're never going to echo... */
549 			default:
550 				break;
551 			}
552 
553 			if (new_state_ok) {
554 				set_my_want_state_will(option);
555 				send_will(option, 0);
556 				setconnmode(0);		/* Set new tty mode */
557 			} else {
558 				will_wont_resp[option]++;
559 				send_wont(option, 0);
560 			}
561 		} else {
562 			/*
563 			 * Handle options that need more things done after the
564 			 * other side has acknowledged the option.
565 			 */
566 			switch (option) {
567 			case TELOPT_LINEMODE:
568 #ifdef	KLUDGELINEMODE
569 				kludgelinemode = 0;
570 				send_do(TELOPT_SGA, 1);
571 #endif
572 				set_my_state_will(option);
573 				slc_init();
574 				send_do(TELOPT_SGA, 0);
575 				return;
576 			}
577 		}
578 	}
579 	set_my_state_will(option);
580 }
581 
582 	static void
583 dontoption(option)
584 	int option;
585 {
586 
587 	if (will_wont_resp[option]) {
588 	    --will_wont_resp[option];
589 	    if (will_wont_resp[option] && my_state_is_wont(option))
590 		--will_wont_resp[option];
591 	}
592 
593 	if ((will_wont_resp[option] == 0) && my_want_state_is_will(option)) {
594 	    switch (option) {
595 	    case TELOPT_LINEMODE:
596 		linemode = 0;	/* put us back to the default state */
597 		break;
598 #ifdef	OLD_ENVIRON
599 	    case TELOPT_NEW_ENVIRON:
600 		/*
601 		 * The new environ option wasn't recognized, try
602 		 * the old one.
603 		 */
604 		send_will(TELOPT_OLD_ENVIRON, 1);
605 		telopt_environ = TELOPT_OLD_ENVIRON;
606 		break;
607 #endif
608 	    }
609 	    /* we always accept a DONT */
610 	    set_my_want_state_wont(option);
611 	    if (my_state_is_will(option))
612 		send_wont(option, 0);
613 	    setconnmode(0);			/* Set new tty mode */
614 	}
615 	set_my_state_wont(option);
616 }
617 
618 /*
619  * Given a buffer returned by tgetent(), this routine will turn
620  * the pipe seperated list of names in the buffer into an array
621  * of pointers to null terminated names.  We toss out any bad,
622  * duplicate, or verbose names (names with spaces).
623  */
624 
625 static char *name_unknown = "UNKNOWN";
626 static char *unknown[] = { 0, 0 };
627 
628 static char **
629 mklist(buf, name)
630 	char *buf, *name;
631 {
632 	register int n;
633 	register char c, *cp, **argvp, *cp2, **argv, **avt;
634 
635 	if (name) {
636 		if (strlen(name) > 40u) {
637 			name = 0;
638 			unknown[0] = name_unknown;
639 		} else {
640 			unknown[0] = name;
641 			upcase(name);
642 		}
643 	} else
644 		unknown[0] = name_unknown;
645 	/*
646 	 * Count up the number of names.
647 	 */
648 	for (n = 1, cp = buf; *cp && *cp != ':'; cp++) {
649 		if (*cp == '|')
650 			n++;
651 	}
652 	/*
653 	 * Allocate an array to put the name pointers into
654 	 */
655 	argv = malloc((n+3)*sizeof (char *));
656 	if (argv == 0)
657 		return (unknown);
658 
659 	/*
660 	 * Fill up the array of pointers to names.
661 	 */
662 	*argv = 0;
663 	argvp = argv+1;
664 	n = 0;
665 	for (cp = cp2 = buf; (c = *cp) != NULL;  cp++) {
666 		if (c == '|' || c == ':') {
667 			*cp++ = '\0';
668 			/*
669 			 * Skip entries that have spaces or are over 40
670 			 * characters long.  If this is our environment
671 			 * name, then put it up front.  Otherwise, as
672 			 * long as this is not a duplicate name (case
673 			 * insensitive) add it to the list.
674 			 */
675 			if (n || (cp - cp2 > 41))
676 				/* EMPTY */;
677 			else if (name && (strncasecmp(name, cp2, cp-cp2) == 0))
678 				*argv = cp2;
679 			else if (is_unique(cp2, argv+1, argvp))
680 				*argvp++ = cp2;
681 			if (c == ':')
682 				break;
683 			/*
684 			 * Skip multiple delimiters. Reset cp2 to
685 			 * the beginning of the next name. Reset n,
686 			 * the flag for names with spaces.
687 			 */
688 			while ((c = *cp) == '|')
689 				cp++;
690 			cp2 = cp;
691 			n = 0;
692 		}
693 		/*
694 		 * Skip entries with spaces or non-ascii values.
695 		 * Convert lower case letters to upper case.
696 		 */
697 		if ((c == ' ') || !isascii(c))
698 			n = 1;
699 		else if (islower(c))
700 			*cp = toupper(c);
701 	}
702 
703 	/*
704 	 * Check for an old V6 2 character name.  If the second
705 	 * name points to the beginning of the buffer, and is
706 	 * only 2 characters long, move it to the end of the array.
707 	 */
708 	if ((argv[1] == buf) && (strlen(argv[1]) == 2)) {
709 		--argvp;
710 		for (avt = &argv[1]; avt < argvp; avt++)
711 			*avt = *(avt+1);
712 		*argvp++ = buf;
713 	}
714 
715 	/*
716 	 * Duplicate last name, for TTYPE option, and null
717 	 * terminate the array.  If we didn't find a match on
718 	 * our terminal name, put that name at the beginning.
719 	 */
720 	cp = *(argvp-1);
721 	*argvp++ = cp;
722 	*argvp = 0;
723 
724 	if (*argv == 0) {
725 		if (name)
726 			*argv = name;
727 		else {
728 			--argvp;
729 			for (avt = argv; avt < argvp; avt++)
730 				*avt = *(avt+1);
731 		}
732 	}
733 	if (*argv)
734 		return (argv);
735 	else
736 		return (unknown);
737 }
738 
739 static int
740 is_unique(name, as, ae)
741 	register char *name, **as, **ae;
742 {
743 	register char **ap;
744 	register int n;
745 
746 	n = strlen(name) + 1;
747 	for (ap = as; ap < ae; ap++)
748 		if (strncasecmp(*ap, name, n) == 0)
749 			return (0);
750 	return (1);
751 }
752 
753 #define	termbuf	ttytype
754 extern char ttytype[];
755 
756 int resettermname = 1;
757 
758 static char *
759 gettermname(void)
760 {
761 	char *tname;
762 	static char **tnamep = 0;
763 	static char **next;
764 	int err;
765 
766 	if (resettermname) {
767 		resettermname = 0;
768 		if (tnamep && tnamep != unknown)
769 			free(tnamep);
770 		tname = (char *)env_getvalue((unsigned char *)"TERM");
771 		if ((tname != NULL) && (setupterm(tname, 1, &err) == 0)) {
772 			tnamep = mklist(termbuf, tname);
773 		} else {
774 			if (tname && (strlen(tname) <= 40u)) {
775 				unknown[0] = tname;
776 				upcase(tname);
777 			} else
778 				unknown[0] = name_unknown;
779 			tnamep = unknown;
780 		}
781 		next = tnamep;
782 	}
783 	if (*next == 0)
784 		next = tnamep;
785 	return (*next++);
786 }
787 /*
788  * suboption()
789  *
790  *	Look at the sub-option buffer, and try to be helpful to the other
791  * side.
792  *
793  *	Currently we recognize:
794  *
795  *		Terminal type, send request.
796  *		Terminal speed (send request).
797  *		Local flow control (is request).
