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/crypto/heimdal/appl/telnet/telnetd/state.c

https://bitbucket.org/freebsd/freebsd-head/
C | 1360 lines | 902 code | 157 blank | 301 comment | 201 complexity | f74bbf320d31ef83ced582133f273fa5 MD5 | raw file
   1/*
   2 * Copyright (c) 1989, 1993
   3 *	The Regents of the University of California.  All rights reserved.
   4 *
   5 * Redistribution and use in source and binary forms, with or without
   6 * modification, are permitted provided that the following conditions
   7 * are met:
   8 * 1. Redistributions of source code must retain the above copyright
   9 *    notice, this list of conditions and the following disclaimer.
  10 * 2. Redistributions in binary form must reproduce the above copyright
  11 *    notice, this list of conditions and the following disclaimer in the
  12 *    documentation and/or other materials provided with the distribution.
  13 * 3. All advertising materials mentioning features or use of this software
  14 *    must display the following acknowledgement:
  15 *	This product includes software developed by the University of
  16 *	California, Berkeley and its contributors.
  17 * 4. Neither the name of the University nor the names of its contributors
  18 *    may be used to endorse or promote products derived from this software
  19 *    without specific prior written permission.
  20 *
  21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31 * SUCH DAMAGE.
  32 */
  33
  34#include "telnetd.h"
  35
  36RCSID("$Id$");
  37
  38unsigned char	doopt[] = { IAC, DO, '%', 'c', 0 };
  39unsigned char	dont[] = { IAC, DONT, '%', 'c', 0 };
  40unsigned char	will[] = { IAC, WILL, '%', 'c', 0 };
  41unsigned char	wont[] = { IAC, WONT, '%', 'c', 0 };
  42int	not42 = 1;
  43
  44/*
  45 * Buffer for sub-options, and macros
  46 * for suboptions buffer manipulations
  47 */
  48unsigned char subbuffer[1024*64], *subpointer= subbuffer, *subend= subbuffer;
  49
  50#define	SB_CLEAR()	subpointer = subbuffer
  51#define	SB_TERM()	{ subend = subpointer; SB_CLEAR(); }
  52#define	SB_ACCUM(c)	if (subpointer < (subbuffer+sizeof subbuffer)) { \
  53    *subpointer++ = (c); \
  54			     }
  55#define	SB_GET()	((*subpointer++)&0xff)
  56#define	SB_EOF()	(subpointer >= subend)
  57#define	SB_LEN()	(subend - subpointer)
  58
  59#ifdef	ENV_HACK
  60unsigned char *subsave;
  61#define SB_SAVE()	subsave = subpointer;
  62#define	SB_RESTORE()	subpointer = subsave;
  63#endif
  64
  65
  66/*
  67 * State for recv fsm
  68 */
  69#define	TS_DATA		0	/* base state */
  70#define	TS_IAC		1	/* look for double IAC's */
  71#define	TS_CR		2	/* CR-LF ->'s CR */
  72#define	TS_SB		3	/* throw away begin's... */
  73#define	TS_SE		4	/* ...end's (suboption negotiation) */
  74#define	TS_WILL		5	/* will option negotiation */
  75#define	TS_WONT		6	/* wont -''- */
  76#define	TS_DO		7	/* do -''- */
  77#define	TS_DONT		8	/* dont -''- */
  78
  79void
  80telrcv(void)
  81{
  82    int c;
  83    static int state = TS_DATA;
  84
  85    while (ncc > 0) {
  86	if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
  87	    break;
  88	c = *netip++ & 0377, ncc--;
  89#ifdef ENCRYPTION
  90	if (decrypt_input)
  91	    c = (*decrypt_input)(c);
  92#endif
  93	switch (state) {
  94
  95	case TS_CR:
  96	    state = TS_DATA;
  97	    /* Strip off \n or \0 after a \r */
  98	    if ((c == 0) || (c == '\n')) {
  99		break;
 100	    }
 101	    /* FALL THROUGH */
 102
 103	case TS_DATA:
 104	    if (c == IAC) {
 105		state = TS_IAC;
 106		break;
 107	    }
 108	    /*
 109	     * We now map \r\n ==> \r for pragmatic reasons.
 110	     * Many client implementations send \r\n when
 111	     * the user hits the CarriageReturn key.
 112	     *
 113	     * We USED to map \r\n ==> \n, since \r\n says
 114	     * that we want to be in column 1 of the next
 115	     * printable line, and \n is the standard
 116	     * unix way of saying that (\r is only good
 117	     * if CRMOD is set, which it normally is).
