xref: /freebsd/contrib/telnet/telnet/telnet.c (revision 0957b409)
1 /*
2  * Copyright (c) 1988, 1990, 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 
34 #if 0
35 #ifndef lint
36 static const char sccsid[] = "@(#)telnet.c	8.4 (Berkeley) 5/30/95";
37 #endif
38 #endif
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include <sys/types.h>
43 
44 /* By the way, we need to include curses.h before telnet.h since,
45  * among other things, telnet.h #defines 'DO', which is a variable
46  * declared in curses.h.
47  */
48 
49 #include <ctype.h>
50 #include <curses.h>
51 #include <signal.h>
52 #include <stdlib.h>
53 #include <term.h>
54 #include <unistd.h>
55 #include <arpa/inet.h>
56 #include <arpa/telnet.h>
57 
58 #include "ring.h"
59 
60 #include "defines.h"
61 #include "externs.h"
62 #include "types.h"
63 #include "general.h"
64 
65 #ifdef	AUTHENTICATION
66 #include <libtelnet/auth.h>
67 #endif
68 #ifdef	ENCRYPTION
69 #include <libtelnet/encrypt.h>
70 #endif
71 #include <libtelnet/misc.h>
72 
73 #define	strip(x) ((my_want_state_is_wont(TELOPT_BINARY)) ? ((x)&0x7f) : (x))
74 
75 static unsigned char	subbuffer[SUBBUFSIZE],
76 			*subpointer, *subend;	 /* buffer for sub-options */
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[256];		/* The combined options */
89 char	do_dont_resp[256];
90 char	will_wont_resp[256];
91 
92 int
93 	eight = 0,
94 	autologin = 0,	/* Autologin anyone? */
95 	skiprc = 0,
96 	connected,
97 	showoptions,
98 	ISend,		/* trying to send network data in */
99 	telnet_debug = 0,
100 	crmod,
101 	netdata,	/* Print out network data flow */
102 	crlf,		/* Should '\r' be mapped to <CR><LF> (or <CR><NUL>)? */
103 	telnetport,
104 	SYNCHing,	/* we are in TELNET SYNCH mode */
105 	flushout,	/* flush output */
106 	autoflush = 0,	/* flush output when interrupting? */
107 	autosynch,	/* send interrupt characters with SYNCH? */
108 	localflow,	/* we handle flow control locally */
109 	restartany,	/* if flow control enabled, restart on any character */
110 	localchars,	/* we recognize interrupt/quit */
111 	donelclchars,	/* the user has set "localchars" */
112 	donebinarytoggle,	/* the user has put us in binary */
113 	dontlecho,	/* do we suppress local echoing right now? */
114 	globalmode,
115 	doaddrlookup = 1, /* do a reverse address lookup? */
116 	clienteof = 0;
117 
118 char *prompt = 0;
119 #ifdef ENCRYPTION
120 char *line;		/* hack around breakage in sra.c :-( !! */
121 #endif
122 
123 cc_t escape;
124 cc_t rlogin;
125 #ifdef	KLUDGELINEMODE
126 cc_t echoc;
127 #endif
128 
129 /*
130  * Telnet receiver states for fsm
131  */
132 #define	TS_DATA		0
133 #define	TS_IAC		1
134 #define	TS_WILL		2
135 #define	TS_WONT		3
136 #define	TS_DO		4
137 #define	TS_DONT		5
138 #define	TS_CR		6
139 #define	TS_SB		7		/* sub-option collection */
140 #define	TS_SE		8		/* looking for sub-option end */
141 
142 static int	telrcv_state;
143 #ifdef	OLD_ENVIRON
144 unsigned char telopt_environ = TELOPT_NEW_ENVIRON;
145 #else
146 # define telopt_environ TELOPT_NEW_ENVIRON
147 #endif
148 
149 jmp_buf	toplevel;
150 
151 int	flushline;
152 int	linemode;
153 
154 #ifdef	KLUDGELINEMODE
155 int	kludgelinemode = 1;
156 #endif
157 
158 static int is_unique(char *, char **, char **);
159 
160 /*
161  * The following are some clocks used to decide how to interpret
162  * the relationship between various variables.
163  */
164 
165 Clocks clocks;
166 
167 /*
168  * Initialize telnet environment.
169  */
170 
171 void
172 init_telnet(void)
173 {
174     env_init();
175 
176     SB_CLEAR();
177     ClearArray(options);
178 
179     connected = ISend = localflow = donebinarytoggle = 0;
180 #ifdef	AUTHENTICATION
181 #ifdef	ENCRYPTION
182     auth_encrypt_connect(connected);
183 #endif
184 #endif
185     restartany = -1;
186 
187     SYNCHing = 0;
188 
189     /* Don't change NetTrace */
190 
191     escape = CONTROL(']');
192     rlogin = _POSIX_VDISABLE;
193 #ifdef	KLUDGELINEMODE
194     echoc = CONTROL('E');
195 #endif
196 
197     flushline = 1;
198     telrcv_state = TS_DATA;
199 }
200 
201 
202 /*
203  * These routines are in charge of sending option negotiations
204  * to the other side.
205  *
206  * The basic idea is that we send the negotiation if either side
207  * is in disagreement as to what the current state should be.
208  */
209 
210 unsigned char ComPortBaudRate[256];
211 
212 void
213 DoBaudRate(char *arg)
214 {
215     char *temp, temp2[10];
216     int i;
217     uint32_t baudrate;
218 
219     errno = 0;
220     baudrate = (uint32_t)strtol(arg, &temp, 10);
221     if (temp[0] != '\0' || (baudrate == 0 && errno != 0))
222 	ExitString("Invalid baud rate provided.\n", 1);
223 
224     for (i = 1; termspeeds[i].speed != -1; i++)
225 	if (baudrate == termspeeds[i].speed)
226 	    break;
227     if (termspeeds[i].speed == -1)
228 	ExitString("Invalid baud rate provided.\n", 1);
229 
230     strlcpy(ComPortBaudRate, arg, sizeof(ComPortBaudRate));
231 
232     if (NETROOM() < sizeof(temp2)) {
233 	ExitString("No room in buffer for baud rate.\n", 1);
234 	/* NOTREACHED */
235     }
236 
237     snprintf(temp2, sizeof(temp2), "%c%c%c%c....%c%c", IAC, SB, TELOPT_COMPORT,
238 	COMPORT_SET_BAUDRATE, IAC, SE);
239 
240     baudrate = htonl(baudrate);
241     memcpy(&temp2[4], &baudrate, sizeof(baudrate));
242     ring_supply_data(&netoring, temp2, sizeof(temp2));
243     printsub('>', &temp[2], sizeof(temp2) - 2);
244 }
245 
246 void
247 send_do(int c, int init)
248 {
249     if (init) {
250 	if (((do_dont_resp[c] == 0) && my_state_is_do(c)) ||
251 				my_want_state_is_do(c))
252 	    return;
253 	set_my_want_state_do(c);
254 	do_dont_resp[c]++;
255     }
256     if (telnetport < 0)
257 	return;
258     NET2ADD(IAC, DO);
259     NETADD(c);
260     printoption("SENT", DO, c);
261 }
262 
263 void
264 send_dont(int c, int init)
265 {
266     if (init) {
267 	if (((do_dont_resp[c] == 0) && my_state_is_dont(c)) ||
268 				my_want_state_is_dont(c))
269 	    return;
270 	set_my_want_state_dont(c);
271 	do_dont_resp[c]++;
272     }
273     if (telnetport < 0)
274 	return;
275     NET2ADD(IAC, DONT);
276     NETADD(c);
277     printoption("SENT", DONT, c);
278 }
279 
280 void
281 send_will(int c, int init)
282 {
283     if (init) {
284 	if (((will_wont_resp[c] == 0) && my_state_is_will(c)) ||
285 				my_want_state_is_will(c))
286 	    return;
287 	set_my_want_state_will(c);
288 	will_wont_resp[c]++;
289     }
290     if (telnetport < 0)
291 	return;
292     NET2ADD(IAC, WILL);
293     NETADD(c);
294     printoption("SENT", WILL, c);
295 }
296 
297 void
298 send_wont(int c, int init)
299 {
300     if (init) {
301 	if (((will_wont_resp[c] == 0) && my_state_is_wont(c)) ||
302 				my_want_state_is_wont(c))
303 	    return;
304 	set_my_want_state_wont(c);
305 	will_wont_resp[c]++;
306     }
307     if (telnetport < 0)
308 	return;
309     NET2ADD(IAC, WONT);
310     NETADD(c);
311     printoption("SENT", WONT, c);
312 }
313 
314 void
315 willoption(int option)
316 {
317 	int new_state_ok = 0;
318 
319 	if (do_dont_resp[option]) {
320 	    --do_dont_resp[option];
321 	    if (do_dont_resp[option] && my_state_is_do(option))
322 		--do_dont_resp[option];
323 	}
324 
325 	if ((do_dont_resp[option] == 0) && my_want_state_is_dont(option)) {
326 
327 	    switch (option) {
328 
329 	    case TELOPT_ECHO:
330 	    case TELOPT_BINARY:
331 	    case TELOPT_SGA:
332 		settimer(modenegotiated);
333 		/* FALLTHROUGH */
334 	    case TELOPT_STATUS:
335 #ifdef	AUTHENTICATION
336 	    case TELOPT_AUTHENTICATION:
337 #endif
338 #ifdef	ENCRYPTION
339 	    case TELOPT_ENCRYPT:
340 #endif /* ENCRYPTION */
341 		new_state_ok = 1;
342 		break;
343 
344 	    case TELOPT_TM:
345 		if (flushout)
346 		    flushout = 0;
347 		/*
348 		 * Special case for TM.  If we get back a WILL,
349 		 * pretend we got back a WONT.