798  *		Linemode
799  */
800 
801     static void
802 suboption()
803 {
804 	unsigned char subchar;
805 
806 	printsub('<', subbuffer, SB_LEN()+2);
807 	switch (subchar = SB_GET()) {
808 	case TELOPT_TTYPE:
809 		if (my_want_state_is_wont(TELOPT_TTYPE))
810 			return;
811 		if (SB_EOF() || SB_GET() != TELQUAL_SEND) {
812 			return;
813 		} else {
814 			char *name;
815 			unsigned char temp[50];
816 			int len, bytes;
817 
818 			name = gettermname();
819 			len = strlen(name) + 4 + 2;
820 			bytes = snprintf((char *)temp, sizeof (temp),
821 				"%c%c%c%c%s%c%c", IAC, SB,
822 				TELOPT_TTYPE, TELQUAL_IS, name, IAC, SE);
823 			if ((len < NETROOM()) && (bytes < sizeof (temp))) {
824 					ring_supply_data(&netoring, temp, len);
825 					printsub('>', &temp[2], len-2);
826 			} else {
827 				ExitString("No room in buffer for "
828 				    "terminal type.\n", EXIT_FAILURE);
829 				/*NOTREACHED*/
830 			}
831 		}
832 		break;
833 	case TELOPT_TSPEED:
834 		if (my_want_state_is_wont(TELOPT_TSPEED))
835 			return;
836 		if (SB_EOF())
837 			return;
838 		if (SB_GET() == TELQUAL_SEND) {
839 			int ospeed, ispeed;
840 			unsigned char temp[50];
841 			int len, bytes;
842 
843 			TerminalSpeeds(&ispeed, &ospeed);
844 
845 			bytes = snprintf((char *)temp, sizeof (temp),
846 			    "%c%c%c%c%d,%d%c%c", IAC, SB,
847 			    TELOPT_TSPEED, TELQUAL_IS, ospeed, ispeed, IAC, SE);
848 			len = strlen((char *)temp+4) + 4; /* temp[3] is 0 ... */
849 
850 			if ((len < NETROOM()) && (bytes < sizeof (temp))) {
851 				ring_supply_data(&netoring, temp, len);
852 				printsub('>', temp+2, len - 2);
853 			}
854 			else
855 				(void) printf(
856 				    "telnet: not enough room in buffer "
857 				    "for terminal speed option reply\n");
858 		}
859 		break;
860 	case TELOPT_LFLOW:
861 		if (my_want_state_is_wont(TELOPT_LFLOW))
862 			return;
863 		if (SB_EOF())
864 			return;
865 		switch (SB_GET()) {
866 		case LFLOW_RESTART_ANY:
867 			restartany = 1;
868 			break;
869 		case LFLOW_RESTART_XON:
870 			restartany = 0;
871 			break;
872 		case LFLOW_ON:
873 			localflow = 1;
874 			break;
875 		case LFLOW_OFF:
876 			localflow = 0;
877 			break;
878 		default:
879 			return;
880 		}
881 		setcommandmode();
882 		setconnmode(0);
883 		break;
884 
885 	case TELOPT_LINEMODE:
886 		if (my_want_state_is_wont(TELOPT_LINEMODE))
887 			return;
888 		if (SB_EOF())
889 			return;
890 		switch (SB_GET()) {
891 		case WILL:
892 			lm_will(subpointer, SB_LEN());
893 			break;
894 		case WONT:
895 			lm_wont(subpointer, SB_LEN());
896 			break;
897 		case DO:
898 			lm_do(subpointer, SB_LEN());
899 			break;
900 		case DONT:
901 			lm_dont(subpointer, SB_LEN());
902 			break;
903 		case LM_SLC:
904 			slc(subpointer, SB_LEN());
905 			break;
906 		case LM_MODE:
907 			lm_mode(subpointer, SB_LEN(), 0);
908 			break;
909 		default:
910 			break;
911 		}
912 		break;
913 
914 #ifdef	OLD_ENVIRON
915 	case TELOPT_OLD_ENVIRON:
916 #endif
917 	case TELOPT_NEW_ENVIRON:
918 		if (SB_EOF())
919 			return;
920 		switch (SB_PEEK()) {
921 		case TELQUAL_IS:
922 		case TELQUAL_INFO:
923 			if (my_want_state_is_dont(subchar))
924 				return;
925 			break;
926 		case TELQUAL_SEND:
927 			if (my_want_state_is_wont(subchar)) {
928 				return;
929 			}
930 			break;
931 		default:
932 			return;
933 		}
934 		env_opt(subpointer, SB_LEN());
935 		break;
936 
937 	case TELOPT_XDISPLOC:
938 		if (my_want_state_is_wont(TELOPT_XDISPLOC))
939 			return;
940 		if (SB_EOF())
941 			return;
942 		if (SB_GET() == TELQUAL_SEND) {
943 			unsigned char temp[50], *dp;
944 			int len, bytes;
945 
946 			if ((dp = env_getvalue((unsigned char *)"DISPLAY")) ==
947 			    NULL) {
948 				/*
949 				 * Something happened, we no longer have a
950 				 * DISPLAY variable.  So, turn off the option.
951 				 */
952 				send_wont(TELOPT_XDISPLOC, 1);
953 				break;
954 			}
955 			bytes = snprintf((char *)temp, sizeof (temp),
956 			    "%c%c%c%c%s%c%c", IAC, SB,
957 			    TELOPT_XDISPLOC, TELQUAL_IS, dp, IAC, SE);
958 			len = strlen((char *)temp+4) + 4; /* temp[3] is 0 ... */
959 
960 			if ((len < NETROOM()) && (bytes < sizeof (temp))) {
961 				ring_supply_data(&netoring, temp, len);
962 				printsub('>', temp+2, len - 2);
963 			}
964 			else
965 				(void) printf(
966 				    "telnet: not enough room in buffer"
967 				    " for display location option reply\n");
968 		}
969 		break;
970 
971 	case TELOPT_AUTHENTICATION: {
972 		if (!autologin)
973 			break;
974 		if (SB_EOF())
975 			return;
976 		switch (SB_GET()) {
977 		case TELQUAL_SEND:
978 			if (my_want_state_is_wont(TELOPT_AUTHENTICATION))
979 				return;
980 			auth_send(subpointer, SB_LEN());
981 			break;
982 		case TELQUAL_REPLY:
983 			if (my_want_state_is_wont(TELOPT_AUTHENTICATION))
984 				return;
985 			auth_reply(subpointer, SB_LEN());
986 			break;
987 		}
988 	}
989 	break;
990 
991 	case TELOPT_ENCRYPT:
992 		if (SB_EOF())
993 			return;
994 		switch (SB_GET()) {
995 		case ENCRYPT_START:
996 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
997 				return;
998 			encrypt_start(subpointer, SB_LEN());
999 			break;
1000 		case ENCRYPT_END:
1001 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
1002 				return;
1003 			encrypt_end();
1004 			break;
1005 		case ENCRYPT_SUPPORT:
1006 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1007 				return;
1008 			encrypt_support(subpointer, SB_LEN());
1009 			break;
1010 		case ENCRYPT_REQSTART:
1011 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1012 				return;
1013 			encrypt_request_start(subpointer, SB_LEN());
1014 			break;
1015 		case ENCRYPT_REQEND:
1016 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1017 				return;
1018 			/*
1019 			 * We can always send an REQEND so that we cannot
1020 			 * get stuck encrypting.  We should only get this
1021 			 * if we have been able to get in the correct mode
1022 			 * anyhow.