 118	     */
 119	    if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
 120		int nc = *netip;
 121#ifdef ENCRYPTION
 122		if (decrypt_input)
 123		    nc = (*decrypt_input)(nc & 0xff);
 124#endif
 125		{
 126#ifdef ENCRYPTION
 127		    if (decrypt_input)
 128			(void)(*decrypt_input)(-1);
 129#endif
 130		    state = TS_CR;
 131		}
 132	    }
 133	    *pfrontp++ = c;
 134	    break;
 135
 136	case TS_IAC:
 137	gotiac:			switch (c) {
 138
 139	    /*
 140	     * Send the process on the pty side an
 141	     * interrupt.  Do this with a NULL or
 142	     * interrupt char; depending on the tty mode.
 143	     */
 144	case IP:
 145	    DIAG(TD_OPTIONS,
 146		 printoption("td: recv IAC", c));
 147	    interrupt();
 148	    break;
 149
 150	case BREAK:
 151	    DIAG(TD_OPTIONS,
 152		 printoption("td: recv IAC", c));
 153	    sendbrk();
 154	    break;
 155
 156	    /*
 157	     * Are You There?
 158	     */
 159	case AYT:
 160	    DIAG(TD_OPTIONS,
 161		 printoption("td: recv IAC", c));
 162	    recv_ayt();
 163	    break;
 164
 165	    /*
 166	     * Abort Output
 167	     */
 168	case AO:
 169	    {
 170		DIAG(TD_OPTIONS,
 171		     printoption("td: recv IAC", c));
 172		ptyflush();	/* half-hearted */
 173		init_termbuf();
 174
 175		if (slctab[SLC_AO].sptr &&
 176		    *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
 177		    *pfrontp++ =
 178			(unsigned char)*slctab[SLC_AO].sptr;
 179		}
 180
 181		netclear();	/* clear buffer back */
 182		output_data ("%c%c", IAC, DM);
 183		neturg = nfrontp-1; /* off by one XXX */
 184		DIAG(TD_OPTIONS,
 185		     printoption("td: send IAC", DM));
 186		break;
 187	    }
 188
 189	/*
 190	 * Erase Character and
 191	 * Erase Line
 192	 */
 193	case EC:
 194	case EL:
 195	    {
 196		cc_t ch;
 197
 198		DIAG(TD_OPTIONS,
 199		     printoption("td: recv IAC", c));
 200		ptyflush();	/* half-hearted */
 201		init_termbuf();
 202		if (c == EC)
 203		    ch = *slctab[SLC_EC].sptr;
 204		else
 205		    ch = *slctab[SLC_EL].sptr;
 206		if (ch != (cc_t)(_POSIX_VDISABLE))
 207		    *pfrontp++ = (unsigned char)ch;
 208		break;
 209	    }
 210
 211	/*
 212	 * Check for urgent data...
 213	 */
 214	case DM:
 215	    DIAG(TD_OPTIONS,
 216		 printoption("td: recv IAC", c));
 217	    SYNCHing = stilloob(net);
 218	    settimer(gotDM);
 219	    break;
 220
 221
 222	    /*
 223	     * Begin option subnegotiation...
 224	     */
 225	case SB:
 226	    state = TS_SB;
 227	    SB_CLEAR();
 228	    continue;
 229
 230	case WILL:
 231	    state = TS_WILL;
 232	    continue;
 233
 234	case WONT:
 235	    state = TS_WONT;
 236	    continue;
 237
 238	case DO:
 239	    state = TS_DO;
 240	    continue;
 241
 242	case DONT:
 243	    state = TS_DONT;
 244	    continue;
 245	case EOR:
 246	    if (his_state_is_will(TELOPT_EOR))
 247		doeof();
 248	    break;
 249
 250	    /*
 251	     * Handle RFC 10xx Telnet linemode option additions
 252	     * to command stream (EOF, SUSP, ABORT).
 253	     */
 254	case xEOF:
 255	    doeof();
 256	    break;
 257
 258	case SUSP:
 259	    sendsusp();
 260	    break;
 261
 262	case ABORT:
 263	    sendbrk();
 264	    break;
 265
 266	case IAC:
 267	    *pfrontp++ = c;
 268	    break;
 269	}
 270	state = TS_DATA;
 271	break;
 272
 273	case TS_SB:
 274	    if (c == IAC) {
 275		state = TS_SE;
 276	    } else {
 277		SB_ACCUM(c);
 278	    }
 279	    break;
 280
 281	case TS_SE:
 282	    if (c != SE) {
 283		if (c != IAC) {
 284		    /*
 285		     * bad form of suboption negotiation.