350 		 */
351 		set_my_want_state_dont(option);
352 		set_my_state_dont(option);
353 		return;			/* Never reply to TM will's/wont's */
354 
355 	    case TELOPT_LINEMODE:
356 	    default:
357 		break;
358 	    }
359 
360 	    if (new_state_ok) {
361 		set_my_want_state_do(option);
362 		send_do(option, 0);
363 		setconnmode(0);		/* possibly set new tty mode */
364 	    } else {
365 		do_dont_resp[option]++;
366 		send_dont(option, 0);
367 	    }
368 	}
369 	set_my_state_do(option);
370 #ifdef	ENCRYPTION
371 	if (option == TELOPT_ENCRYPT)
372 		encrypt_send_support();
373 #endif	/* ENCRYPTION */
374 }
375 
376 void
377 wontoption(int option)
378 {
379 	if (do_dont_resp[option]) {
380 	    --do_dont_resp[option];
381 	    if (do_dont_resp[option] && my_state_is_dont(option))
382 		--do_dont_resp[option];
383 	}
384 
385 	if ((do_dont_resp[option] == 0) && my_want_state_is_do(option)) {
386 
387 	    switch (option) {
388 
389 #ifdef	KLUDGELINEMODE
390 	    case TELOPT_SGA:
391 		if (!kludgelinemode)
392 		    break;
393 		/* FALLTHROUGH */
394 #endif
395 	    case TELOPT_ECHO:
396 		settimer(modenegotiated);
397 		break;
398 
399 	    case TELOPT_TM:
400 		if (flushout)
401 		    flushout = 0;
402 		set_my_want_state_dont(option);
403 		set_my_state_dont(option);
404 		return;		/* Never reply to TM will's/wont's */
405 
406 	    default:
407 		break;
408 	    }
409 	    set_my_want_state_dont(option);
410 	    if (my_state_is_do(option))
411 		send_dont(option, 0);
412 	    setconnmode(0);			/* Set new tty mode */
413 	} else if (option == TELOPT_TM) {
414 	    /*
415 	     * Special case for TM.
416 	     */
417 	    if (flushout)
418 		flushout = 0;
419 	    set_my_want_state_dont(option);
420 	}
421 	set_my_state_dont(option);
422 }
423 
424 static void
425 dooption(int option)
426 {
427 	int new_state_ok = 0;
428 
429 	if (will_wont_resp[option]) {
430 	    --will_wont_resp[option];
431 	    if (will_wont_resp[option] && my_state_is_will(option))
432 		--will_wont_resp[option];
433 	}
434 
435 	if (will_wont_resp[option] == 0) {
436 	  if (my_want_state_is_wont(option)) {
437 
438 	    switch (option) {
439 
440 	    case TELOPT_TM:
441 		/*
442 		 * Special case for TM.  We send a WILL, but pretend
443 		 * we sent WONT.
444 		 */
445 		send_will(option, 0);
446 		set_my_want_state_wont(TELOPT_TM);
447 		set_my_state_wont(TELOPT_TM);
448 		return;
449 
450 	    case TELOPT_BINARY:		/* binary mode */
451 	    case TELOPT_NAWS:		/* window size */
452 	    case TELOPT_TSPEED:		/* terminal speed */
453 	    case TELOPT_LFLOW:		/* local flow control */
454 	    case TELOPT_TTYPE:		/* terminal type option */
455 	    case TELOPT_SGA:		/* no big deal */
456 #ifdef	ENCRYPTION
457 	    case TELOPT_ENCRYPT:	/* encryption variable option */
458 #endif	/* ENCRYPTION */
459 		new_state_ok = 1;
460 		break;
461 
462 	    case TELOPT_NEW_ENVIRON:	/* New environment variable option */
463 #ifdef	OLD_ENVIRON
464 		if (my_state_is_will(TELOPT_OLD_ENVIRON))
465 			send_wont(TELOPT_OLD_ENVIRON, 1); /* turn off the old */
466 		goto env_common;
467 	    case TELOPT_OLD_ENVIRON:	/* Old environment variable option */
468 		if (my_state_is_will(TELOPT_NEW_ENVIRON))
469 			break;		/* Don't enable if new one is in use! */
470 	    env_common:
471 		telopt_environ = option;
472 #endif
473 		new_state_ok = 1;
474 		break;
475 
476 #ifdef	AUTHENTICATION
477 	    case TELOPT_AUTHENTICATION:
478 		if (autologin)
479 			new_state_ok = 1;
480 		break;
481 #endif
482 
483 	    case TELOPT_XDISPLOC:	/* X Display location */
484 		if (env_getvalue("DISPLAY"))
485 		    new_state_ok = 1;
486 		break;
487 
488 	    case TELOPT_LINEMODE:
489 #ifdef	KLUDGELINEMODE
490 		kludgelinemode = 0;
491 		send_do(TELOPT_SGA, 1);
492 #endif
493 		set_my_want_state_will(TELOPT_LINEMODE);
494 		send_will(option, 0);
495 		set_my_state_will(TELOPT_LINEMODE);
496 		slc_init();
497 		return;
498 
499 	    case TELOPT_ECHO:		/* We're never going to echo... */
500 	    default:
501 		break;
502 	    }
503 
504 	    if (new_state_ok) {
505 		set_my_want_state_will(option);
506 		send_will(option, 0);
507 		setconnmode(0);			/* Set new tty mode */
508 	    } else {
509 		will_wont_resp[option]++;
510 		send_wont(option, 0);
511 	    }
512 	  } else {
513 	    /*
514 	     * Handle options that need more things done after the
515 	     * other side has acknowledged the option.
516 	     */
517 	    switch (option) {
518 	    case TELOPT_LINEMODE:
519 #ifdef	KLUDGELINEMODE
520 		kludgelinemode = 0;
521 		send_do(TELOPT_SGA, 1);
522 #endif
523 		set_my_state_will(option);
524 		slc_init();
525 		send_do(TELOPT_SGA, 0);
526 		return;
527 	    }
528 	  }
529 	}
530 	set_my_state_will(option);
531 }
532 
533 static void
534 dontoption(int option)
535 {
536 
537 	if (will_wont_resp[option]) {
538 	    --will_wont_resp[option];
539 	    if (will_wont_resp[option] && my_state_is_wont(option))
540 		--will_wont_resp[option];
541 	}
542 
543 	if ((will_wont_resp[option] == 0) && my_want_state_is_will(option)) {
544 	    switch (option) {
545 	    case TELOPT_LINEMODE:
546 		linemode = 0;	/* put us back to the default state */
547 		break;
548 #ifdef	OLD_ENVIRON
549 	    case TELOPT_NEW_ENVIRON:
550 		/*
551 		 * The new environ option wasn't recognized, try
552 		 * the old one.
553 		 */
554 		send_will(TELOPT_OLD_ENVIRON, 1);
555 		telopt_environ = TELOPT_OLD_ENVIRON;
556 		break;
557 #endif
558 	    }
559 	    /* we always accept a DONT */
560 	    set_my_want_state_wont(option);
561 	    if (my_state_is_will(option))
562 		send_wont(option, 0);
563 	    setconnmode(0);			/* Set new tty mode */
564 	}
565 	set_my_state_wont(option);
566 }
567 
568 /*
569  * Given a buffer returned by tgetent(), this routine will turn
570  * the pipe separated list of names in the buffer into an array
571  * of pointers to null terminated names.  We toss out any bad,
572  * duplicate, or verbose names (names with spaces).
573  */
574 
575 static const char *name_unknown = "UNKNOWN";
576 static const char *unknown[] = { NULL, NULL };
577 
578 static const char **
579 mklist(char *buf, char *name)
580 {
581 	int n;
582 	char c, *cp, **argvp, *cp2, **argv, **avt;
583 
584 	if (name) {
585 		if (strlen(name) > 40) {
586 			name = 0;
587 			unknown[0] = name_unknown;
588 		} else {
589 			unknown[0] = name;
590 			upcase(name);
591 		}
592 	} else
593 		unknown[0] = name_unknown;
594 	/*
595 	 * Count up the number of names.
596 	 */
597 	for (n = 1, cp = buf; *cp && *cp != ':'; cp++) {
598 		if (*cp == '|')
599 			n++;
600 	}
601 	/*
602 	 * Allocate an array to put the name pointers into
603 	 */
604 	argv = (char **)malloc((n+3)*sizeof(char *));
605 	if (argv == 0)
606 		return(unknown);
607 
608 	/*
609 	 * Fill up the array of pointers to names.
610 	 */
611 	*argv = 0;
612 	argvp = argv+1;
613 	n = 0;
614 	for (cp = cp2 = buf; (c = *cp);  cp++) {
615 		if (c == '|' || c == ':') {
616 			*cp++ = '\0';
617 			/*
618 			 * Skip entries that have spaces or are over 40
619 			 * characters long.  If this is our environment
620 			 * name, then put it up front.  Otherwise, as
621 			 * long as this is not a duplicate name (case
622 			 * insensitive) add it to the list.
623 			 */
624 			if (n || (cp - cp2 > 41))
625 				;
626 			else if (name && (strncasecmp(name, cp2, cp-cp2) == 0))
627 				*argv = cp2;
628 			else if (is_unique(cp2, argv+1, argvp))
629 				*argvp++ = cp2;
630 			if (c == ':')
631 				break;
632 			/*
633 			 * Skip multiple delimiters. Reset cp2 to
634 			 * the beginning of the next name. Reset n,
635 			 * the flag for names with spaces.
636 			 */
637 			while ((c = *cp) == '|')
638 				cp++;
639 			cp2 = cp;
640 			n = 0;
641 		}
642 		/*
643 		 * Skip entries with spaces or non-ascii values.
644 		 * Convert lower case letters to upper case.
645 		 */
646 		if ((c == ' ') || !isascii(c))
647 			n = 1;
648 		else if (islower(c))
649 			*cp = toupper(c);
650 	}
651 
652 	/*
653 	 * Check for an old V6 2 character name.  If the second
654 	 * name points to the beginning of the buffer, and is
655 	 * only 2 characters long, move it to the end of the array.