1023 			 */
1024 			encrypt_request_end();
1025 			break;
1026 		case ENCRYPT_IS:
1027 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
1028 				return;
1029 			encrypt_is(subpointer, SB_LEN());
1030 			break;
1031 		case ENCRYPT_REPLY:
1032 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1033 				return;
1034 			encrypt_reply(subpointer, SB_LEN());
1035 			break;
1036 		case ENCRYPT_ENC_KEYID:
1037 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
1038 				return;
1039 			encrypt_enc_keyid(subpointer, SB_LEN());
1040 			break;
1041 		case ENCRYPT_DEC_KEYID:
1042 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1043 				return;
1044 			encrypt_dec_keyid(subpointer, SB_LEN());
1045 			break;
1046 		default:
1047 			break;
1048 		}
1049 		break;
1050 	default:
1051 		break;
1052 	}
1053 }
1054 
1055 static unsigned char str_lm[] = { IAC, SB, TELOPT_LINEMODE, 0, 0, IAC, SE };
1056 
1057 static void
1058 lm_will(cmd, len)
1059 	unsigned char *cmd;
1060 	int len;
1061 {
1062 	if (len < 1) {
1063 		/* Should not happen... */
1064 		(void) printf(
1065 		    "telnet: command missing from linemode WILL request\n");
1066 		return;
1067 	}
1068 	switch (cmd[0]) {
1069 	case LM_FORWARDMASK:	/* We shouldn't ever get this... */
1070 	default:
1071 		str_lm[3] = DONT;
1072 		str_lm[4] = cmd[0];
1073 		if (NETROOM() > sizeof (str_lm)) {
1074 			ring_supply_data(&netoring, str_lm, sizeof (str_lm));
1075 			printsub('>', &str_lm[2], sizeof (str_lm)-2);
1076 		}
1077 		else
1078 			(void) printf("telnet: not enough room in buffer for"
1079 			    "reply to linemode WILL request\n");
1080 		break;
1081 	}
1082 }
1083 
1084 static void
1085 lm_wont(cmd, len)
1086 	unsigned char *cmd;
1087 	int len;
1088 {
1089 	if (len < 1) {
1090 		/* Should not happen... */
1091 		(void) printf(
1092 		    "telnet: command missing from linemode WONT request\n");
1093 		return;
1094 	}
1095 	switch (cmd[0]) {
1096 	case LM_FORWARDMASK:	/* We shouldn't ever get this... */
1097 	default:
1098 		/* We are always DONT, so don't respond */
1099 		return;
1100 	}
1101 }
1102 
1103 static void
1104 lm_do(cmd, len)
1105 	unsigned char *cmd;
1106 	int len;
1107 {
1108 	if (len < 1) {
1109 		/* Should not happen... */
1110 		(void) printf(
1111 		    "telnet: command missing from linemode DO request\n");
1112 		return;
1113 	}
1114 	switch (cmd[0]) {
1115 	case LM_FORWARDMASK:
1116 	default:
1117 		str_lm[3] = WONT;
1118 		str_lm[4] = cmd[0];
1119 		if (NETROOM() > sizeof (str_lm)) {
1120 			ring_supply_data(&netoring, str_lm, sizeof (str_lm));
1121 			printsub('>', &str_lm[2], sizeof (str_lm)-2);
1122 		}
1123 		else
1124 			(void) printf("telnet: not enough room in buffer for"
1125 			    "reply to linemode DO request\n");
1126 		break;
1127 	}
1128 }
1129 
1130 static void
1131 lm_dont(cmd, len)
1132 	unsigned char *cmd;
1133 	int len;
1134 {
1135 	if (len < 1) {
1136 		/* Should not happen... */
1137 		(void) printf(
1138 		    "telnet: command missing from linemode DONT request\n");
1139 		return;
1140 	}
1141 	switch (cmd[0]) {
1142 	case LM_FORWARDMASK:
1143 	default:
1144 		/* we are always WONT, so don't respond */
1145 		break;
1146 	}
1147 }
1148 
1149 static unsigned char str_lm_mode[] = {
1150 	IAC, SB, TELOPT_LINEMODE, LM_MODE, 0, IAC, SE
1151 };
1152 
1153 	void
1154 lm_mode(cmd, len, init)
1155 	unsigned char *cmd;
1156 	int len, init;
1157 {
1158 	if (len != 1)
1159 		return;
1160 	if ((linemode&MODE_MASK&~MODE_ACK) == *cmd)
1161 		return;
1162 	linemode = *cmd&(MODE_MASK&~MODE_ACK);
1163 	str_lm_mode[4] = linemode;
1164 	if (!init)
1165 		str_lm_mode[4] |= MODE_ACK;
1166 	if (NETROOM() > sizeof (str_lm_mode)) {
1167 		ring_supply_data(&netoring, str_lm_mode, sizeof (str_lm_mode));
1168 		printsub('>', &str_lm_mode[2], sizeof (str_lm_mode)-2);
1169 	}
1170 	else
1171 		(void) printf("telnet: not enough room in buffer for"
1172 		    "reply to linemode request\n");
1173 	setconnmode(0);	/* set changed mode */
1174 }
1175 
1176 
1177 
1178 /*
1179  * slc()
1180  * Handle special character suboption of LINEMODE.
1181  */
1182 
1183 static struct spc {
1184 	cc_t val;
1185 	cc_t *valp;
1186 	char flags;	/* Current flags & level */
1187 	char mylevel;	/* Maximum level & flags */
1188 } spc_data[NSLC+1];
1189 
1190 #define	SLC_IMPORT	0
1191 #define	SLC_EXPORT	1
1192 #define	SLC_RVALUE	2
1193 static int slc_mode = SLC_EXPORT;
1194 
1195 static void
1196 slc_init()
1197 {
1198 	register struct spc *spcp;
1199 
1200 	localchars = 1;
1201 	for (spcp = spc_data; spcp < &spc_data[NSLC+1]; spcp++) {
1202 		spcp->val = 0;
1203 		spcp->valp = 0;
1204 		spcp->flags = spcp->mylevel = SLC_NOSUPPORT;
1205 	}
1206 
1207 #define	initfunc(func, flags) { \
1208 				spcp = &spc_data[func]; \
1209 				if (spcp->valp = tcval(func)) { \
1210 				    spcp->val = *spcp->valp; \
1211 				    spcp->mylevel = SLC_VARIABLE|(flags);\
1212 				} else { \
1213 				    spcp->val = 0; \
1214 				    spcp->mylevel = SLC_DEFAULT; \
1215 				} \
1216 			    }
1217 
1218 	initfunc(SLC_SYNCH, 0);
1219 	/* No BRK */
1220 	initfunc(SLC_AO, 0);
1221 	initfunc(SLC_AYT, 0);
1222 	/* No EOR */
1223 	initfunc(SLC_ABORT, SLC_FLUSHIN|SLC_FLUSHOUT);
1224 	initfunc(SLC_EOF, 0);
1225 	initfunc(SLC_SUSP, SLC_FLUSHIN);
1226 	initfunc(SLC_EC, 0);
1227 	initfunc(SLC_EL, 0);
1228 	initfunc(SLC_EW, 0);
1229 	initfunc(SLC_RP, 0);
1230 	initfunc(SLC_LNEXT, 0);
1231 	initfunc(SLC_XON, 0);
1232 	initfunc(SLC_XOFF, 0);
1233 	initfunc(SLC_FORW1, 0);
1234 #ifdef	USE_TERMIO
1235 	initfunc(SLC_FORW2, 0);
1236 	/* No FORW2 */
1237 #endif
1238 
1239 	initfunc(SLC_IP, SLC_FLUSHIN|SLC_FLUSHOUT);
1240 #undef	initfunc
1241 
1242 	if (slc_mode == SLC_EXPORT)
1243 		slc_export();
1244 	else
1245 		slc_import(1);
1246 
1247 }
1248 
1249 void
1250 slcstate()
1251 {
1252 	(void) printf("Special characters are %s values\n",
1253 		slc_mode == SLC_IMPORT ? "remote default" :
1254 		slc_mode == SLC_EXPORT ? "local" :
1255 					"remote");
1256 }
1257 
1258 void
1259 slc_mode_export()
1260 {
1261 	slc_mode = SLC_EXPORT;
1262 	if (my_state_is_will(TELOPT_LINEMODE))
1263 		slc_export();
1264 }
1265 
1266 void
1267 slc_mode_import(def)
1268     int def;
1269 {
1270     slc_mode = def ? SLC_IMPORT : SLC_RVALUE;
1271     if (my_state_is_will(TELOPT_LINEMODE))
1272 	slc_import(def);
1273 }
1274 
1275 static unsigned char slc_import_val[] = {
1276 	IAC, SB, TELOPT_LINEMODE, LM_SLC, 0, SLC_VARIABLE, 0, IAC, SE
1277 };
1278 static unsigned char slc_import_def[] = {
1279 	IAC, SB, TELOPT_LINEMODE, LM_SLC, 0, SLC_DEFAULT, 0, IAC, SE
1280 };
1281 
1282 static void
1283 slc_import(def)
1284 	int def;
1285 {
1286 	if (NETROOM() > sizeof (slc_import_val)) {
1287 		if (def) {
1288 			ring_supply_data(&netoring, slc_import_def,
1289 			    sizeof (slc_import_def));
1290 			printsub('>', &slc_import_def[2],
1291 			    sizeof (slc_import_def)-2);
1292 		} else {
1293 			ring_supply_data(&netoring, slc_import_val,
1294 			    sizeof (slc_import_val));
1295 			printsub('>', &slc_import_val[2],
1296 			    sizeof (slc_import_val)-2);
1297 		}
1298 	}
1299 	else
1300 		(void) printf(
1301 		    "telnet: not enough room in buffer for slc import"
1302 		    " request\n");
1303 }
1304 
1305 static uchar_t *slc_reply = NULL;
1306 static uchar_t *slc_replyp = NULL;
1307 /*
1308  * The SLC reply consists of: IAC, SB, TELOPT_LINEMODE, LM_SLC,
1309  * SLC triplets[], IAC, SE. i.e. it has a 'wrapper' of 6 control characters.
1310  */
1311 #define	SLC_WRAPPER_SIZE 6
1312 
1313 static void
1314 slc_export()
1315 {
1316 	register struct spc *spcp;
1317 
1318 	TerminalDefaultChars();
1319 
1320 	slc_start_reply(NSLC * 3);	/* 3 bytes needed per triplet */
1321 	for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
1322 		if (spcp->mylevel != SLC_NOSUPPORT) {
1323 			if (spcp->val == (cc_t)(_POSIX_VDISABLE))
1324 				spcp->flags = SLC_NOSUPPORT;
1325 			else
1326 				spcp->flags = spcp->mylevel;
1327 			if (spcp->valp)
1328 				spcp->val = *spcp->valp;
1329 			slc_add_reply(spcp - spc_data, spcp->flags, spcp->val);
1330 		}
1331 	}
1332 	slc_end_reply();
1333 	(void) slc_update();
1334 	setconnmode(1);	/* Make sure the character values are set */
1335 }
1336 
1337 static void
1338 slc(cp, len)
1339 	register unsigned char *cp;
1340 	int len;
1341 {
1342 	register struct spc *spcp;
1343 	register int func, level;
1344 
1345 	slc_start_reply(len);
1346 
1347 	for (; len >= 3; len -= 3, cp += 3) {
1348 
1349 		func = cp[SLC_FUNC];
1350 
1351 		if (func == 0) {
1352 			/*
1353 			 * Client side: always ignore 0 function.