 286		     * handle it in such a way as to avoid
 287		     * damage to local state.  Parse
 288		     * suboption buffer found so far,
 289		     * then treat remaining stream as
 290		     * another command sequence.
 291		     */
 292
 293		    /* for DIAGNOSTICS */
 294		    SB_ACCUM(IAC);
 295		    SB_ACCUM(c);
 296		    subpointer -= 2;
 297
 298		    SB_TERM();
 299		    suboption();
 300		    state = TS_IAC;
 301		    goto gotiac;
 302		}
 303		SB_ACCUM(c);
 304		state = TS_SB;
 305	    } else {
 306		/* for DIAGNOSTICS */
 307		SB_ACCUM(IAC);
 308		SB_ACCUM(SE);
 309		subpointer -= 2;
 310
 311		SB_TERM();
 312		suboption();	/* handle sub-option */
 313		state = TS_DATA;
 314	    }
 315	    break;
 316
 317	case TS_WILL:
 318	    willoption(c);
 319	    state = TS_DATA;
 320	    continue;
 321
 322	case TS_WONT:
 323	    wontoption(c);
 324	    if (c==TELOPT_ENCRYPT && his_do_dont_is_changing(TELOPT_ENCRYPT) )
 325                dontoption(c);
 326	    state = TS_DATA;
 327	    continue;
 328
 329	case TS_DO:
 330	    dooption(c);
 331	    state = TS_DATA;
 332	    continue;
 333
 334	case TS_DONT:
 335	    dontoption(c);
 336	    state = TS_DATA;
 337	    continue;
 338
 339	default:
 340	    syslog(LOG_ERR, "telnetd: panic state=%d\n", state);
 341	    printf("telnetd: panic state=%d\n", state);
 342	    exit(1);
 343	}
 344    }
 345}  /* end of telrcv */
 346
 347/*
 348 * The will/wont/do/dont state machines are based on Dave Borman's
 349 * Telnet option processing state machine.
 350 *
 351 * These correspond to the following states:
 352 *	my_state = the last negotiated state
 353 *	want_state = what I want the state to go to
 354 *	want_resp = how many requests I have sent
 355 * All state defaults are negative, and resp defaults to 0.
 356 *
 357 * When initiating a request to change state to new_state:
 358 *
 359 * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
 360 *	do nothing;
 361 * } else {
 362 *	want_state = new_state;
 363 *	send new_state;
 364 *	want_resp++;
 365 * }
 366 *
 367 * When receiving new_state:
 368 *
 369 * if (want_resp) {
 370 *	want_resp--;
 371 *	if (want_resp && (new_state == my_state))
 372 *		want_resp--;
 373 * }
 374 * if ((want_resp == 0) && (new_state != want_state)) {
 375 *	if (ok_to_switch_to new_state)
 376 *		want_state = new_state;
 377 *	else
 378 *		want_resp++;
 379 *	send want_state;
 380 * }
 381 * my_state = new_state;
 382 *
 383 * Note that new_state is implied in these functions by the function itself.
 384 * will and do imply positive new_state, wont and dont imply negative.
 385 *
 386 * Finally, there is one catch.  If we send a negative response to a
 387 * positive request, my_state will be the positive while want_state will
 388 * remain negative.  my_state will revert to negative when the negative
 389 * acknowlegment arrives from the peer.  Thus, my_state generally tells
 390 * us not only the last negotiated state, but also tells us what the peer
 391 * wants to be doing as well.  It is important to understand this difference
 392 * as we may wish to be processing data streams based on our desired state
 393 * (want_state) or based on what the peer thinks the state is (my_state).
 394 *
 395 * This all works fine because if the peer sends a positive request, the data
 396 * that we receive prior to negative acknowlegment will probably be affected
 397 * by the positive state, and we can process it as such (if we can; if we
 398 * can't then it really doesn't matter).  If it is that important, then the
 399 * peer probably should be buffering until this option state negotiation
 400 * is complete.
 401 *
 402 */
 403void
 404send_do(int option, int init)
 405{
 406    if (init) {
 407	if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
 408	    his_want_state_is_will(option))
 409	    return;
 410	/*
 411	 * Special case for TELOPT_TM:  We send a DO, but pretend
 412	 * that we sent a DONT, so that we can send more DOs if
 413	 * we want to.