656 	 */
657 	if ((argv[1] == buf) && (strlen(argv[1]) == 2)) {
658 		--argvp;
659 		for (avt = &argv[1]; avt < argvp; avt++)
660 			*avt = *(avt+1);
661 		*argvp++ = buf;
662 	}
663 
664 	/*
665 	 * Duplicate last name, for TTYPE option, and null
666 	 * terminate the array.  If we didn't find a match on
667 	 * our terminal name, put that name at the beginning.
668 	 */
669 	cp = *(argvp-1);
670 	*argvp++ = cp;
671 	*argvp = 0;
672 
673 	if (*argv == 0) {
674 		if (name)
675 			*argv = name;
676 		else {
677 			--argvp;
678 			for (avt = argv; avt < argvp; avt++)
679 				*avt = *(avt+1);
680 		}
681 	}
682 	if (*argv)
683 		return((const char **)argv);
684 	else
685 		return(unknown);
686 }
687 
688 static int
689 is_unique(char *name, char **as, char **ae)
690 {
691 	char **ap;
692 	int n;
693 
694 	n = strlen(name) + 1;
695 	for (ap = as; ap < ae; ap++)
696 		if (strncasecmp(*ap, name, n) == 0)
697 			return(0);
698 	return (1);
699 }
700 
701 #ifdef	TERMCAP
702 char termbuf[1024];
703 
704 /*ARGSUSED*/
705 static int
706 setupterm(char *tname, int fd, int *errp)
707 {
708 	if (tgetent(termbuf, tname) == 1) {
709 		termbuf[1023] = '\0';
710 		if (errp)
711 			*errp = 1;
712 		return(0);
713 	}
714 	if (errp)
715 		*errp = 0;
716 	return(-1);
717 }
718 #else
719 #define	termbuf	ttytype
720 extern char ttytype[];
721 #endif
722 
723 int resettermname = 1;
724 
725 static const char *
726 gettermname(void)
727 {
728 	char *tname;
729 	static const char **tnamep = 0;
730 	static const char **next;
731 	int err;
732 
733 	if (resettermname) {
734 		resettermname = 0;
735 		if (tnamep && tnamep != unknown)
736 			free(tnamep);
737 		if ((tname = env_getvalue("TERM")) &&
738 				(setupterm(tname, 1, &err) == 0)) {
739 			tnamep = mklist(termbuf, tname);
740 		} else {
741 			if (tname && (strlen(tname) <= 40)) {
742 				unknown[0] = tname;
743 				upcase(tname);
744 			} else
745 				unknown[0] = name_unknown;
746 			tnamep = unknown;
747 		}
748 		next = tnamep;
749 	}
750 	if (*next == 0)
751 		next = tnamep;
752 	return(*next++);
753 }
754 /*
755  * suboption()
756  *
757  *	Look at the sub-option buffer, and try to be helpful to the other
758  * side.
759  *
760  *	Currently we recognize:
761  *
762  *		Terminal type, send request.
763  *		Terminal speed (send request).
764  *		Local flow control (is request).
765  *		Linemode
766  */
767 
768 static void
769 suboption(void)
770 {
771     unsigned char subchar;
772 
773     printsub('<', subbuffer, SB_LEN()+2);
774     switch (subchar = SB_GET()) {
775     case TELOPT_TTYPE:
776 	if (my_want_state_is_wont(TELOPT_TTYPE))
777 	    return;
778 	if (SB_EOF() || SB_GET() != TELQUAL_SEND) {
779 	    return;
780 	} else {
781 	    const char *name;
782 	    unsigned char temp[50];
783 	    int len;
784 
785 	    name = gettermname();
786 	    len = strlen(name) + 4 + 2;
787 	    if (len < NETROOM()) {
788 		sprintf(temp, "%c%c%c%c%s%c%c", IAC, SB, TELOPT_TTYPE,
789 				TELQUAL_IS, name, IAC, SE);
790 		ring_supply_data(&netoring, temp, len);
791 		printsub('>', &temp[2], len-2);
792 	    } else {
793 		ExitString("No room in buffer for terminal type.\n", 1);
794 		/*NOTREACHED*/
795 	    }
796 	}
797 	break;
798     case TELOPT_TSPEED:
799 	if (my_want_state_is_wont(TELOPT_TSPEED))
800 	    return;
801 	if (SB_EOF())
802 	    return;
803 	if (SB_GET() == TELQUAL_SEND) {
804 	    long ospeed, ispeed;
805 	    unsigned char temp[50];
806 	    int len;
807 
808 	    TerminalSpeeds(&ispeed, &ospeed);
809 
810 	    sprintf((char *)temp, "%c%c%c%c%ld,%ld%c%c", IAC, SB, TELOPT_TSPEED,
811 		    TELQUAL_IS, ospeed, ispeed, IAC, SE);
812 	    len = strlen((char *)temp+4) + 4;	/* temp[3] is 0 ... */
813 
814 	    if (len < NETROOM()) {
815 		ring_supply_data(&netoring, temp, len);
816 		printsub('>', temp+2, len - 2);
817 	    }
818 /*@*/	    else printf("lm_will: not enough room in buffer\n");
819 	}
820 	break;
821     case TELOPT_LFLOW:
822 	if (my_want_state_is_wont(TELOPT_LFLOW))
823 	    return;
824 	if (SB_EOF())
825 	    return;
826 	switch(SB_GET()) {
827 	case LFLOW_RESTART_ANY:
828 	    restartany = 1;
829 	    break;
830 	case LFLOW_RESTART_XON:
831 	    restartany = 0;
832 	    break;
833 	case LFLOW_ON:
834 	    localflow = 1;
835 	    break;
836 	case LFLOW_OFF:
837 	    localflow = 0;
838 	    break;
839 	default:
840 	    return;
841 	}
842 	setcommandmode();
843 	setconnmode(0);
844 	break;
845 
846     case TELOPT_LINEMODE:
847 	if (my_want_state_is_wont(TELOPT_LINEMODE))
848 	    return;
849 	if (SB_EOF())
850 	    return;
851 	switch (SB_GET()) {
852 	case WILL:
853 	    lm_will(subpointer, SB_LEN());
854 	    break;
855 	case WONT:
856 	    lm_wont(subpointer, SB_LEN());
857 	    break;
858 	case DO:
859 	    lm_do(subpointer, SB_LEN());
860 	    break;
861 	case DONT:
862 	    lm_dont(subpointer, SB_LEN());
863 	    break;
864 	case LM_SLC:
865 	    slc(subpointer, SB_LEN());
866 	    break;
867 	case LM_MODE:
868 	    lm_mode(subpointer, SB_LEN(), 0);
869 	    break;
870 	default:
871 	    break;
872 	}
873 	break;
874 
875 #ifdef	OLD_ENVIRON
876     case TELOPT_OLD_ENVIRON:
877 #endif
878     case TELOPT_NEW_ENVIRON:
879 	if (SB_EOF())
880 	    return;
881 	switch(SB_PEEK()) {
882 	case TELQUAL_IS:
883 	case TELQUAL_INFO:
884 	    if (my_want_state_is_dont(subchar))
885 		return;
886 	    break;
887 	case TELQUAL_SEND:
888 	    if (my_want_state_is_wont(subchar)) {
889 		return;
890 	    }
891 	    break;
892 	default:
893 	    return;
894 	}
895 	env_opt(subpointer, SB_LEN());
896 	break;
897 
898     case TELOPT_XDISPLOC:
899 	if (my_want_state_is_wont(TELOPT_XDISPLOC))
900 	    return;
901 	if (SB_EOF())
902 	    return;
903 	if (SB_GET() == TELQUAL_SEND) {
904 	    unsigned char temp[50], *dp;
905 	    int len;
906 
907 	    if ((dp = env_getvalue("DISPLAY")) == NULL ||
908 		strlen(dp) > sizeof(temp) - 7) {
909 		/*
910 		 * Something happened, we no longer have a DISPLAY
911 		 * variable.  Or it is too long.  So, turn off the option.
912 		 */
913 		send_wont(TELOPT_XDISPLOC, 1);
914 		break;
915 	    }
916 	    snprintf(temp, sizeof(temp), "%c%c%c%c%s%c%c", IAC, SB,
917 		    TELOPT_XDISPLOC, TELQUAL_IS, dp, IAC, SE);
918 	    len = strlen((char *)temp+4) + 4;	/* temp[3] is 0 ... */
919 
920 	    if (len < NETROOM()) {
921 		ring_supply_data(&netoring, temp, len);
922 		printsub('>', temp+2, len - 2);
923 	    }
924 /*@*/	    else printf("lm_will: not enough room in buffer\n");
925 	}
926 	break;
927 
928 #ifdef	AUTHENTICATION
929 	case TELOPT_AUTHENTICATION: {
930 		if (!autologin)
931 			break;
932 		if (SB_EOF())
933 			return;
934 		switch(SB_GET()) {
935 		case TELQUAL_IS:
936 			if (my_want_state_is_dont(TELOPT_AUTHENTICATION))
937 				return;
938 			auth_is(subpointer, SB_LEN());
939 			break;
940 		case TELQUAL_SEND:
941 			if (my_want_state_is_wont(TELOPT_AUTHENTICATION))
942 				return;
943 			auth_send(subpointer, SB_LEN());
944 			break;
945 		case TELQUAL_REPLY:
946 			if (my_want_state_is_wont(TELOPT_AUTHENTICATION))
947 				return;
948 			auth_reply(subpointer, SB_LEN());
949 			break;
950 		case TELQUAL_NAME:
951 			if (my_want_state_is_dont(TELOPT_AUTHENTICATION))
952 				return;
953 			auth_name(subpointer, SB_LEN());
954 			break;
955 		}
956 	}
957 	break;
958 #endif
959 #ifdef	ENCRYPTION
960 	case TELOPT_ENCRYPT:
961 		if (SB_EOF())
962 			return;
963 		switch(SB_GET()) {
964 		case ENCRYPT_START:
965 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
966 				return;
967 			encrypt_start(subpointer, SB_LEN());
968 			break;
969 		case ENCRYPT_END:
970 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
971 				return;
972 			encrypt_end();
973 			break;
974 		case ENCRYPT_SUPPORT:
975 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
976 				return;
977 			encrypt_support(subpointer, SB_LEN());
978 			break;
979 		case ENCRYPT_REQSTART:
980 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
981 				return;
982 			encrypt_request_start(subpointer, SB_LEN());
983 			break;
984 		case ENCRYPT_REQEND:
985 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
986 				return;
987 			/*
988 			 * We can always send an REQEND so that we cannot
989 			 * get stuck encrypting.  We should only get this
990 			 * if we have been able to get in the correct mode
991 			 * anyhow.