1354 			 */
1355 			continue;
1356 		}
1357 		if (func > NSLC) {
1358 			if ((cp[SLC_FLAGS] & SLC_LEVELBITS) != SLC_NOSUPPORT)
1359 				slc_add_reply(func, SLC_NOSUPPORT, 0);
1360 			continue;
1361 		}
1362 
1363 		spcp = &spc_data[func];
1364 
1365 		level = cp[SLC_FLAGS]&(SLC_LEVELBITS|SLC_ACK);
1366 
1367 		if ((cp[SLC_VALUE] == (unsigned char)spcp->val) &&
1368 		    ((level&SLC_LEVELBITS) == (spcp->flags&SLC_LEVELBITS))) {
1369 			continue;
1370 		}
1371 
1372 		if (level == (SLC_DEFAULT|SLC_ACK)) {
1373 			/*
1374 			 * This is an error condition, the SLC_ACK
1375 			 * bit should never be set for the SLC_DEFAULT
1376 			 * level.  Our best guess to recover is to
1377 			 * ignore the SLC_ACK bit.
1378 			 */
1379 			cp[SLC_FLAGS] &= ~SLC_ACK;
1380 		}
1381 
1382 		if (level == ((spcp->flags&SLC_LEVELBITS)|SLC_ACK)) {
1383 			spcp->val = (cc_t)cp[SLC_VALUE];
1384 			spcp->flags = cp[SLC_FLAGS];	/* include SLC_ACK */
1385 			continue;
1386 		}
1387 
1388 		level &= ~SLC_ACK;
1389 
1390 		if (level <= (spcp->mylevel&SLC_LEVELBITS)) {
1391 			spcp->flags = cp[SLC_FLAGS]|SLC_ACK;
1392 			spcp->val = (cc_t)cp[SLC_VALUE];
1393 		}
1394 		if (level == SLC_DEFAULT) {
1395 			if ((spcp->mylevel&SLC_LEVELBITS) != SLC_DEFAULT)
1396 				spcp->flags = spcp->mylevel;
1397 			else
1398 				spcp->flags = SLC_NOSUPPORT;
1399 		}
1400 		slc_add_reply(func, spcp->flags, spcp->val);
1401 	}
1402 	slc_end_reply();
1403 	if (slc_update())
1404 		setconnmode(1);	/* set the  new character values */
1405 }
1406 
1407 void
1408 slc_check()
1409 {
1410 	register struct spc *spcp;
1411 
1412 	slc_start_reply(NSLC * 3);	/* 3 bytes needed per triplet */
1413 	for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
1414 		if (spcp->valp && spcp->val != *spcp->valp) {
1415 			spcp->val = *spcp->valp;
1416 			if (spcp->val == (cc_t)(_POSIX_VDISABLE))
1417 				spcp->flags = SLC_NOSUPPORT;
1418 			else
1419 				spcp->flags = spcp->mylevel;
1420 			slc_add_reply(spcp - spc_data, spcp->flags, spcp->val);
1421 		}
1422 	}
1423 	slc_end_reply();
1424 	setconnmode(1);
1425 }
1426 
1427 static void
1428 slc_start_reply(size_t len)
1429 {
1430 	/*
1431 	 * SLC triplets may contain escaped characters, allow for
1432 	 * worst case by allocating 2 bytes for every character.
1433 	 */
1434 	slc_reply = realloc(slc_reply, (len * 2) + SLC_WRAPPER_SIZE);
1435 	if (slc_reply == NULL) {
1436 		fprintf(stderr, "telnet: error allocating SLC reply memory\n");
1437 		return;
1438 	}
1439 	slc_replyp = slc_reply;
1440 	*slc_replyp++ = IAC;
1441 	*slc_replyp++ = SB;
1442 	*slc_replyp++ = TELOPT_LINEMODE;
1443 	*slc_replyp++ = LM_SLC;
1444 }
1445 
1446 static void
1447 slc_add_reply(unsigned char func, unsigned char flags, cc_t value)
1448 {
1449 	if ((*slc_replyp++ = func) == IAC)
1450 		*slc_replyp++ = IAC;
1451 	if ((*slc_replyp++ = flags) == IAC)
1452 		*slc_replyp++ = IAC;
1453 	if ((*slc_replyp++ = (unsigned char)value) == IAC)
1454 		*slc_replyp++ = IAC;
1455 }
1456 
1457 static void
1458 slc_end_reply()
1459 {
1460 	register int len;
1461 
1462 	*slc_replyp++ = IAC;
1463 	*slc_replyp++ = SE;
1464 	len = slc_replyp - slc_reply;
1465 	if (len <= SLC_WRAPPER_SIZE)
1466 		return;
1467 	if (NETROOM() > len) {
1468 		ring_supply_data(&netoring, slc_reply, slc_replyp - slc_reply);
1469 		printsub('>', &slc_reply[2], slc_replyp - slc_reply - 2);
1470 	}
1471 	else
1472 		(void) printf("telnet: not enough room in buffer for slc end "
1473 		    "reply\n");
1474 }
1475 
1476 static int
1477 slc_update()
1478 {
1479 	register struct spc *spcp;
1480 	int need_update = 0;
1481 
1482 	for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
1483 		if (!(spcp->flags&SLC_ACK))
1484 			continue;
1485 		spcp->flags &= ~SLC_ACK;
1486 		if (spcp->valp && (*spcp->valp != spcp->val)) {
1487 			*spcp->valp = spcp->val;
1488 			need_update = 1;
1489 		}
1490 	}
1491 	return (need_update);
1492 }
1493 
1494 #ifdef	OLD_ENVIRON
1495 #ifdef	ENV_HACK
1496 /*
1497  * Earlier version of telnet/telnetd from the BSD code had
1498  * the definitions of VALUE and VAR reversed.  To ensure
1499  * maximum interoperability, we assume that the server is
1500  * an older BSD server, until proven otherwise.  The newer
1501  * BSD servers should be able to handle either definition,
1502  * so it is better to use the wrong values if we don't
1503  * know what type of server it is.
1504  */
1505 int env_auto = 1;
1506 int old_env_var = OLD_ENV_VAR;
1507 int old_env_value = OLD_ENV_VALUE;
1508 #else
1509 #define	old_env_var	OLD_ENV_VAR
1510 #define	old_env_value	OLD_ENV_VALUE
1511 #endif
1512 #endif
1513 
1514 static void
1515 env_opt(buf, len)
1516 	register unsigned char *buf;
1517 	register int len;
1518 {
1519 	register unsigned char *ep = 0, *epc = 0;
1520 	register int i;
1521 
1522 	switch (buf[0]&0xff) {
1523 	case TELQUAL_SEND:
1524 		env_opt_start();
1525 		if (len == 1) {
1526 			env_opt_add(NULL);
1527 		} else for (i = 1; i < len; i++) {
1528 			switch (buf[i]&0xff) {
1529 #ifdef	OLD_ENVIRON
1530 			case OLD_ENV_VAR:
1531 #ifdef	ENV_HACK
1532 				if (telopt_environ == TELOPT_OLD_ENVIRON &&
1533 				    env_auto) {
1534 					/* Server has the same definitions */
1535 					old_env_var = OLD_ENV_VAR;
1536 					old_env_value = OLD_ENV_VALUE;
1537 				}
1538 				/* FALLTHROUGH */
1539 #endif
1540 			case OLD_ENV_VALUE:
1541 				/*
1542 				 * Although OLD_ENV_VALUE is not legal, we will
1543 				 * still recognize it, just in case it is an
1544 				 * old server that has VAR & VALUE mixed up...
1545 				 */
1546 				/* FALLTHROUGH */
1547 #else
1548 			case NEW_ENV_VAR:
1549 #endif
1550 			case ENV_USERVAR:
1551 				if (ep) {
1552 					*epc = 0;
1553 					env_opt_add(ep);
1554 				}
1555 				ep = epc = &buf[i+1];
1556 				break;
1557 			case ENV_ESC:
1558 				i++;
1559 				/*FALLTHROUGH*/
1560 			default:
1561 				if (epc)
1562 					*epc++ = buf[i];
1563 				break;
1564 			}
1565 		}
1566 		if (ep) {
1567 			*epc = 0;
1568 			env_opt_add(ep);
1569 		}
1570 		env_opt_end(1);
1571 		break;
1572 
1573 	case TELQUAL_IS:
1574 	case TELQUAL_INFO:
1575 		/* Ignore for now.  We shouldn't get it anyway. */
1576 		break;
1577 
1578 	default:
1579 		break;
1580 	}
1581 }
1582 
1583 static unsigned char *opt_reply;
1584 static unsigned char *opt_replyp;
1585 static unsigned char *opt_replyend;
1586 #define	OPT_REPLY_INITIAL_SIZE	256
1587 /*
1588  * The opt reply consists of: IAC, SB, telopt_environ, TELQUAL_IS,
1589  * value, IAC, SE. i.e. it has a 'wrapper' of 6 control characters.