 414	 */
 415	if (option == TELOPT_TM)
 416	    set_his_want_state_wont(option);
 417	else
 418	    set_his_want_state_will(option);
 419	do_dont_resp[option]++;
 420    }
 421    output_data((const char *)doopt, option);
 422
 423    DIAG(TD_OPTIONS, printoption("td: send do", option));
 424}
 425
 426#ifdef	AUTHENTICATION
 427extern void auth_request(void);
 428#endif
 429#ifdef	ENCRYPTION
 430extern void encrypt_send_support(void);
 431#endif
 432
 433void
 434willoption(int option)
 435{
 436    int changeok = 0;
 437    void (*func)(void) = NULL;
 438
 439    /*
 440     * process input from peer.
 441     */
 442
 443    DIAG(TD_OPTIONS, printoption("td: recv will", option));
 444
 445    if (do_dont_resp[option]) {
 446	do_dont_resp[option]--;
 447	if (do_dont_resp[option] && his_state_is_will(option))
 448	    do_dont_resp[option]--;
 449    }
 450    if (do_dont_resp[option] == 0) {
 451	if (his_want_state_is_wont(option)) {
 452	    switch (option) {
 453
 454	    case TELOPT_BINARY:
 455		init_termbuf();
 456		tty_binaryin(1);
 457		set_termbuf();
 458		changeok++;
 459		break;
 460
 461	    case TELOPT_ECHO:
 462		/*
 463		 * See comments below for more info.
 464		 */
 465		not42 = 0;	/* looks like a 4.2 system */
 466		break;
 467
 468	    case TELOPT_TM:
 469		/*
 470		 * We never respond to a WILL TM, and
 471		 * we leave the state WONT.
 472		 */
 473		return;
 474
 475	    case TELOPT_LFLOW:
 476		/*
 477		 * If we are going to support flow control
 478		 * option, then don't worry peer that we can't
 479		 * change the flow control characters.
 480		 */
 481		slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 482		slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
 483		slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 484		slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
 485	    case TELOPT_TTYPE:
 486	    case TELOPT_SGA:
 487	    case TELOPT_NAWS:
 488	    case TELOPT_TSPEED:
 489	    case TELOPT_XDISPLOC:
 490	    case TELOPT_NEW_ENVIRON:
 491	    case TELOPT_OLD_ENVIRON:
 492		changeok++;
 493		break;
 494
 495
 496#ifdef	AUTHENTICATION
 497	    case TELOPT_AUTHENTICATION:
 498		func = auth_request;
 499		changeok++;
 500		break;
 501#endif
 502
 503#ifdef	ENCRYPTION
 504	    case TELOPT_ENCRYPT:
 505		func = encrypt_send_support;
 506		changeok++;
 507		break;
 508#endif
 509
 510	    default:
 511		break;
 512	    }
 513	    if (changeok) {
 514		set_his_want_state_will(option);
 515		send_do(option, 0);
 516	    } else {
 517		do_dont_resp[option]++;
 518		send_dont(option, 0);
 519	    }
 520	} else {
 521	    /*
 522	     * Option processing that should happen when
 523	     * we receive conformation of a change in
 524	     * state that we had requested.
 525	     */
 526	    switch (option) {
 527	    case TELOPT_ECHO:
 528		not42 = 0;	/* looks like a 4.2 system */
 529		/*
 530		 * Egads, he responded "WILL ECHO".  Turn
 531		 * it off right now!
 532		 */
 533		send_dont(option, 1);
 534		/*
 535		 * "WILL ECHO".  Kludge upon kludge!
 536		 * A 4.2 client is now echoing user input at
 537		 * the tty.  This is probably undesireable and
 538		 * it should be stopped.  The client will
 539		 * respond WONT TM to the DO TM that we send to
 540		 * check for kludge linemode.  When the WONT TM
 541		 * arrives, linemode will be turned off and a
 542		 * change propogated to the pty.  This change
 543		 * will cause us to process the new pty state
 544		 * in localstat(), which will notice that
 545		 * linemode is off and send a WILL ECHO
 546		 * so that we are properly in character mode and
 547		 * all is well.