992 			 */
993 			encrypt_request_end();
994 			break;
995 		case ENCRYPT_IS:
996 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
997 				return;
998 			encrypt_is(subpointer, SB_LEN());
999 			break;
1000 		case ENCRYPT_REPLY:
1001 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1002 				return;
1003 			encrypt_reply(subpointer, SB_LEN());
1004 			break;
1005 		case ENCRYPT_ENC_KEYID:
1006 			if (my_want_state_is_dont(TELOPT_ENCRYPT))
1007 				return;
1008 			encrypt_enc_keyid(subpointer, SB_LEN());
1009 			break;
1010 		case ENCRYPT_DEC_KEYID:
1011 			if (my_want_state_is_wont(TELOPT_ENCRYPT))
1012 				return;
1013 			encrypt_dec_keyid(subpointer, SB_LEN());
1014 			break;
1015 		default:
1016 			break;
1017 		}
1018 		break;
1019 #endif	/* ENCRYPTION */
1020     default:
1021 	break;
1022     }
1023 }
1024 
1025 static unsigned char str_lm[] = { IAC, SB, TELOPT_LINEMODE, 0, 0, IAC, SE };
1026 
1027 void
1028 lm_will(unsigned char *cmd, int len)
1029 {
1030     if (len < 1) {
1031 /*@*/	printf("lm_will: no command!!!\n");	/* Should not happen... */
1032 	return;
1033     }
1034     switch(cmd[0]) {
1035     case LM_FORWARDMASK:	/* We shouldn't ever get this... */
1036     default:
1037 	str_lm[3] = DONT;
1038 	str_lm[4] = cmd[0];
1039 	if (NETROOM() > (int)sizeof(str_lm)) {
1040 	    ring_supply_data(&netoring, str_lm, sizeof(str_lm));
1041 	    printsub('>', &str_lm[2], sizeof(str_lm)-2);
1042 	}
1043 /*@*/	else printf("lm_will: not enough room in buffer\n");
1044 	break;
1045     }
1046 }
1047 
1048 void
1049 lm_wont(unsigned char *cmd, int len)
1050 {
1051     if (len < 1) {
1052 /*@*/	printf("lm_wont: no command!!!\n");	/* Should not happen... */
1053 	return;
1054     }
1055     switch(cmd[0]) {
1056     case LM_FORWARDMASK:	/* We shouldn't ever get this... */
1057     default:
1058 	/* We are always DONT, so don't respond */
1059 	return;
1060     }
1061 }
1062 
1063 void
1064 lm_do(unsigned char *cmd, int len)
1065 {
1066     if (len < 1) {
1067 /*@*/	printf("lm_do: no command!!!\n");	/* Should not happen... */
1068 	return;
1069     }
1070     switch(cmd[0]) {
1071     case LM_FORWARDMASK:
1072     default:
1073 	str_lm[3] = WONT;
1074 	str_lm[4] = cmd[0];
1075 	if (NETROOM() > (int)sizeof(str_lm)) {
1076 	    ring_supply_data(&netoring, str_lm, sizeof(str_lm));
1077 	    printsub('>', &str_lm[2], sizeof(str_lm)-2);
1078 	}
1079 /*@*/	else printf("lm_do: not enough room in buffer\n");
1080 	break;
1081     }
1082 }
1083 
1084 void
1085 lm_dont(unsigned char *cmd, int len)
1086 {
1087     if (len < 1) {
1088 /*@*/	printf("lm_dont: no command!!!\n");	/* Should not happen... */
1089 	return;
1090     }
1091     switch(cmd[0]) {
1092     case LM_FORWARDMASK:
1093     default:
1094 	/* we are always WONT, so don't respond */
1095 	break;
1096     }
1097 }
1098 
1099 static unsigned char str_lm_mode[] = {
1100 	IAC, SB, TELOPT_LINEMODE, LM_MODE, 0, IAC, SE
1101 };
1102 
1103 void
1104 lm_mode(unsigned char *cmd, int len, int init)
1105 {
1106 	if (len != 1)
1107 		return;
1108 	if ((linemode&MODE_MASK&~MODE_ACK) == *cmd)
1109 		return;
1110 	if (*cmd&MODE_ACK)
1111 		return;
1112 	linemode = *cmd&(MODE_MASK&~MODE_ACK);
1113 	str_lm_mode[4] = linemode;
1114 	if (!init)
1115 	    str_lm_mode[4] |= MODE_ACK;
1116 	if (NETROOM() > (int)sizeof(str_lm_mode)) {
1117 	    ring_supply_data(&netoring, str_lm_mode, sizeof(str_lm_mode));
1118 	    printsub('>', &str_lm_mode[2], sizeof(str_lm_mode)-2);
1119 	}
1120 /*@*/	else printf("lm_mode: not enough room in buffer\n");
1121 	setconnmode(0);	/* set changed mode */
1122 }
1123 
1124 
1125 
1126 /*
1127  * slc()
1128  * Handle special character suboption of LINEMODE.
1129  */
1130 
1131 struct spc {
1132 	cc_t val;
1133 	cc_t *valp;
1134 	char flags;	/* Current flags & level */
1135 	char mylevel;	/* Maximum level & flags */
1136 } spc_data[NSLC+1];
1137 
1138 #define SLC_IMPORT	0
1139 #define	SLC_EXPORT	1
1140 #define SLC_RVALUE	2
1141 static int slc_mode = SLC_EXPORT;
1142 
1143 void
1144 slc_init(void)
1145 {
1146 	struct spc *spcp;
1147 
1148 	localchars = 1;
1149 	for (spcp = spc_data; spcp < &spc_data[NSLC+1]; spcp++) {
1150 		spcp->val = 0;
1151 		spcp->valp = 0;
1152 		spcp->flags = spcp->mylevel = SLC_NOSUPPORT;
1153 	}
1154 
1155 #define	initfunc(func, flags) { \
1156 					spcp = &spc_data[func]; \
1157 					if ((spcp->valp = tcval(func))) { \
1158 					    spcp->val = *spcp->valp; \
1159 					    spcp->mylevel = SLC_VARIABLE|flags; \
1160 					} else { \
1161 					    spcp->val = 0; \
1162 					    spcp->mylevel = SLC_DEFAULT; \
1163 					} \
1164 				    }
1165 
1166 	initfunc(SLC_SYNCH, 0);
1167 	/* No BRK */
1168 	initfunc(SLC_AO, 0);
1169 	initfunc(SLC_AYT, 0);
1170 	/* No EOR */
1171 	initfunc(SLC_ABORT, SLC_FLUSHIN|SLC_FLUSHOUT);
1172 	initfunc(SLC_EOF, 0);
1173 #ifndef	SYSV_TERMIO
1174 	initfunc(SLC_SUSP, SLC_FLUSHIN);
1175 #endif
1176 	initfunc(SLC_EC, 0);
1177 	initfunc(SLC_EL, 0);
1178 #ifndef	SYSV_TERMIO
1179 	initfunc(SLC_EW, 0);
1180 	initfunc(SLC_RP, 0);
1181 	initfunc(SLC_LNEXT, 0);
1182 #endif
1183 	initfunc(SLC_XON, 0);
1184 	initfunc(SLC_XOFF, 0);
1185 #ifdef	SYSV_TERMIO
1186 	spc_data[SLC_XON].mylevel = SLC_CANTCHANGE;
1187 	spc_data[SLC_XOFF].mylevel = SLC_CANTCHANGE;
1188 #endif
1189 	initfunc(SLC_FORW1, 0);
1190 #ifdef	USE_TERMIO
1191 	initfunc(SLC_FORW2, 0);
1192 	/* No FORW2 */
1193 #endif
1194 
1195 	initfunc(SLC_IP, SLC_FLUSHIN|SLC_FLUSHOUT);
1196 #undef	initfunc
1197 
1198 	if (slc_mode == SLC_EXPORT)
1199 		slc_export();
1200 	else
1201 		slc_import(1);
1202 
1203 }
1204 
1205 void
1206 slcstate(void)
1207 {
1208     printf("Special characters are %s values\n",
1209 		slc_mode == SLC_IMPORT ? "remote default" :
1210 		slc_mode == SLC_EXPORT ? "local" :
1211 					 "remote");
1212 }
1213 
1214 void
1215 slc_mode_export(void)
1216 {
1217     slc_mode = SLC_EXPORT;
1218     if (my_state_is_will(TELOPT_LINEMODE))
1219 	slc_export();
1220 }
1221 
1222 void
1223 slc_mode_import(int def)
1224 {
1225     slc_mode = def ? SLC_IMPORT : SLC_RVALUE;
1226     if (my_state_is_will(TELOPT_LINEMODE))
1227 	slc_import(def);
1228 }
1229 
1230 unsigned char slc_import_val[] = {
1231 	IAC, SB, TELOPT_LINEMODE, LM_SLC, 0, SLC_VARIABLE, 0, IAC, SE
1232 };
1233 unsigned char slc_import_def[] = {
1234 	IAC, SB, TELOPT_LINEMODE, LM_SLC, 0, SLC_DEFAULT, 0, IAC, SE
1235 };
1236 
1237 void
1238 slc_import(int def)
1239 {
1240     if (NETROOM() > (int)sizeof(slc_import_val)) {
1241 	if (def) {
1242 	    ring_supply_data(&netoring, slc_import_def, sizeof(slc_import_def));
1243 	    printsub('>', &slc_import_def[2], sizeof(slc_import_def)-2);
1244 	} else {
1245 	    ring_supply_data(&netoring, slc_import_val, sizeof(slc_import_val));
1246 	    printsub('>', &slc_import_val[2], sizeof(slc_import_val)-2);
1247 	}
1248     }
1249 /*@*/ else printf("slc_import: not enough room\n");
1250 }
1251 
1252 void
1253 slc_export(void)
1254 {
1255     struct spc *spcp;
1256 
1257     TerminalDefaultChars();
1258 
1259     slc_start_reply();
1260     for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
1261 	if (spcp->mylevel != SLC_NOSUPPORT) {
1262 	    if (spcp->val == (cc_t)(_POSIX_VDISABLE))
1263 		spcp->flags = SLC_NOSUPPORT;
1264 	    else
1265 		spcp->flags = spcp->mylevel;
1266 	    if (spcp->valp)
1267 		spcp->val = *spcp->valp;
1268 	    slc_add_reply(spcp - spc_data, spcp->flags, spcp->val);
1269 	}
1270     }
1271     slc_end_reply();
1272     (void)slc_update();
1273     setconnmode(1);	/* Make sure the character values are set */
1274 }
1275 
1276 void
1277 slc(unsigned char *cp, int len)
1278 {
1279 	struct spc *spcp;
1280 	int func,level;
1281 
1282 	slc_start_reply();
1283 
1284 	for (; len >= 3; len -=3, cp +=3) {
1285 
1286 		func = cp[SLC_FUNC];
1287 
1288 		if (func == 0) {
1289 			/*
1290 			 * Client side: always ignore 0 function.