1590  */
1591 #define	OPT_WRAPPER_SIZE 6
1592 
1593 static void
1594 env_opt_start()
1595 {
1596 	opt_reply = realloc(opt_reply, OPT_REPLY_INITIAL_SIZE);
1597 	if (opt_reply == NULL) {
1598 		(void) printf(
1599 		    "telnet: error allocating environment option memory\n");
1600 		opt_reply = opt_replyp = opt_replyend = NULL;
1601 		return;
1602 	}
1603 	opt_replyp = opt_reply;
1604 	opt_replyend = opt_reply + OPT_REPLY_INITIAL_SIZE;
1605 	*opt_replyp++ = IAC;
1606 	*opt_replyp++ = SB;
1607 	*opt_replyp++ = telopt_environ;
1608 	*opt_replyp++ = TELQUAL_IS;
1609 }
1610 
1611 	void
1612 env_opt_start_info()
1613 {
1614 	env_opt_start();
1615 	if (opt_replyp)
1616 	    opt_replyp[-1] = TELQUAL_INFO;
1617 }
1618 
1619 	void
1620 env_opt_add(ep)
1621 	register unsigned char *ep;
1622 {
1623 	register unsigned char *vp, c;
1624 	int opt_reply_size;
1625 	int opt_reply_used;
1626 
1627 	if (opt_reply == NULL)		/* XXX */
1628 		return;			/* XXX */
1629 
1630 	if (ep == NULL || *ep == '\0') {
1631 		/* Send user defined variables first. */
1632 		(void) env_default(1, 0);
1633 		while (ep = env_default(0, 0))
1634 			env_opt_add(ep);
1635 
1636 		/* Now add the list of well know variables.  */
1637 		(void) env_default(1, 1);
1638 		while (ep = env_default(0, 1))
1639 			env_opt_add(ep);
1640 		return;
1641 	}
1642 	vp = env_getvalue(ep);
1643 
1644 	/*
1645 	 * Calculate space required for opt_reply and allocate more if required.
1646 	 * Assume worst case that every character is escaped, so needs 2 bytes.
1647 	 */
1648 	opt_reply_used = opt_replyp - opt_reply;	/* existing contents */
1649 	opt_reply_size = opt_reply_used + OPT_WRAPPER_SIZE +
1650 	    (2 * (strlen((char *)ep))) +
1651 	    (vp == NULL ? 0 : (2 * strlen((char *)vp)));
1652 
1653 	if (opt_reply_size > (opt_replyend - opt_reply)) {
1654 		opt_reply = realloc(opt_reply, opt_reply_size);
1655 		if (opt_reply == NULL) {
1656 			(void) printf(
1657 			    "telnet: can't allocate environment option "
1658 			    "reply\n");
1659 			opt_reply = opt_replyp = opt_replyend = NULL;
1660 			return;
1661 		}
1662 		opt_replyp = opt_reply + opt_reply_used;
1663 		opt_replyend = opt_reply + opt_reply_size;
1664 	}
1665 
1666 	if (opt_welldefined((char *)ep))
1667 #ifdef	OLD_ENVIRON
1668 		if (telopt_environ == TELOPT_OLD_ENVIRON)
1669 			*opt_replyp++ = old_env_var;
1670 		else
1671 #endif
1672 			*opt_replyp++ = NEW_ENV_VAR;
1673 	else
1674 		*opt_replyp++ = ENV_USERVAR;
1675 	for (;;) {
1676 		while ((c = *ep++) != NULL) {
1677 			switch (c&0xff) {
1678 			case IAC:
1679 				*opt_replyp++ = IAC;
1680 				break;
1681 			case NEW_ENV_VAR:
1682 			case NEW_ENV_VALUE:
1683 			case ENV_ESC:
1684 			case ENV_USERVAR:
1685 				*opt_replyp++ = ENV_ESC;
1686 				break;
1687 			}
1688 			*opt_replyp++ = c;
1689 		}
1690 		if ((ep = vp) != NULL) {
1691 #ifdef	OLD_ENVIRON
1692 			if (telopt_environ == TELOPT_OLD_ENVIRON)
1693 				*opt_replyp++ = old_env_value;
1694 			else
1695 #endif
1696 				*opt_replyp++ = NEW_ENV_VALUE;
1697 			vp = NULL;
1698 		} else
1699 			break;
1700 	}
1701 }
1702 
1703 	int
1704 opt_welldefined(ep)
1705 	char *ep;
1706 {
1707 	if ((strcmp(ep, "USER") == 0) ||
1708 	    (strcmp(ep, "DISPLAY") == 0) ||
1709 	    (strcmp(ep, "PRINTER") == 0) ||
1710 	    (strcmp(ep, "SYSTEMTYPE") == 0) ||
1711 	    (strcmp(ep, "JOB") == 0) ||
1712 	    (strcmp(ep, "ACCT") == 0))
1713 		return (1);
1714 	return (0);
1715 }
1716 	void
1717 env_opt_end(emptyok)
1718 	register int emptyok;
1719 {
1720 	register int len;
1721 
1722 	len = opt_replyp - opt_reply + 2;
1723 	if (emptyok || len > OPT_WRAPPER_SIZE) {
1724 		*opt_replyp++ = IAC;
1725 		*opt_replyp++ = SE;
1726 		if (NETROOM() > len) {
1727 			ring_supply_data(&netoring, opt_reply, len);
1728 			printsub('>', &opt_reply[2], len - 2);
1729 		}
1730 		else
1731 			(void) printf("telnet: not enough room in buffer for "
1732 			    "environment option end reply\n");
1733 	}
1734 	if (opt_reply) {
1735 		free(opt_reply);
1736 		opt_reply = opt_replyp = opt_replyend = NULL;
1737 	}
1738 }
1739 
1740 
1741 
1742 int
1743 telrcv()
1744 {
1745 	register int c;
1746 	register int scc;
1747 	register unsigned char *sbp;
1748 	int count;
1749 	int returnValue = 0;
1750 	int min_room = 0;
1751 
1752 	scc = 0;
1753 	count = 0;
1754 	while (--min_room > 2 || (min_room = TTYROOM()) > 2) {
1755 		if (scc == 0) {
1756 			if (count) {
1757 				ring_consumed(&netiring, count);
1758 				returnValue = 1;
1759 				count = 0;
1760 			}
1761 			sbp = netiring.consume;
1762 			scc = ring_full_consecutive(&netiring);
1763 			if (scc == 0) {
1764 				/* No more data coming in */
1765 				break;
1766 			}
1767 		}
1768 
1769 		c = *sbp++ & 0xff, scc--; count++;
1770 
1771 		if (decrypt_input)
1772 			c = (*decrypt_input)(c);
1773 
1774 		switch (telrcv_state) {
1775 
1776 		case TS_CR:
1777 			telrcv_state = TS_DATA;
1778 			if (c == '\0') {
1779 				break;	/* Ignore \0 after CR */
1780 			} else if ((c == '\n') &&
1781 			    my_want_state_is_dont(TELOPT_ECHO) && !crmod) {
1782 				TTYADD(c);
1783 				break;
1784 			}
1785 			/* FALLTHROUGH */
1786 
1787 		case TS_DATA:
1788 			if (c == IAC) {
1789 				telrcv_state = TS_IAC;
1790 				break;
1791 			}
1792 			/*
1793 			 * The 'crmod' hack (see following) is needed
1794 			 * since we can't * set CRMOD on output only.
1795 			 * Machines like MULTICS like to send \r without
1796 			 * \n; since we must turn off CRMOD to get proper
1797 			 * input, the mapping is done here (sigh).