 548		 */
 549		break;
 550
 551#ifdef	AUTHENTICATION
 552	    case TELOPT_AUTHENTICATION:
 553		func = auth_request;
 554		break;
 555#endif
 556
 557#ifdef	ENCRYPTION
 558	    case TELOPT_ENCRYPT:
 559		func = encrypt_send_support;
 560		break;
 561#endif
 562
 563	    case TELOPT_LFLOW:
 564		func = flowstat;
 565		break;
 566	    }
 567	}
 568    }
 569    set_his_state_will(option);
 570    if (func)
 571	(*func)();
 572}  /* end of willoption */
 573
 574void
 575send_dont(int option, int init)
 576{
 577    if (init) {
 578	if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
 579	    his_want_state_is_wont(option))
 580	    return;
 581	set_his_want_state_wont(option);
 582	do_dont_resp[option]++;
 583    }
 584    output_data((const char *)dont, option);
 585
 586    DIAG(TD_OPTIONS, printoption("td: send dont", option));
 587}
 588
 589void
 590wontoption(int option)
 591{
 592    /*
 593     * Process client input.
 594	 */
 595
 596    DIAG(TD_OPTIONS, printoption("td: recv wont", option));
 597
 598    if (do_dont_resp[option]) {
 599	do_dont_resp[option]--;
 600	if (do_dont_resp[option] && his_state_is_wont(option))
 601	    do_dont_resp[option]--;
 602    }
 603    if (do_dont_resp[option] == 0) {
 604	if (his_want_state_is_will(option)) {
 605	    /* it is always ok to change to negative state */
 606	    switch (option) {
 607	    case TELOPT_ECHO:
 608		not42 = 1; /* doesn't seem to be a 4.2 system */
 609		break;
 610
 611	    case TELOPT_BINARY:
 612		init_termbuf();
 613		tty_binaryin(0);
 614		set_termbuf();
 615		break;
 616
 617	    case TELOPT_TM:
 618		/*
 619		 * If we get a WONT TM, and had sent a DO TM,
 620		 * don't respond with a DONT TM, just leave it
 621		 * as is.  Short circut the state machine to
 622		 * achive this.
 623		 */
 624		set_his_want_state_wont(TELOPT_TM);
 625		return;
 626
 627	    case TELOPT_LFLOW:
 628		/*
 629		 * If we are not going to support flow control
 630		 * option, then let peer know that we can't
 631		 * change the flow control characters.
 632		 */
 633		slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 634		slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
 635		slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 636		slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
 637		break;
 638
 639#ifdef AUTHENTICATION
 640	    case TELOPT_AUTHENTICATION:
 641		auth_finished(0, AUTH_REJECT);
 642		break;
 643#endif
 644
 645		/*
 646		 * For options that we might spin waiting for
 647		 * sub-negotiation, if the client turns off the
 648		 * option rather than responding to the request,
 649		 * we have to treat it here as if we got a response
 650		 * to the sub-negotiation, (by updating the timers)
 651		 * so that we'll break out of the loop.
 652		 */
 653	    case TELOPT_TTYPE:
 654		settimer(ttypesubopt);
 655		break;
 656
 657	    case TELOPT_TSPEED:
 658		settimer(tspeedsubopt);
 659		break;
 660
 661	    case TELOPT_XDISPLOC:
 662		settimer(xdisplocsubopt);
 663		break;
 664
 665	    case TELOPT_OLD_ENVIRON:
 666		settimer(oenvironsubopt);
 667		break;
 668
 669	    case TELOPT_NEW_ENVIRON:
 670		settimer(environsubopt);
 671		break;
 672
 673	    default:
 674		break;
 675	    }
 676	    set_his_want_state_wont(option);
 677	    if (his_state_is_will(option))
 678		send_dont(option, 0);
 679	} else {
 680	    switch (option) {
 681	    case TELOPT_TM:
 682		break;
 683
 684#ifdef AUTHENTICATION
 685	    case TELOPT_AUTHENTICATION:
 686		auth_finished(0, AUTH_REJECT);
 687		break;
 688#endif
 689	    default:
 690		break;
 691	    }
 692	}
 693    }
 694    set_his_state_wont(option);
 695
 696}  /* end of wontoption */
 697
 698void
 699send_will(int option, int init)
 700{
 701    if (init) {
 702	if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
 703	    my_want_state_is_will(option))
 704	    return;
 705	set_my_want_state_will(option);
 706	will_wont_resp[option]++;
 707    }
 708    output_data ((const char *)will, option);
 709
 710    DIAG(TD_OPTIONS, printoption("td: send will", option));
 711}
 712
 713/*
 714 * When we get a DONT SGA, we will try once to turn it
 715 * back on.  If the other side responds DONT SGA, we
 716 * leave it at that.  This is so that when we talk to
 717 * clients that understand KLUDGELINEMODE but not LINEMODE,
 718 * we'll keep them in char-at-a-time mode.