1291 			 */
1292 			continue;
1293 		}
1294 		if (func > NSLC) {
1295 			if ((cp[SLC_FLAGS] & SLC_LEVELBITS) != SLC_NOSUPPORT)
1296 				slc_add_reply(func, SLC_NOSUPPORT, 0);
1297 			continue;
1298 		}
1299 
1300 		spcp = &spc_data[func];
1301 
1302 		level = cp[SLC_FLAGS]&(SLC_LEVELBITS|SLC_ACK);
1303 
1304 		if ((cp[SLC_VALUE] == (unsigned char)spcp->val) &&
1305 		    ((level&SLC_LEVELBITS) == (spcp->flags&SLC_LEVELBITS))) {
1306 			continue;
1307 		}
1308 
1309 		if (level == (SLC_DEFAULT|SLC_ACK)) {
1310 			/*
1311 			 * This is an error condition, the SLC_ACK
1312 			 * bit should never be set for the SLC_DEFAULT
1313 			 * level.  Our best guess to recover is to
1314 			 * ignore the SLC_ACK bit.
1315 			 */
1316 			cp[SLC_FLAGS] &= ~SLC_ACK;
1317 		}
1318 
1319 		if (level == ((spcp->flags&SLC_LEVELBITS)|SLC_ACK)) {
1320 			spcp->val = (cc_t)cp[SLC_VALUE];
1321 			spcp->flags = cp[SLC_FLAGS];	/* include SLC_ACK */
1322 			continue;
1323 		}
1324 
1325 		level &= ~SLC_ACK;
1326 
1327 		if (level <= (spcp->mylevel&SLC_LEVELBITS)) {
1328 			spcp->flags = cp[SLC_FLAGS]|SLC_ACK;
1329 			spcp->val = (cc_t)cp[SLC_VALUE];
1330 		}
1331 		if (level == SLC_DEFAULT) {
1332 			if ((spcp->mylevel&SLC_LEVELBITS) != SLC_DEFAULT)
1333 				spcp->flags = spcp->mylevel;
1334 			else
1335 				spcp->flags = SLC_NOSUPPORT;
1336 		}
1337 		slc_add_reply(func, spcp->flags, spcp->val);
1338 	}
1339 	slc_end_reply();
1340 	if (slc_update())
1341 		setconnmode(1);	/* set the  new character values */
1342 }
1343 
1344 void
1345 slc_check(void)
1346 {
1347     struct spc *spcp;
1348 
1349     slc_start_reply();
1350     for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
1351 	if (spcp->valp && spcp->val != *spcp->valp) {
1352 	    spcp->val = *spcp->valp;
1353 	    if (spcp->val == (cc_t)(_POSIX_VDISABLE))
1354 		spcp->flags = SLC_NOSUPPORT;
1355 	    else
1356 		spcp->flags = spcp->mylevel;
1357 	    slc_add_reply(spcp - spc_data, spcp->flags, spcp->val);
1358 	}
1359     }
1360     slc_end_reply();
1361     setconnmode(1);
1362 }
1363 
1364 unsigned char slc_reply[128];
1365 unsigned char const * const slc_reply_eom = &slc_reply[sizeof(slc_reply)];
1366 unsigned char *slc_replyp;
1367 
1368 void
1369 slc_start_reply(void)
1370 {
1371 	slc_replyp = slc_reply;
1372 	*slc_replyp++ = IAC;
1373 	*slc_replyp++ = SB;
1374 	*slc_replyp++ = TELOPT_LINEMODE;
1375 	*slc_replyp++ = LM_SLC;
1376 }
1377 
1378 void
1379 slc_add_reply(unsigned char func, unsigned char flags, cc_t value)
1380 {
1381 	/* A sequence of up to 6 bytes my be written for this member of the SLC
1382 	 * suboption list by this function.  The end of negotiation command,
1383 	 * which is written by slc_end_reply(), will require 2 additional
1384 	 * bytes.  Do not proceed unless there is sufficient space for these
1385 	 * items.
1386 	 */
1387 	if (&slc_replyp[6+2] > slc_reply_eom)
1388 		return;
1389 	if ((*slc_replyp++ = func) == IAC)
1390 		*slc_replyp++ = IAC;
1391 	if ((*slc_replyp++ = flags) == IAC)
1392 		*slc_replyp++ = IAC;
1393 	if ((*slc_replyp++ = (unsigned char)value) == IAC)
1394 		*slc_replyp++ = IAC;
1395 }
1396 
1397 void
1398 slc_end_reply(void)
1399 {
1400     int len;
1401 
1402     /* The end of negotiation command requires 2 bytes. */
1403     if (&slc_replyp[2] > slc_reply_eom)
1404             return;
1405     *slc_replyp++ = IAC;
1406     *slc_replyp++ = SE;
1407     len = slc_replyp - slc_reply;
1408     if (len <= 6)
1409 	return;
1410     if (NETROOM() > len) {
1411 	ring_supply_data(&netoring, slc_reply, slc_replyp - slc_reply);
1412 	printsub('>', &slc_reply[2], slc_replyp - slc_reply - 2);
1413     }
1414 /*@*/else printf("slc_end_reply: not enough room\n");
1415 }
1416 
1417 int
1418 slc_update(void)
1419 {
1420 	struct spc *spcp;
1421 	int need_update = 0;
1422 
1423 	for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
1424 		if (!(spcp->flags&SLC_ACK))
1425 			continue;
1426 		spcp->flags &= ~SLC_ACK;
1427 		if (spcp->valp && (*spcp->valp != spcp->val)) {
1428 			*spcp->valp = spcp->val;
1429 			need_update = 1;
1430 		}
1431 	}
1432 	return(need_update);
1433 }
1434 
1435 #ifdef	OLD_ENVIRON
1436 # ifdef	ENV_HACK
1437 /*
1438  * Earlier version of telnet/telnetd from the BSD code had
1439  * the definitions of VALUE and VAR reversed.  To ensure
1440  * maximum interoperability, we assume that the server is
1441  * an older BSD server, until proven otherwise.  The newer
1442  * BSD servers should be able to handle either definition,
1443  * so it is better to use the wrong values if we don't
1444  * know what type of server it is.
1445  */
1446 int env_auto = 1;
1447 int old_env_var = OLD_ENV_VAR;
1448 int old_env_value = OLD_ENV_VALUE;
1449 # else
1450 #  define old_env_var OLD_ENV_VAR
1451 #  define old_env_value OLD_ENV_VALUE
1452 # endif
1453 #endif
1454 
1455 void
1456 env_opt(unsigned char *buf, int len)
1457 {
1458 	unsigned char *ep = 0, *epc = 0;
1459 	int i;
1460 
1461 	switch(buf[0]&0xff) {
1462 	case TELQUAL_SEND:
1463 		env_opt_start();
1464 		if (len == 1) {
1465 			env_opt_add(NULL);
1466 		} else for (i = 1; i < len; i++) {
1467 			switch (buf[i]&0xff) {
1468 #ifdef	OLD_ENVIRON
1469 			case OLD_ENV_VAR:
1470 # ifdef	ENV_HACK
1471 				if (telopt_environ == TELOPT_OLD_ENVIRON
1472 				    && env_auto) {
1473 					/* Server has the same definitions */
1474 					old_env_var = OLD_ENV_VAR;
1475 					old_env_value = OLD_ENV_VALUE;
1476 				}
1477 				/* FALLTHROUGH */
1478 # endif
1479 			case OLD_ENV_VALUE:
1480 				/*
1481 				 * Although OLD_ENV_VALUE is not legal, we will
1482 				 * still recognize it, just in case it is an
1483 				 * old server that has VAR & VALUE mixed up...