1798 			 */
1799 			if ((c == '\r') &&
1800 			    my_want_state_is_dont(TELOPT_BINARY)) {
1801 				if (scc > 0) {
1802 					c = *sbp&0xff;
1803 
1804 					if (decrypt_input)
1805 						c = (*decrypt_input)(c);
1806 
1807 					if (c == 0) {
1808 						sbp++, scc--; count++;
1809 						/* a "true" CR */
1810 						TTYADD('\r');
1811 					} else if (my_want_state_is_dont(
1812 					    TELOPT_ECHO) && (c == '\n')) {
1813 						sbp++, scc--; count++;
1814 						TTYADD('\n');
1815 					} else {
1816 
1817 						if (decrypt_input)
1818 							(*decrypt_input)(-1);
1819 
1820 						TTYADD('\r');
1821 						if (crmod) {
1822 							TTYADD('\n');
1823 						}
1824 					}
1825 				} else {
1826 					telrcv_state = TS_CR;
1827 					TTYADD('\r');
1828 					if (crmod) {
1829 						TTYADD('\n');
1830 					}
1831 				}
1832 			} else {
1833 				TTYADD(c);
1834 			}
1835 			continue;
1836 
1837 		case TS_IAC:
1838 process_iac:
1839 			switch (c) {
1840 
1841 			case WILL:
1842 				telrcv_state = TS_WILL;
1843 				continue;
1844 
1845 			case WONT:
1846 				telrcv_state = TS_WONT;
1847 				continue;
1848 
1849 			case DO:
1850 				telrcv_state = TS_DO;
1851 				continue;
1852 
1853 			case DONT:
1854 				telrcv_state = TS_DONT;
1855 				continue;
1856 
1857 			case DM:
1858 				/*
1859 				 * We may have missed an urgent notification,
1860 				 * so make sure we flush whatever is in the
1861 				 * buffer currently.
1862 				 */
1863 				printoption("RCVD", IAC, DM);
1864 				SYNCHing = 1;
1865 				if (ttyflush(1) == -2) {
1866 					/* This will not return. */
1867 					fatal_tty_error("write");
1868 				}
1869 				SYNCHing = stilloob();
1870 				settimer(gotDM);
1871 				break;
1872 
1873 			case SB:
1874 				SB_CLEAR();
1875 				telrcv_state = TS_SB;
1876 				continue;
1877 
1878 			case IAC:
1879 				TTYADD(IAC);
1880 				break;
1881 
1882 			case NOP:
1883 			case GA:
1884 			default:
1885 				printoption("RCVD", IAC, c);
1886 				break;
1887 			}
1888 			telrcv_state = TS_DATA;
1889 			continue;
1890 
1891 		case TS_WILL:
1892 			printoption("RCVD", WILL, c);
1893 			willoption(c);
1894 			telrcv_state = TS_DATA;
1895 			continue;
1896 
1897 		case TS_WONT:
1898 			printoption("RCVD", WONT, c);
1899 			wontoption(c);
1900 			telrcv_state = TS_DATA;
1901 			continue;
1902 
1903 		case TS_DO:
1904 			printoption("RCVD", DO, c);
1905 			dooption(c);
1906 			if (c == TELOPT_NAWS) {
1907 				sendnaws();
1908 			} else if (c == TELOPT_LFLOW) {
1909 				localflow = 1;
1910 				setcommandmode();
1911 				setconnmode(0);
1912 			}
1913 			telrcv_state = TS_DATA;
1914 			continue;
1915 
1916 		case TS_DONT:
1917 			printoption("RCVD", DONT, c);
1918 			dontoption(c);
1919 			flushline = 1;
1920 			setconnmode(0);	/* set new tty mode (maybe) */
1921 			telrcv_state = TS_DATA;
1922 			continue;
1923 
1924 		case TS_SB:
1925 			if (c == IAC) {
1926 				telrcv_state = TS_SE;
1927 			} else {
1928 				SB_ACCUM(c);
1929 			}
1930 			continue;
1931 
1932 		case TS_SE:
1933 			if (c != SE) {
1934 				if (c != IAC) {
1935 			/*
1936 			 * This is an error.  We only expect to get
1937 			 * "IAC IAC" or "IAC SE".  Several things may
1938 			 * have happend.  An IAC was not doubled, the
1939 			 * IAC SE was left off, or another option got
1940 			 * inserted into the suboption are all possibilities.
1941 			 * If we assume that the IAC was not doubled,
1942 			 * and really the IAC SE was left off, we could
1943 			 * get into an infinate loop here.  So, instead,
1944 			 * we terminate the suboption, and process the
1945 			 * partial suboption if we can.
1946 			 */
1947 					SB_ACCUM(IAC);
1948 					SB_ACCUM(c);
1949 					subpointer -= 2;
1950 					SB_TERM();
1951 
1952 					printoption("In SUBOPTION processing, "
1953 					    "RCVD", IAC, c);
1954 					suboption();	/* handle sub-option */
1955 					telrcv_state = TS_IAC;
1956 					goto process_iac;
1957 				}
1958 				SB_ACCUM(c);
1959 				telrcv_state = TS_SB;
1960 			} else {
1961 				SB_ACCUM(IAC);
1962 				SB_ACCUM(SE);
1963 				subpointer -= 2;
1964 				SB_TERM();
1965 				suboption();	/* handle sub-option */
1966 				telrcv_state = TS_DATA;
1967 			}
1968 		}
1969 	}
1970 	if (count)
1971 		ring_consumed(&netiring, count);
1972 	return (returnValue||count);
1973 }
1974 
1975 static int bol = 1, local = 0;
1976 
1977 int
1978 rlogin_susp()
1979 {
1980 	if (local) {
1981 		local = 0;
1982 		bol = 1;
1983 		command(0, "z\n", 2);
1984 		return (1);
1985 	}
1986 	return (0);
1987 }
1988 
1989 static int
1990 telsnd()
1991 {
1992 	int tcc;
1993 	int count;
1994 	int returnValue = 0;
1995 	unsigned char *tbp;
1996 
1997 	tcc = 0;
1998 	count = 0;
1999 	while (NETROOM() > 2) {
2000 		register int sc;
2001 		register int c;
2002 
2003 		if (tcc == 0) {
2004 			if (count) {
2005 				ring_consumed(&ttyiring, count);
2006 				returnValue = 1;
2007 				count = 0;
2008 			}
2009 			tbp = ttyiring.consume;
2010 			tcc = ring_full_consecutive(&ttyiring);
2011 			if (tcc == 0) {
2012 				break;
2013 			}
2014 		}
2015 		c = *tbp++ & 0xff, sc = strip(c), tcc--; count++;
2016 		if (rlogin != _POSIX_VDISABLE) {
2017 			if (bol) {
2018 				bol = 0;
2019 				if (sc == rlogin) {
2020 					local = 1;
2021 					continue;
2022 				}
2023 			} else if (local) {
2024 				local = 0;
2025 				if (sc == '.' || c == termEofChar) {
2026 					bol = 1;
2027 					command(0, "close\n", 6);
2028 					continue;
2029 				}
2030 				if (sc == termSuspChar) {
2031 					bol = 1;
2032 					command(0, "z\n", 2);
2033 					continue;
2034 				}
2035 				if (sc == escape) {
2036 					command(0, (char *)tbp, tcc);
2037 					bol = 1;
2038 					count += tcc;
2039 					tcc = 0;
2040 					flushline = 1;
2041 					break;
2042 				}
2043 				if (sc != rlogin) {
2044 					++tcc;
2045 					--tbp;
2046 					--count;
2047 					c = sc = rlogin;
2048 				}
2049 			}
2050 			if ((sc == '\n') || (sc == '\r'))
2051 				bol = 1;
2052 		} else if (sc == escape && escape_valid) {
2053 			/*
2054 			 * Double escape is a pass through of a single
2055 			 * escape character.
2056 			 */
2057 			if (tcc && strip(*tbp) == escape) {
2058 				tbp++;
2059 				tcc--;
2060 				count++;
2061 				bol = 0;
2062 			} else {
2063 				command(0, (char *)tbp, tcc);
2064 				bol = 1;
2065 				count += tcc;
2066 				tcc = 0;
2067 				flushline = 1;
2068 				break;
2069 			}
2070 		} else
2071 			bol = 0;
2072 #ifdef	KLUDGELINEMODE
2073 		if (kludgelinemode && (globalmode&MODE_EDIT) && (sc == echoc)) {
2074 			if (tcc > 0 && strip(*tbp) == echoc) {
2075 				tcc--; tbp++; count++;
2076 			} else {
2077 				dontlecho = !dontlecho;
2078 				settimer(echotoggle);
2079 				setconnmode(0);
2080 				flushline = 1;
2081 				break;
2082 			}
2083 		}
2084 #endif
2085 		if (MODE_LOCAL_CHARS(globalmode)) {
2086 			if (TerminalSpecialChars(sc) == 0) {
2087 				bol = 1;
2088 				break;
2089 			}
2090 		}
2091 		if (my_want_state_is_wont(TELOPT_BINARY)) {
2092 			switch (c) {
2093 			case '\n':
2094 				/*
2095 				 * If we are in CRMOD mode (\r ==> \n)
2096 				 * on our local machine, then probably
2097 				 * a newline (unix) is CRLF (TELNET).