 719 */
 720int turn_on_sga = 0;
 721
 722void
 723dooption(int option)
 724{
 725    int changeok = 0;
 726
 727    /*
 728     * Process client input.
 729     */
 730
 731    DIAG(TD_OPTIONS, printoption("td: recv do", option));
 732
 733    if (will_wont_resp[option]) {
 734	will_wont_resp[option]--;
 735	if (will_wont_resp[option] && my_state_is_will(option))
 736	    will_wont_resp[option]--;
 737    }
 738    if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
 739	switch (option) {
 740	case TELOPT_ECHO:
 741	    {
 742		init_termbuf();
 743		tty_setecho(1);
 744		set_termbuf();
 745	    }
 746	changeok++;
 747	break;
 748
 749	case TELOPT_BINARY:
 750	    init_termbuf();
 751	    tty_binaryout(1);
 752	    set_termbuf();
 753	    changeok++;
 754	    break;
 755
 756	case TELOPT_SGA:
 757	    turn_on_sga = 0;
 758	    changeok++;
 759	    break;
 760
 761	case TELOPT_STATUS:
 762	    changeok++;
 763	    break;
 764
 765	case TELOPT_TM:
 766	    /*
 767	     * Special case for TM.  We send a WILL, but
 768	     * pretend we sent a WONT.
 769	     */
 770	    send_will(option, 0);
 771	    set_my_want_state_wont(option);
 772	    set_my_state_wont(option);
 773	    return;
 774
 775	case TELOPT_LOGOUT:
 776	    /*
 777	     * When we get a LOGOUT option, respond
 778	     * with a WILL LOGOUT, make sure that
 779	     * it gets written out to the network,
 780	     * and then just go away...
 781	     */
 782	    set_my_want_state_will(TELOPT_LOGOUT);
 783	    send_will(TELOPT_LOGOUT, 0);
 784	    set_my_state_will(TELOPT_LOGOUT);
 785	    netflush();
 786	    cleanup(0);
 787	    /* NOT REACHED */
 788	    break;
 789
 790#ifdef ENCRYPTION
 791	case TELOPT_ENCRYPT:
 792	    changeok++;
 793	    break;
 794#endif
 795	case TELOPT_LINEMODE:
 796	case TELOPT_TTYPE:
 797	case TELOPT_NAWS:
 798	case TELOPT_TSPEED:
 799	case TELOPT_LFLOW:
 800	case TELOPT_XDISPLOC:
 801#ifdef	TELOPT_ENVIRON
 802	case TELOPT_NEW_ENVIRON:
 803#endif
 804	case TELOPT_OLD_ENVIRON:
 805	default:
 806	    break;
 807	}
 808	if (changeok) {
 809	    set_my_want_state_will(option);
 810	    send_will(option, 0);
 811	} else {
 812	    will_wont_resp[option]++;
 813	    send_wont(option, 0);
 814	}
 815    }
 816    set_my_state_will(option);
 817
 818}  /* end of dooption */
 819
 820void
 821send_wont(int option, int init)
 822{
 823    if (init) {
 824	if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
 825	    my_want_state_is_wont(option))
 826	    return;
 827	set_my_want_state_wont(option);
 828	will_wont_resp[option]++;
 829    }
 830    output_data ((const char *)wont, option);
 831
 832    DIAG(TD_OPTIONS, printoption("td: send wont", option));
 833}
 834
 835void
 836dontoption(int option)
 837{
 838    /*
 839     * Process client input.