1484 				 */
1485 				/* FALLTHROUGH */
1486 #else
1487 			case NEW_ENV_VAR:
1488 #endif
1489 			case ENV_USERVAR:
1490 				if (ep) {
1491 					*epc = 0;
1492 					env_opt_add(ep);
1493 				}
1494 				ep = epc = &buf[i+1];
1495 				break;
1496 			case ENV_ESC:
1497 				i++;
1498 				/*FALLTHROUGH*/
1499 			default:
1500 				if (epc)
1501 					*epc++ = buf[i];
1502 				break;
1503 			}
1504 		}
1505 		if (ep) {
1506 			*epc = 0;
1507 			env_opt_add(ep);
1508 		}
1509 		env_opt_end(1);
1510 		break;
1511 
1512 	case TELQUAL_IS:
1513 	case TELQUAL_INFO:
1514 		/* Ignore for now.  We shouldn't get it anyway. */
1515 		break;
1516 
1517 	default:
1518 		break;
1519 	}
1520 }
1521 
1522 #define	OPT_REPLY_SIZE	(2 * SUBBUFSIZE)
1523 unsigned char *opt_reply = NULL;
1524 unsigned char *opt_replyp;
1525 unsigned char *opt_replyend;
1526 
1527 void
1528 env_opt_start(void)
1529 {
1530 	if (opt_reply)
1531 		opt_reply = (unsigned char *)realloc(opt_reply, OPT_REPLY_SIZE);
1532 	else
1533 		opt_reply = (unsigned char *)malloc(OPT_REPLY_SIZE);
1534 	if (opt_reply == NULL) {
1535 /*@*/		printf("env_opt_start: malloc()/realloc() failed!!!\n");
1536 		opt_reply = opt_replyp = opt_replyend = NULL;
1537 		return;
1538 	}
1539 	opt_replyp = opt_reply;
1540 	opt_replyend = opt_reply + OPT_REPLY_SIZE;
1541 	*opt_replyp++ = IAC;
1542 	*opt_replyp++ = SB;
1543 	*opt_replyp++ = telopt_environ;
1544 	*opt_replyp++ = TELQUAL_IS;
1545 }
1546 
1547 void
1548 env_opt_start_info(void)
1549 {
1550 	env_opt_start();
1551 	if (opt_replyp)
1552 	    opt_replyp[-1] = TELQUAL_INFO;
1553 }
1554 
1555 void
1556 env_opt_add(unsigned char *ep)
1557 {
1558 	unsigned char *vp, c;
1559 
1560 	if (opt_reply == NULL)		/*XXX*/
1561 		return;			/*XXX*/
1562 
1563 	if (ep == NULL || *ep == '\0') {
1564 		/* Send user defined variables first. */
1565 		env_default(1, 0);
1566 		while ((ep = env_default(0, 0)))
1567 			env_opt_add(ep);
1568 
1569 		/* Now add the list of well know variables.  */
1570 		env_default(1, 1);
1571 		while ((ep = env_default(0, 1)))
1572 			env_opt_add(ep);
1573 		return;
1574 	}
1575 	vp = env_getvalue(ep);
1576         if (opt_replyp + (vp ? 2 * strlen((char *)vp) : 0) +
1577                                 2 * strlen((char *)ep) + 6 > opt_replyend)
1578         {
1579 		int len;
1580 		opt_replyend += OPT_REPLY_SIZE;
1581 		len = opt_replyend - opt_reply;
1582 		opt_reply = (unsigned char *)realloc(opt_reply, len);
1583 		if (opt_reply == NULL) {
1584 /*@*/			printf("env_opt_add: realloc() failed!!!\n");
1585 			opt_reply = opt_replyp = opt_replyend = NULL;
1586 			return;
1587 		}
1588 		opt_replyp = opt_reply + len - (opt_replyend - opt_replyp);
1589 		opt_replyend = opt_reply + len;
1590 	}
1591 	if (opt_welldefined(ep))
1592 #ifdef	OLD_ENVIRON
1593 		if (telopt_environ == TELOPT_OLD_ENVIRON)
1594 			*opt_replyp++ = old_env_var;
1595 		else
1596 #endif
1597 			*opt_replyp++ = NEW_ENV_VAR;
1598 	else
1599 		*opt_replyp++ = ENV_USERVAR;
1600 	for (;;) {
1601 		while ((c = *ep++)) {
1602 			if (opt_replyp + (2 + 2) > opt_replyend)
1603 				return;
1604 			switch(c&0xff) {
1605 			case IAC:
1606 				*opt_replyp++ = IAC;
1607 				break;
1608 			case NEW_ENV_VAR:
1609 			case NEW_ENV_VALUE:
1610 			case ENV_ESC:
1611 			case ENV_USERVAR:
1612 				*opt_replyp++ = ENV_ESC;
1613 				break;
1614 			}
1615 			*opt_replyp++ = c;
1616 		}
1617 		if ((ep = vp)) {
1618 			if (opt_replyp + (1 + 2 + 2) > opt_replyend)
1619 				return;
1620 #ifdef	OLD_ENVIRON
1621 			if (telopt_environ == TELOPT_OLD_ENVIRON)
1622 				*opt_replyp++ = old_env_value;
1623 			else
1624 #endif
1625 				*opt_replyp++ = NEW_ENV_VALUE;
1626 			vp = NULL;
1627 		} else
1628 			break;
1629 	}
1630 }
1631 
1632 int
1633 opt_welldefined(const char *ep)
1634 {
1635 	if ((strcmp(ep, "USER") == 0) ||
1636 	    (strcmp(ep, "DISPLAY") == 0) ||
1637 	    (strcmp(ep, "PRINTER") == 0) ||
1638 	    (strcmp(ep, "SYSTEMTYPE") == 0) ||
1639 	    (strcmp(ep, "JOB") == 0) ||
1640 	    (strcmp(ep, "ACCT") == 0))
1641 		return(1);
1642 	return(0);
1643 }
1644 
1645 void
1646 env_opt_end(int emptyok)
1647 {
1648 	int len;
1649 
1650 	if (opt_replyp + 2 > opt_replyend)
1651 		return;
1652 	len = opt_replyp + 2 - opt_reply;
1653 	if (emptyok || len > 6) {
1654 		*opt_replyp++ = IAC;
1655 		*opt_replyp++ = SE;
1656 		if (NETROOM() > len) {
1657 			ring_supply_data(&netoring, opt_reply, len);
1658 			printsub('>', &opt_reply[2], len - 2);
1659 		}
1660 /*@*/		else printf("slc_end_reply: not enough room\n");
1661 	}
1662 	if (opt_reply) {
1663 		free(opt_reply);
1664 		opt_reply = opt_replyp = opt_replyend = NULL;
1665 	}
1666 }
1667 
1668 
1669 
1670 int
1671 telrcv(void)
1672 {
1673     int c;
1674     int scc;
1675     unsigned char *sbp;
1676     int count;
1677     int returnValue = 0;
1678 
1679     scc = 0;
1680     count = 0;
1681     while (TTYROOM() > 2) {
1682 	if (scc == 0) {
1683 	    if (count) {
1684 		ring_consumed(&netiring, count);
1685 		returnValue = 1;
1686 		count = 0;
1687 	    }
1688 	    sbp = netiring.consume;
1689 	    scc = ring_full_consecutive(&netiring);
1690 	    if (scc == 0) {
1691 		/* No more data coming in */
1692 		break;
1693 	    }
1694 	}
1695 
1696 	c = *sbp++ & 0xff, scc--; count++;
1697 #ifdef	ENCRYPTION
1698 	if (decrypt_input)
1699 		c = (*decrypt_input)(c);
1700 #endif	/* ENCRYPTION */
1701 
1702 	switch (telrcv_state) {
1703 
1704 	case TS_CR:
1705 	    telrcv_state = TS_DATA;
1706 	    if (c == '\0') {
1707 		break;	/* Ignore \0 after CR */
1708 	    }
1709 	    else if ((c == '\n') && my_want_state_is_dont(TELOPT_ECHO) && !crmod) {
1710 		TTYADD(c);
1711 		break;
1712 	    }
1713 	    /* FALLTHROUGH */
1714 
1715 	case TS_DATA:
1716 	    if (c == IAC && telnetport >= 0) {
1717 		telrcv_state = TS_IAC;
1718 		break;
1719 	    }
1720 		    /*
1721 		     * The 'crmod' hack (see following) is needed
1722 		     * since we can't * set CRMOD on output only.
1723 		     * Machines like MULTICS like to send \r without
1724 		     * \n; since we must turn off CRMOD to get proper
1725 		     * input, the mapping is done here (sigh).
1726 		     */
1727 	    if ((c == '\r') && my_want_state_is_dont(TELOPT_BINARY)) {
1728 		if (scc > 0) {
1729 		    c = *sbp&0xff;
1730 #ifdef	ENCRYPTION
1731 		    if (decrypt_input)
1732 			c = (*decrypt_input)(c);
1733 #endif	/* ENCRYPTION */
1734 		    if (c == 0) {
1735 			sbp++, scc--; count++;
1736 			/* a "true" CR */
1737 			TTYADD('\r');
1738 		    } else if (my_want_state_is_dont(TELOPT_ECHO) &&
1739 					(c == '\n')) {
1740 			sbp++, scc--; count++;
1741 			TTYADD('\n');
1742 		    } else {
1743 #ifdef	ENCRYPTION
1744 			if (decrypt_input)
1745 			    (*decrypt_input)(-1);
1746 #endif	/* ENCRYPTION */
1747 
1748 			TTYADD('\r');
1749 			if (crmod) {
1750 				TTYADD('\n');
1751 			}
1752 		    }
1753 		} else {
1754 		    telrcv_state = TS_CR;
1755 		    TTYADD('\r');
1756 		    if (crmod) {
1757 			    TTYADD('\n');
1758 		    }
1759 		}
1760 	    } else {
1761 		TTYADD(c);
1762 	    }
1763 	    continue;
1764 
1765 	case TS_IAC:
1766 process_iac:
1767 	    switch (c) {
1768 
1769 	    case WILL:
1770 		telrcv_state = TS_WILL;
1771 		continue;
1772 
1773 	    case WONT:
1774 		telrcv_state = TS_WONT;
1775 		continue;
1776 
1777 	    case DO:
1778 		telrcv_state = TS_DO;
1779 		continue;
1780 
1781 	    case DONT:
1782 		telrcv_state = TS_DONT;
1783 		continue;
1784 
1785 	    case DM:
1786 		    /*
1787 		     * We may have missed an urgent notification,
1788 		     * so make sure we flush whatever is in the
1789 		     * buffer currently.