2098 				 */
2099 				if (MODE_LOCAL_CHARS(globalmode)) {
2100 					NETADD('\r');
2101 				}
2102 				NETADD('\n');
2103 				bol = flushline = 1;
2104 				break;
2105 			case '\r':
2106 				if (!crlf) {
2107 					NET2ADD('\r', '\0');
2108 				} else {
2109 					NET2ADD('\r', '\n');
2110 				}
2111 				bol = flushline = 1;
2112 				break;
2113 			case IAC:
2114 				NET2ADD(IAC, IAC);
2115 				break;
2116 			default:
2117 				NETADD(c);
2118 				break;
2119 			}
2120 		} else if (c == IAC) {
2121 			NET2ADD(IAC, IAC);
2122 		} else {
2123 			NETADD(c);
2124 		}
2125 	}
2126 	if (count)
2127 		ring_consumed(&ttyiring, count);
2128 	return (returnValue||count);	/* Non-zero if we did anything */
2129 }
2130 
2131 /*
2132  * Scheduler()
2133  *
2134  * Try to do something.
2135  *
2136  * If we do something useful, return 1; else return 0.
2137  *
2138  */
2139 
2140 
2141 int
2142 Scheduler(block)
2143 	int	block;		/* should we block in the select ? */
2144 {
2145 	/*
2146 	 * One wants to be a bit careful about setting returnValue
2147 	 * to one, since a one implies we did some useful work,
2148 	 * and therefore probably won't be called to block next
2149 	 * time (TN3270 mode only).
2150 	 */
2151 	int returnValue;
2152 	int netin, netout, netex, ttyin, ttyout;
2153 
2154 	/* Decide which rings should be processed */
2155 
2156 	netout = ring_full_count(&netoring) &&
2157 	    (flushline ||
2158 	    (my_want_state_is_wont(TELOPT_LINEMODE)
2159 #ifdef	KLUDGELINEMODE
2160 	    /* X */ && (!kludgelinemode || my_want_state_is_do(TELOPT_SGA))
2161 #endif
2162 	    /* XXX */) ||
2163 	    my_want_state_is_will(TELOPT_BINARY));
2164 	ttyout = ring_full_count(&ttyoring);
2165 
2166 	ttyin = (ring_empty_count(&ttyiring) && !eof_pending);
2167 
2168 	netin = !ISend && ring_empty_count(&netiring);
2169 
2170 	netex = !SYNCHing;
2171 
2172 	if (scheduler_lockout_tty) {
2173 		ttyin = ttyout = 0;
2174 	}
2175 
2176 	/* Call to system code to process rings */
2177 
2178 	returnValue = process_rings(netin, netout, netex, ttyin, ttyout,
2179 	    !block);
2180 
2181 	/* Now, look at the input rings, looking for work to do. */
2182 
2183 	if (ring_full_count(&ttyiring)) {
2184 		returnValue |= telsnd();
2185 	} else {
2186 		/*
2187 		 * If ttyiring is empty, check to see if there is a real EOF
2188 		 * pending.  If so, we can maybe do the EOF write now.
2189 		 */
2190 		if (eof_pending) {
2191 			eof_pending = 0;
2192 			sendeof();
2193 		}
2194 	}
2195 
2196 	if (ring_full_count(&netiring)) {
2197 		returnValue |= telrcv();
2198 	}
2199 	return (returnValue);
2200 }
2201 
2202 /*
2203  * Select from tty and network...
2204  */
2205 void
2206 telnet(user)
2207 	char *user;
2208 {
2209 	sys_telnet_init();
2210 
2211 	{
2212 		static char local_host[MAXHOSTNAMELEN] = { 0 };
2213 
2214 		if (!local_host[0]) {
2215 			(void) gethostname(local_host, sizeof (local_host));
2216 			local_host[sizeof (local_host)-1] = 0;
2217 		}
2218 		auth_encrypt_init(local_host, hostname, "TELNET");
2219 		auth_encrypt_user(user);
2220 	}
2221 
2222 	if (autologin)
2223 		send_will(TELOPT_AUTHENTICATION, 1);
2224 
2225 	if (telnetport || wantencryption) {
2226 		send_do(TELOPT_ENCRYPT, 1);
2227 		send_will(TELOPT_ENCRYPT, 1);
2228 	}
2229 
2230 	if (telnetport) {
2231 		if (!reqd_linemode)
2232 		    send_do(TELOPT_SGA, 1);
2233 		send_will(TELOPT_TTYPE, 1);
2234 		send_will(TELOPT_NAWS, 1);
2235 		send_will(TELOPT_TSPEED, 1);
2236 		send_will(TELOPT_LFLOW, 1);
2237 		if (!reqd_linemode)
2238 		    send_will(TELOPT_LINEMODE, 1);
2239 		send_will(TELOPT_NEW_ENVIRON, 1);
2240 		send_do(TELOPT_STATUS, 1);
2241 		if (env_getvalue((unsigned char *)"DISPLAY"))
2242 			send_will(TELOPT_XDISPLOC, 1);
2243 		if (eight)
2244 			tel_enter_binary(eight);
2245 	}
2246 
2247 	/*
2248 	 * Note: we assume a tie to the authentication option here.  This
2249 	 * is necessary so that authentication fails, we don't spin
2250 	 * forever.
2251 	 */
2252 	if (wantencryption) {
2253 		boolean_t printed_encrypt = B_FALSE;
2254 		extern boolean_t auth_has_failed;
2255 		time_t timeout = time(0) + 60;
2256 
2257 		send_do(TELOPT_ENCRYPT, 1);
2258 		send_will(TELOPT_ENCRYPT, 1);
2259 		for (;;) {
2260 		    if (my_want_state_is_wont(TELOPT_AUTHENTICATION)) {
2261 			(void) printf(gettext(
2262 				"\nServer refused to negotiate "
2263 				"authentication, which is required\n"
2264 				"for encryption.  Good-bye.\n\r"));
2265 			Exit(EXIT_FAILURE);
2266 		    }
2267 		    if (auth_has_failed) {
2268 			(void) printf(gettext(
2269 			    "\nAuthentication negotation has failed, "
2270 			    "which is required for\n"
2271 			    "encryption.  Good-bye.\n\r"));
2272 			Exit(EXIT_FAILURE);
2273 		    }
2274 		    if (my_want_state_is_dont(TELOPT_ENCRYPT) ||
2275 			my_want_state_is_wont(TELOPT_ENCRYPT)) {
2276 			    (void) printf(gettext(
2277 				"\nServer refused to negotiate encryption.  "
2278 				"Good-bye.\n\r"));
2279 			    Exit(EXIT_FAILURE);
2280 		    }
2281 		    if (encrypt_is_encrypting())
2282 			break;
2283 
2284 		    if (time(0) > timeout) {
2285 			(void) printf(gettext(
2286 				"\nEncryption could not be enabled.  "
2287 				"Good-bye.\n\r"));
2288 			Exit(EXIT_FAILURE);
2289 		    }
2290 		    if (printed_encrypt == B_FALSE) {
2291 			printed_encrypt = B_TRUE;
2292 			(void) printf(gettext(
2293 			    "Waiting for encryption to be negotiated...\n"));
2294 			/*
2295 			 * Turn on MODE_TRAPSIG and then turn off localchars
2296 			 * so that ^C will cause telnet to exit.
2297 			 */
2298 			TerminalNewMode(getconnmode()|MODE_TRAPSIG);
2299 			intr_waiting = 1;
2300 		    }
2301 		    if (intr_happened) {
2302 			(void) printf(gettext(
2303 			    "\nUser requested an interrupt.  Good-bye.\n\r"));
2304 			Exit(EXIT_FAILURE);
2305 		    }
2306 		    telnet_spin();
2307 		}
2308 		if (printed_encrypt) {
2309 			(void) printf(gettext("done.\n"));
2310 			intr_waiting = 0;
2311 			setconnmode(0);
2312 		}
2313 	}
2314 
2315 	for (;;) {
2316 		int schedValue;
2317 
2318 		while ((schedValue = Scheduler(0)) != 0) {
2319 			if (schedValue == -1) {
2320 				setcommandmode();
2321 				return;
2322 			}
2323 		}
2324 
2325 		if (Scheduler(1) == -1) {
2326 			setcommandmode();
2327 			return;
2328 		}
2329 	}
2330 }
2331 
2332 #if	0	/* XXX - this not being in is a bug */
2333 /*
2334  * nextitem()
2335  *
2336  *	Return the address of the next "item" in the TELNET data
2337  * stream.  This will be the address of the next character if
2338  * the current address is a user data character, or it will
2339  * be the address of the character following the TELNET command
2340  * if the current address is a TELNET IAC ("I Am a Command")
2341  * character.