 840	 */
 841
 842
 843    DIAG(TD_OPTIONS, printoption("td: recv dont", option));
 844
 845    if (will_wont_resp[option]) {
 846	will_wont_resp[option]--;
 847	if (will_wont_resp[option] && my_state_is_wont(option))
 848	    will_wont_resp[option]--;
 849    }
 850    if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
 851	switch (option) {
 852	case TELOPT_BINARY:
 853	    init_termbuf();
 854	    tty_binaryout(0);
 855	    set_termbuf();
 856	    break;
 857
 858	case TELOPT_ECHO:	/* we should stop echoing */
 859	    {
 860		init_termbuf();
 861		tty_setecho(0);
 862		set_termbuf();
 863	    }
 864	break;
 865
 866	case TELOPT_SGA:
 867	    set_my_want_state_wont(option);
 868	    if (my_state_is_will(option))
 869		send_wont(option, 0);
 870	    set_my_state_wont(option);
 871	    if (turn_on_sga ^= 1)
 872		send_will(option, 1);
 873	    return;
 874
 875	default:
 876	    break;
 877	}
 878
 879	set_my_want_state_wont(option);
 880	if (my_state_is_will(option))
 881	    send_wont(option, 0);
 882    }
 883    set_my_state_wont(option);
 884
 885}  /* end of dontoption */
 886
 887#ifdef	ENV_HACK
 888int env_ovar = -1;
 889int env_ovalue = -1;
 890#else	/* ENV_HACK */
 891# define env_ovar OLD_ENV_VAR
 892# define env_ovalue OLD_ENV_VALUE
 893#endif	/* ENV_HACK */
 894
 895/*
 896 * suboption()
 897 *
 898 *	Look at the sub-option buffer, and try to be helpful to the other
 899 * side.
 900 *
 901 *	Currently we recognize:
 902 *
 903 *	Terminal type is
 904 *	Linemode
 905 *	Window size
 906 *	Terminal speed
 907 */
 908void
 909suboption(void)
 910{
 911    int subchar;
 912
 913    DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
 914
 915    subchar = SB_GET();
 916    switch (subchar) {
 917    case TELOPT_TSPEED: {
 918	int xspeed, rspeed;
 919
 920	if (his_state_is_wont(TELOPT_TSPEED))	/* Ignore if option disabled */
 921	    break;
 922
 923	settimer(tspeedsubopt);
 924
 925	if (SB_EOF() || SB_GET() != TELQUAL_IS)
 926	    return;
 927
 928	xspeed = atoi((char *)subpointer);
 929
 930	while (SB_GET() != ',' && !SB_EOF());
 931	if (SB_EOF())
 932	    return;
 933
 934	rspeed = atoi((char *)subpointer);
 935	clientstat(TELOPT_TSPEED, xspeed, rspeed);
 936
 937	break;
 938
 939    }  /* end of case TELOPT_TSPEED */
 940
 941    case TELOPT_TTYPE: {		/* Yaaaay! */
 942	char *p;
 943
 944	if (his_state_is_wont(TELOPT_TTYPE))	/* Ignore if option disabled */
 945	    break;
 946	settimer(ttypesubopt);
 947
 948	if (SB_EOF() || SB_GET() != TELQUAL_IS) {
 949	    return;		/* ??? XXX but, this is the most robust */
 950	}
 951
 952	p = terminaltype;
 953
 954	while ((p < (terminaltype + sizeof terminaltype-1)) &&
 955	       !SB_EOF()) {
 956	    int c;
 957
 958	    c = SB_GET();
 959	    if (isupper(c)) {
 960		c = tolower(c);
 961	    }
 962	    *p++ = c;    /* accumulate name */
 963	}
 964	*p = 0;
 965	break;
 966    }  /* end of case TELOPT_TTYPE */
 967
 968    case TELOPT_NAWS: {
 969	int xwinsize, ywinsize;
 970
 971	if (his_state_is_wont(TELOPT_NAWS))	/* Ignore if option disabled */
 972	    break;
 973
 974	if (SB_EOF())
 975	    return;
 976	xwinsize = SB_GET() << 8;
 977	if (SB_EOF())
 978	    return;
 979	xwinsize |= SB_GET();
 980	if (SB_EOF())
 981	    return;
 982	ywinsize = SB_GET() << 8;
 983	if (SB_EOF())
 984	    return;
 985	ywinsize |= SB_GET();
 986	clientstat(TELOPT_NAWS, xwinsize, ywinsize);
 987
 988	break;
 989
 990    }  /* end of case TELOPT_NAWS */
 991
 992    case TELOPT_STATUS: {
 993	int mode;
 994
 995	if (SB_EOF())
 996	    break;
 997	mode = SB_GET();
 998	switch (mode) {
 999	case TELQUAL_SEND:
1000	    if (my_state_is_will(TELOPT_STATUS))
1001		send_status();
1002	    break;
1003
1004	case TELQUAL_IS:
1005	    break;
1006