1790 		     */
1791 		printoption("RCVD", IAC, DM);
1792 		SYNCHing = 1;
1793 		(void) ttyflush(1);
1794 		SYNCHing = stilloob();
1795 		settimer(gotDM);
1796 		break;
1797 
1798 	    case SB:
1799 		SB_CLEAR();
1800 		telrcv_state = TS_SB;
1801 		continue;
1802 
1803 	    case IAC:
1804 		TTYADD(IAC);
1805 		break;
1806 
1807 	    case NOP:
1808 	    case GA:
1809 	    default:
1810 		printoption("RCVD", IAC, c);
1811 		break;
1812 	    }
1813 	    telrcv_state = TS_DATA;
1814 	    continue;
1815 
1816 	case TS_WILL:
1817 	    printoption("RCVD", WILL, c);
1818 	    willoption(c);
1819 	    telrcv_state = TS_DATA;
1820 	    continue;
1821 
1822 	case TS_WONT:
1823 	    printoption("RCVD", WONT, c);
1824 	    wontoption(c);
1825 	    telrcv_state = TS_DATA;
1826 	    continue;
1827 
1828 	case TS_DO:
1829 	    printoption("RCVD", DO, c);
1830 	    dooption(c);
1831 	    if (c == TELOPT_NAWS) {
1832 		sendnaws();
1833 	    } else if (c == TELOPT_LFLOW) {
1834 		localflow = 1;
1835 		setcommandmode();
1836 		setconnmode(0);
1837 	    }
1838 	    telrcv_state = TS_DATA;
1839 	    continue;
1840 
1841 	case TS_DONT:
1842 	    printoption("RCVD", DONT, c);
1843 	    dontoption(c);
1844 	    flushline = 1;
1845 	    setconnmode(0);	/* set new tty mode (maybe) */
1846 	    telrcv_state = TS_DATA;
1847 	    continue;
1848 
1849 	case TS_SB:
1850 	    if (c == IAC) {
1851 		telrcv_state = TS_SE;
1852 	    } else {
1853 		SB_ACCUM(c);
1854 	    }
1855 	    continue;
1856 
1857 	case TS_SE:
1858 	    if (c != SE) {
1859 		if (c != IAC) {
1860 		    /*
1861 		     * This is an error.  We only expect to get
1862 		     * "IAC IAC" or "IAC SE".  Several things may
1863 		     * have happend.  An IAC was not doubled, the
1864 		     * IAC SE was left off, or another option got
1865 		     * inserted into the suboption are all possibilities.
1866 		     * If we assume that the IAC was not doubled,
1867 		     * and really the IAC SE was left off, we could
1868 		     * get into an infinate loop here.  So, instead,
1869 		     * we terminate the suboption, and process the
1870 		     * partial suboption if we can.
1871 		     */
1872 		    SB_ACCUM(IAC);
1873 		    SB_ACCUM(c);
1874 		    subpointer -= 2;
1875 		    SB_TERM();
1876 
1877 		    printoption("In SUBOPTION processing, RCVD", IAC, c);
1878 		    suboption();	/* handle sub-option */
1879 		    telrcv_state = TS_IAC;
1880 		    goto process_iac;
1881 		}
1882 		SB_ACCUM(c);
1883 		telrcv_state = TS_SB;
1884 	    } else {
1885 		SB_ACCUM(IAC);
1886 		SB_ACCUM(SE);
1887 		subpointer -= 2;
1888 		SB_TERM();
1889 		suboption();	/* handle sub-option */
1890 		telrcv_state = TS_DATA;
1891 	    }
1892 	}
1893     }
1894     if (count)
1895 	ring_consumed(&netiring, count);
1896     return returnValue||count;
1897 }
1898 
1899 static int bol = 1, local = 0;
1900 
1901 int
1902 rlogin_susp(void)
1903 {
1904     if (local) {
1905 	local = 0;
1906 	bol = 1;
1907 	command(0, "z\n", 2);
1908 	return(1);
1909     }
1910     return(0);
1911 }
1912 
1913 static int
1914 telsnd(void)
1915 {
1916     int tcc;
1917     int count;
1918     int returnValue = 0;
1919     unsigned char *tbp;
1920 
1921     tcc = 0;
1922     count = 0;
1923     while (NETROOM() > 2) {
1924 	int sc;
1925 	int c;
1926 
1927 	if (tcc == 0) {
1928 	    if (count) {
1929 		ring_consumed(&ttyiring, count);
1930 		returnValue = 1;
1931 		count = 0;
1932 	    }
1933 	    tbp = ttyiring.consume;
1934 	    tcc = ring_full_consecutive(&ttyiring);
1935 	    if (tcc == 0) {
1936 		break;
1937 	    }
1938 	}
1939 	c = *tbp++ & 0xff, sc = strip(c), tcc--; count++;
1940 	if (rlogin != _POSIX_VDISABLE) {
1941 		if (bol) {
1942 			bol = 0;
1943 			if (sc == rlogin) {
1944 				local = 1;
1945 				continue;
1946 			}
1947 		} else if (local) {
1948 			local = 0;
1949 			if (sc == '.' || c == termEofChar) {
1950 				bol = 1;
1951 				command(0, "close\n", 6);
1952 				continue;
1953 			}
1954 			if (sc == termSuspChar) {
1955 				bol = 1;
1956 				command(0, "z\n", 2);
1957 				continue;
1958 			}
1959 			if (sc == escape) {
1960 				command(0, tbp, tcc);
1961 				bol = 1;
1962 				count += tcc;
1963 				tcc = 0;
1964 				flushline = 1;
1965 				break;
1966 			}
1967 			if (sc != rlogin) {
1968 				++tcc;
1969 				--tbp;
1970 				--count;
1971 				c = sc = rlogin;
1972 			}
1973 		}
1974 		if ((sc == '\n') || (sc == '\r'))
1975 			bol = 1;
1976 	} else if (escape != _POSIX_VDISABLE && sc == escape) {
1977 	    /*
1978 	     * Double escape is a pass through of a single escape character.
1979 	     */
1980 	    if (tcc && strip(*tbp) == escape) {
1981 		tbp++;
1982 		tcc--;
1983 		count++;
1984 		bol = 0;
1985 	    } else {
1986 		command(0, (char *)tbp, tcc);
1987 		bol = 1;
1988 		count += tcc;
1989 		tcc = 0;
1990 		flushline = 1;
1991 		break;
1992 	    }
1993 	} else
1994 	    bol = 0;
1995 #ifdef	KLUDGELINEMODE
1996 	if (kludgelinemode && (globalmode&MODE_EDIT) && (sc == echoc)) {
1997 	    if (tcc > 0 && strip(*tbp) == echoc) {
1998 		tcc--; tbp++; count++;
1999 	    } else {
2000 		dontlecho = !dontlecho;
2001 		settimer(echotoggle);
2002 		setconnmode(0);
2003 		flushline = 1;
2004 		break;
2005 	    }
2006 	}
2007 #endif
2008 	if (MODE_LOCAL_CHARS(globalmode)) {
2009 	    if (TerminalSpecialChars(sc) == 0) {
2010 		bol = 1;
2011 		break;
2012 	    }
2013 	}
2014 	if (my_want_state_is_wont(TELOPT_BINARY)) {
2015 	    switch (c) {
2016 	    case '\n':
2017 		    /*
2018 		     * If we are in CRMOD mode (\r ==> \n)
2019 		     * on our local machine, then probably
2020 		     * a newline (unix) is CRLF (TELNET).
2021 		     */
2022 		if (MODE_LOCAL_CHARS(globalmode)) {
2023 		    NETADD('\r');
2024 		}
2025 		NETADD('\n');
2026 		bol = flushline = 1;
2027 		break;
2028 	    case '\r':
2029 		if (!crlf) {
2030 		    NET2ADD('\r', '\0');
2031 		} else {
2032 		    NET2ADD('\r', '\n');
2033 		}
2034 		bol = flushline = 1;
2035 		break;
2036 	    case IAC:
2037 		NET2ADD(IAC, IAC);
2038 		break;
2039 	    default:
2040 		NETADD(c);
2041 		break;
2042 	    }
2043 	} else if (c == IAC) {
2044 	    NET2ADD(IAC, IAC);
2045 	} else {
2046 	    NETADD(c);
2047 	}
2048     }
2049     if (count)
2050 	ring_consumed(&ttyiring, count);
2051     return returnValue||count;		/* Non-zero if we did anything */
2052 }
2053 
2054 /*
2055  * Scheduler()
2056  *
2057  * Try to do something.
2058  *
2059  * If we do something useful, return 1; else return 0.
2060  *
2061  */
2062 
2063 static int
2064 Scheduler(int block)
2065 {
2066 		/* One wants to be a bit careful about setting returnValue
2067 		 * to one, since a one implies we did some useful work,
2068 		 * and therefore probably won't be called to block next
2069 		 */
2070     int returnValue;
2071     int netin, netout, netex, ttyin, ttyout;
2072 
2073     /* Decide which rings should be processed */
2074 
2075     netout = ring_full_count(&netoring) &&
2076 	    (flushline ||
2077 		(my_want_state_is_wont(TELOPT_LINEMODE)
2078 #ifdef	KLUDGELINEMODE
2079 			&& (!kludgelinemode || my_want_state_is_do(TELOPT_SGA))
2080 #endif
2081 		) ||
2082 			my_want_state_is_will(TELOPT_BINARY));
2083     ttyout = ring_full_count(&ttyoring);
2084 
2085     ttyin = ring_empty_count(&ttyiring) && (clienteof == 0);
2086 
2087     netin = !ISend && ring_empty_count(&netiring);
2088 
2089     netex = !SYNCHing;
2090 
2091     /* Call to system code to process rings */
2092 
2093     returnValue = process_rings(netin, netout, netex, ttyin, ttyout, !block);
2094 
2095     /* Now, look at the input rings, looking for work to do. */
2096 
2097     if (ring_full_count(&ttyiring)) {
2098 	    returnValue |= telsnd();
2099     }
2100 
2101     if (ring_full_count(&netiring)) {
2102 	returnValue |= telrcv();
2103     }
2104     return returnValue;
2105 }
2106 
2107 #ifdef	AUTHENTICATION
2108 #define __unusedhere
2109 #else
2110 #define __unusedhere __unused
2111 #endif
2112 /*
2113  * Select from tty and network...