2342  */
2343 
2344 static char *
2345 nextitem(current)
2346 	char *current;
2347 {
2348 	if ((*current&0xff) != IAC) {
2349 		return (current+1);
2350 	}
2351 	switch (*(current+1)&0xff) {
2352 	case DO:
2353 	case DONT:
2354 	case WILL:
2355 	case WONT:
2356 		return (current+3);
2357 	case SB:		/* loop forever looking for the SE */
2358 	{
2359 		register char *look = current+2;
2360 
2361 		for (;;) {
2362 			if ((*look++&0xff) == IAC) {
2363 				if ((*look++&0xff) == SE) {
2364 					return (look);
2365 				}
2366 			}
2367 		}
2368 	}
2369 	default:
2370 		return (current+2);
2371 	}
2372 }
2373 #endif	/* 0 */
2374 
2375 /*
2376  * netclear()
2377  *
2378  *	We are about to do a TELNET SYNCH operation.  Clear
2379  * the path to the network.
2380  *
2381  *	Things are a bit tricky since we may have sent the first
2382  * byte or so of a previous TELNET command into the network.
2383  * So, we have to scan the network buffer from the beginning
2384  * until we are up to where we want to be.
2385  *
2386  *	A side effect of what we do, just to keep things
2387  * simple, is to clear the urgent data pointer.  The principal
2388  * caller should be setting the urgent data pointer AFTER calling
2389  * us in any case.
2390  */
2391 
2392 static void
2393 netclear()
2394 {
2395 #if	0	/* XXX */
2396 	register char *thisitem, *next;
2397 	char *good;
2398 #define	wewant(p)	((nfrontp > p) && ((*p&0xff) == IAC) && \
2399 				((*(p+1)&0xff) != EC) && ((*(p+1)&0xff) != EL))
2400 
2401 	thisitem = netobuf;
2402 
2403 	while ((next = nextitem(thisitem)) <= netobuf.send) {
2404 		thisitem = next;
2405 	}
2406 
2407 	/* Now, thisitem is first before/at boundary. */
2408 
2409 	good = netobuf;	/* where the good bytes go */
2410 
2411 	while (netoring.add > thisitem) {
2412 		if (wewant(thisitem)) {
2413 			int length;
2414 
2415 			next = thisitem;
2416 			do {
2417 				next = nextitem(next);
2418 			} while (wewant(next) && (nfrontp > next));
2419 			length = next-thisitem;
2420 			memcpy(good, thisitem, length);
2421 			good += length;
2422 			thisitem = next;
2423 		} else {
2424 			thisitem = nextitem(thisitem);
2425 		}
2426 	}
2427 
2428 #endif	/* 0 */
2429 }
2430 
2431 /*
2432  * These routines add various telnet commands to the data stream.
2433  */
2434 
2435 /*
2436  * doflush -  Send do timing mark (for network connection flush) & then
2437  * get rid of anything in the output buffer.  Return -1 if there was a
2438  * non-EWOULDBLOCK error on the tty flush, and otherwise return 0.
2439  */
2440 static int
2441 doflush()
2442 {
2443 	NET2ADD(IAC, DO);
2444 	NETADD(TELOPT_TM);
2445 	flushline = 1;
2446 	flushout = 1;
2447 
2448 	/* Drop pending tty output */
2449 	if (ttyflush(1) == -2)
2450 		return (-1);
2451 
2452 	/* do printoption AFTER flush, otherwise the output gets tossed... */
2453 	printoption("SENT", DO, TELOPT_TM);
2454 	return (0);
2455 }
2456 
2457 int
2458 xmitAO()
2459 {
2460 	NET2ADD(IAC, AO);
2461 	printoption("SENT", IAC, AO);
2462 	if (autoflush) {
2463 		if (doflush() == -1)
2464 			return (-1);
2465 	}
2466 	return (0);
2467 }
2468 
2469 
2470 void
2471 xmitEL()
2472 {
2473 	NET2ADD(IAC, EL);
2474 	printoption("SENT", IAC, EL);
2475 }
2476 
2477 void
2478 xmitEC()
2479 {
2480 	NET2ADD(IAC, EC);
2481 	printoption("SENT", IAC, EC);
2482 }
2483 
2484 
2485 int
2486 dosynch()
2487 {
2488 	netclear();			/* clear the path to the network */
2489 	NETADD(IAC);
2490 	setneturg();
2491 	NETADD(DM);
2492 	printoption("SENT", IAC, DM);
2493 	return (1);
2494 }
2495 
2496 int want_status_response = 0;
2497 
2498 int
2499 get_status()
2500 {
2501 	unsigned char tmp[16];
2502 	register unsigned char *cp;
2503 
2504 	if (my_want_state_is_dont(TELOPT_STATUS)) {
2505 		(void) printf("Remote side does not support STATUS option\n");
2506 		return (0);
2507 	}
2508 	cp = tmp;
2509 
2510 	*cp++ = IAC;
2511 	*cp++ = SB;
2512 	*cp++ = TELOPT_STATUS;
2513 	*cp++ = TELQUAL_SEND;
2514 	*cp++ = IAC;
2515 	*cp++ = SE;
2516 	if (NETROOM() >= cp - tmp) {
2517 		ring_supply_data(&netoring, tmp, cp-tmp);
2518 		printsub('>', tmp+2, cp - tmp - 2);
2519 	}
2520 	++want_status_response;
2521 	return (1);
2522 }
2523 
2524 void
2525 intp()
2526 {
2527 	NET2ADD(IAC, IP);
2528 	printoption("SENT", IAC, IP);
2529 	flushline = 1;
2530 	if (autoflush) {
2531 		/* Ignore return as we're ending off anyway. */
2532 		(void) doflush();
2533 	}
2534 	if (autosynch) {
2535 		(void) dosynch();
2536 	}
2537 }
2538 
2539 int
2540 sendbrk()
2541 {
2542 	NET2ADD(IAC, BREAK);
2543 	printoption("SENT", IAC, BREAK);
2544 	flushline = 1;
2545 	if (autoflush) {
2546 		if (doflush() == -1)
2547 			return (-1);
2548 	}
2549 	if (autosynch) {
2550 		(void) dosynch();
2551 	}
2552 	return (0);
2553 }
2554 
2555 void
2556 sendabort()
2557 {
2558 	NET2ADD(IAC, ABORT);
2559 	printoption("SENT", IAC, ABORT);
2560 	flushline = 1;
2561 	if (autoflush) {
2562 		/*
2563 		 * Since sendabort() gets called while aborting,
2564 		 * ignore the doflush() return
2565 		 */
2566 		(void) doflush();
2567 	}
2568 	if (autosynch) {
2569 		(void) dosynch();
2570 	}
2571 }
2572 
2573 void
2574 sendsusp()
2575 {
2576 	NET2ADD(IAC, SUSP);
2577 	printoption("SENT", IAC, SUSP);
2578 	flushline = 1;
2579 	if (autoflush) {
2580 		if (doflush() == -1) {
2581 			/* The following will not return. */
2582 			fatal_tty_error("write");
2583 		}
2584 	}
2585 	if (autosynch) {
2586 		(void) dosynch();
2587 	}
2588 }
2589 
2590 static void
2591 sendeof()
2592 {
2593 	NET2ADD(IAC, xEOF);
2594 	printoption("SENT", IAC, xEOF);
2595 }
2596 
2597 /*
2598  * Send a window size update to the remote system.
2599  */
2600 
2601 void
2602 sendnaws()
2603 {
2604 	unsigned short rows, cols;
2605 	unsigned char tmp[16];
2606 	register unsigned char *cp;
2607 
2608 	if (my_state_is_wont(TELOPT_NAWS))
2609 		return;
2610 
2611 #define	PUTSHORT(cp, x) { if ((*cp++ = ((x)>>8)&0xff) == IAC) *cp++ = IAC; \
2612 			    if ((*cp++ = ((x))&0xff) == IAC) *cp++ = IAC; }
2613 
2614 	if (TerminalWindowSize(&rows, &cols) == 0) {	/* Failed */
2615 		return;
2616 	}
2617 
2618 	cp = tmp;
2619 
2620 	*cp++ = IAC;
2621 	*cp++ = SB;
2622 	*cp++ = TELOPT_NAWS;
2623 	PUTSHORT(cp, cols);
2624 	PUTSHORT(cp, rows);
2625 	*cp++ = IAC;
2626 	*cp++ = SE;
2627 	if (NETROOM() >= cp - tmp) {
2628 		ring_supply_data(&netoring, tmp, cp-tmp);
2629 		printsub('>', tmp+2, cp - tmp - 2);
2630 	}
2631 }
2632 
2633 void
2634 tel_enter_binary(rw)
2635 	int rw;
2636 {
2637 	if (rw&1)
2638 		send_do(TELOPT_BINARY, 1);
2639 	if (rw&2)
2640 		send_will(TELOPT_BINARY, 1);
2641 }
2642 
2643 void
2644 tel_leave_binary(rw)
2645 	int rw;
2646 {
2647 	if (rw&1)
2648 		send_dont(TELOPT_BINARY, 1);
2649 	if (rw&2)
2650 		send_wont(TELOPT_BINARY, 1);
2651 }
2652