2114  */
2115 void
2116 telnet(char *user __unusedhere)
2117 {
2118     sys_telnet_init();
2119 
2120 #ifdef	AUTHENTICATION
2121 #ifdef	ENCRYPTION
2122     {
2123 	static char local_host[256] = { 0 };
2124 
2125 	if (!local_host[0]) {
2126 		gethostname(local_host, sizeof(local_host));
2127 		local_host[sizeof(local_host)-1] = 0;
2128 	}
2129 	auth_encrypt_init(local_host, hostname, "TELNET", 0);
2130 	auth_encrypt_user(user);
2131     }
2132 #endif
2133 #endif
2134     if (telnetport > 0) {
2135 #ifdef	AUTHENTICATION
2136 	if (autologin)
2137 		send_will(TELOPT_AUTHENTICATION, 1);
2138 #endif
2139 #ifdef	ENCRYPTION
2140 	send_do(TELOPT_ENCRYPT, 1);
2141 	send_will(TELOPT_ENCRYPT, 1);
2142 #endif	/* ENCRYPTION */
2143 	send_do(TELOPT_SGA, 1);
2144 	send_will(TELOPT_TTYPE, 1);
2145 	send_will(TELOPT_NAWS, 1);
2146 	send_will(TELOPT_TSPEED, 1);
2147 	send_will(TELOPT_LFLOW, 1);
2148 	send_will(TELOPT_LINEMODE, 1);
2149 	send_will(TELOPT_NEW_ENVIRON, 1);
2150 	send_do(TELOPT_STATUS, 1);
2151 	if (env_getvalue("DISPLAY"))
2152 	    send_will(TELOPT_XDISPLOC, 1);
2153 	if (eight)
2154 	    tel_enter_binary(eight);
2155     }
2156 
2157     for (;;) {
2158 	int schedValue;
2159 
2160 	while ((schedValue = Scheduler(0)) != 0) {
2161 	    if (schedValue == -1) {
2162 		setcommandmode();
2163 		return;
2164 	    }
2165 	}
2166 
2167 	if (Scheduler(1) == -1) {
2168 	    setcommandmode();
2169 	    return;
2170 	}
2171     }
2172 }
2173 
2174 #if	0	/* XXX - this not being in is a bug */
2175 /*
2176  * nextitem()
2177  *
2178  *	Return the address of the next "item" in the TELNET data
2179  * stream.  This will be the address of the next character if
2180  * the current address is a user data character, or it will
2181  * be the address of the character following the TELNET command
2182  * if the current address is a TELNET IAC ("I Am a Command")
2183  * character.
2184  */
2185 
2186 static char *
2187 nextitem(char *current)
2188 {
2189     if ((*current&0xff) != IAC) {
2190 	return current+1;
2191     }
2192     switch (*(current+1)&0xff) {
2193     case DO:
2194     case DONT:
2195     case WILL:
2196     case WONT:
2197 	return current+3;
2198     case SB:		/* loop forever looking for the SE */
2199 	{
2200 	    char *look = current+2;
2201 
2202 	    for (;;) {
2203 		if ((*look++&0xff) == IAC) {
2204 		    if ((*look++&0xff) == SE) {
2205 			return look;
2206 		    }
2207 		}
2208 	    }
2209 	}
2210     default:
2211 	return current+2;
2212     }
2213 }
2214 #endif	/* 0 */
2215 
2216 /*
2217  * netclear()
2218  *
2219  *	We are about to do a TELNET SYNCH operation.  Clear
2220  * the path to the network.
2221  *
2222  *	Things are a bit tricky since we may have sent the first
2223  * byte or so of a previous TELNET command into the network.
2224  * So, we have to scan the network buffer from the beginning
2225  * until we are up to where we want to be.
2226  *
2227  *	A side effect of what we do, just to keep things
2228  * simple, is to clear the urgent data pointer.  The principal
2229  * caller should be setting the urgent data pointer AFTER calling
2230  * us in any case.
2231  */
2232 
2233 static void
2234 netclear(void)
2235 {
2236 	/* Deleted */
2237 }
2238 
2239 /*
2240  * These routines add various telnet commands to the data stream.
2241  */
2242 
2243 static void
2244 doflush(void)
2245 {
2246     NET2ADD(IAC, DO);
2247     NETADD(TELOPT_TM);
2248     flushline = 1;
2249     flushout = 1;
2250     (void) ttyflush(1);			/* Flush/drop output */
2251     /* do printoption AFTER flush, otherwise the output gets tossed... */
2252     printoption("SENT", DO, TELOPT_TM);
2253 }
2254 
2255 void
2256 xmitAO(void)
2257 {
2258     NET2ADD(IAC, AO);
2259     printoption("SENT", IAC, AO);
2260     if (autoflush) {
2261 	doflush();
2262     }
2263 }
2264 
2265 void
2266 xmitEL(void)
2267 {
2268     NET2ADD(IAC, EL);
2269     printoption("SENT", IAC, EL);
2270 }
2271 
2272 void
2273 xmitEC(void)
2274 {
2275     NET2ADD(IAC, EC);
2276     printoption("SENT", IAC, EC);
2277 }
2278 
2279 int
2280 dosynch(char *ch __unused)
2281 {
2282     netclear();			/* clear the path to the network */
2283     NETADD(IAC);
2284     setneturg();
2285     NETADD(DM);
2286     printoption("SENT", IAC, DM);
2287     return 1;
2288 }
2289 
2290 int want_status_response = 0;
2291 
2292 int
2293 get_status(char *ch __unused)
2294 {
2295     unsigned char tmp[16];
2296     unsigned char *cp;
2297 
2298     if (my_want_state_is_dont(TELOPT_STATUS)) {
2299 	printf("Remote side does not support STATUS option\n");
2300 	return 0;
2301     }
2302     cp = tmp;
2303 
2304     *cp++ = IAC;
2305     *cp++ = SB;
2306     *cp++ = TELOPT_STATUS;
2307     *cp++ = TELQUAL_SEND;
2308     *cp++ = IAC;
2309     *cp++ = SE;
2310     if (NETROOM() >= cp - tmp) {
2311 	ring_supply_data(&netoring, tmp, cp-tmp);
2312 	printsub('>', tmp+2, cp - tmp - 2);
2313     }
2314     ++want_status_response;
2315     return 1;
2316 }
2317 
2318 void
2319 intp(void)
2320 {
2321     NET2ADD(IAC, IP);
2322     printoption("SENT", IAC, IP);
2323     flushline = 1;
2324     if (autoflush) {
2325 	doflush();
2326     }
2327     if (autosynch) {
2328 	dosynch(NULL);
2329     }
2330 }
2331 
2332 void
2333 sendbrk(void)
2334 {
2335     NET2ADD(IAC, BREAK);
2336     printoption("SENT", IAC, BREAK);
2337     flushline = 1;
2338     if (autoflush) {
2339 	doflush();
2340     }
2341     if (autosynch) {
2342 	dosynch(NULL);
2343     }
2344 }
2345 
2346 void
2347 sendabort(void)
2348 {
2349     NET2ADD(IAC, ABORT);
2350     printoption("SENT", IAC, ABORT);
2351     flushline = 1;
2352     if (autoflush) {
2353 	doflush();
2354     }
2355     if (autosynch) {
2356 	dosynch(NULL);
2357     }
2358 }
2359 
2360 void
2361 sendsusp(void)
2362 {
2363     NET2ADD(IAC, SUSP);
2364     printoption("SENT", IAC, SUSP);
2365     flushline = 1;
2366     if (autoflush) {
2367 	doflush();
2368     }
2369     if (autosynch) {
2370 	dosynch(NULL);
2371     }
2372 }
2373 
2374 void
2375 sendeof(void)
2376 {
2377     NET2ADD(IAC, xEOF);
2378     printoption("SENT", IAC, xEOF);
2379 }
2380 
2381 void
2382 sendayt(void)
2383 {
2384     NET2ADD(IAC, AYT);
2385     printoption("SENT", IAC, AYT);
2386 }
2387 
2388 /*
2389  * Send a window size update to the remote system.
2390  */
2391 
2392 void
2393 sendnaws(void)
2394 {
2395     long rows, cols;
2396     unsigned char tmp[16];
2397     unsigned char *cp;
2398 
2399     if (my_state_is_wont(TELOPT_NAWS))
2400 	return;
2401 
2402 #define	PUTSHORT(cp, x) { if ((*cp++ = ((x)>>8)&0xff) == IAC) *cp++ = IAC; \
2403 			    if ((*cp++ = ((x))&0xff) == IAC) *cp++ = IAC; }
2404 
2405     if (TerminalWindowSize(&rows, &cols) == 0) {	/* Failed */
2406 	return;
2407     }
2408 
2409     cp = tmp;
2410 
2411     *cp++ = IAC;
2412     *cp++ = SB;
2413     *cp++ = TELOPT_NAWS;
2414     PUTSHORT(cp, cols);
2415     PUTSHORT(cp, rows);
2416     *cp++ = IAC;
2417     *cp++ = SE;
2418     if (NETROOM() >= cp - tmp) {
2419 	ring_supply_data(&netoring, tmp, cp-tmp);
2420 	printsub('>', tmp+2, cp - tmp - 2);
2421     }
2422 }
2423 
2424 void
2425 tel_enter_binary(int rw)
2426 {
2427     if (rw&1)
2428 	send_do(TELOPT_BINARY, 1);
2429     if (rw&2)
2430 	send_will(TELOPT_BINARY, 1);
2431 }
2432 
2433 void
2434 tel_leave_binary(int rw)
2435 {
2436     if (rw&1)
2437 	send_dont(TELOPT_BINARY, 1);
2438     if (rw&2)
2439 	send_wont(TELOPT_BINARY, 1);
2440 }
2441