1007	default:
1008	    break;
1009	}
1010	break;
1011    }  /* end of case TELOPT_STATUS */
1012
1013    case TELOPT_XDISPLOC: {
1014	if (SB_EOF() || SB_GET() != TELQUAL_IS)
1015	    return;
1016	settimer(xdisplocsubopt);
1017	subpointer[SB_LEN()] = '\0';
1018	esetenv("DISPLAY", (char *)subpointer, 1);
1019	break;
1020    }  /* end of case TELOPT_XDISPLOC */
1021
1022#ifdef	TELOPT_NEW_ENVIRON
1023    case TELOPT_NEW_ENVIRON:
1024#endif
1025    case TELOPT_OLD_ENVIRON: {
1026	int c;
1027	char *cp, *varp, *valp;
1028
1029	if (SB_EOF())
1030	    return;
1031	c = SB_GET();
1032	if (c == TELQUAL_IS) {
1033	    if (subchar == TELOPT_OLD_ENVIRON)
1034		settimer(oenvironsubopt);
1035	    else
1036		settimer(environsubopt);
1037	} else if (c != TELQUAL_INFO) {
1038	    return;
1039	}
1040
1041#ifdef	TELOPT_NEW_ENVIRON
1042	if (subchar == TELOPT_NEW_ENVIRON) {
1043	    while (!SB_EOF()) {
1044		c = SB_GET();
1045		if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1046		    break;
1047	    }
1048	} else
1049#endif
1050	    {
1051#ifdef	ENV_HACK
1052		/*
1053		 * We only want to do this if we haven't already decided
1054		 * whether or not the other side has its VALUE and VAR
1055		 * reversed.
1056		 */
1057		if (env_ovar < 0) {
1058		    int last = -1;		/* invalid value */
1059		    int empty = 0;
1060		    int got_var = 0, got_value = 0, got_uservar = 0;
1061
1062		    /*
1063		     * The other side might have its VALUE and VAR values
1064		     * reversed.  To be interoperable, we need to determine
1065		     * which way it is.  If the first recognized character
1066		     * is a VAR or VALUE, then that will tell us what
1067		     * type of client it is.  If the fist recognized
1068		     * character is a USERVAR, then we continue scanning
1069		     * the suboption looking for two consecutive
1070		     * VAR or VALUE fields.  We should not get two
1071		     * consecutive VALUE fields, so finding two
1072		     * consecutive VALUE or VAR fields will tell us
1073		     * what the client is.
1074		     */
1075		    SB_SAVE();
1076		    while (!SB_EOF()) {
1077			c = SB_GET();
1078			switch(c) {
1079			case OLD_ENV_VAR:
1080			    if (last < 0 || last == OLD_ENV_VAR
1081				|| (empty && (last == OLD_ENV_VALUE)))
1082				goto env_ovar_ok;
1083			    got_var++;
1084			    last = OLD_ENV_VAR;
1085			    break;
1086			case OLD_ENV_VALUE:
1087			    if (last < 0 || last == OLD_ENV_VALUE
1088				|| (empty && (last == OLD_ENV_VAR)))
1089				goto env_ovar_wrong;
1090			    got_value++;
1091			    last = OLD_ENV_VALUE;
1092			    break;
1093			case ENV_USERVAR:
1094			    /* count strings of USERVAR as one */
1095			    if (last != ENV_USERVAR)
1096				got_uservar++;
1097			    if (empty) {
1098				if (last == OLD_ENV_VALUE)
1099				    goto env_ovar_ok;
1100				if (last == OLD_ENV_VAR)
1101				    goto env_ovar_wrong;
1102			    }
1103			    last = ENV_USERVAR;
1104			    break;
1105			case ENV_ESC:
1106			    if (!SB_EOF())
1107				c = SB_GET();
1108			    /* FALL THROUGH */
1109			default:
1110			    empty = 0;
1111			    continue;
1112			}
1113			empty = 1;
1114		    }
1115		    if (empty) {
1116			if (last == OLD_ENV_VALUE)
1117			    goto env_ovar_ok;
1118			if (last == OLD_ENV_VAR)
1119			    goto env_ovar_wrong;
1120		    }
1121		    /*
1122		     * Ok, the first thing was a USERVAR, and there
1123		     * are not two consecutive VAR or VALUE commands,
1124		     * and none of the VAR or VALUE commands are empty.
1125		     * If the client has sent us a well-formed option,
1126		     * then the number of VALUEs received should always
1127		     * be less than or equal to the number of VARs and
1128		     * USERVARs received.
1129		     *
1130		     * If we got exactly as many VALUEs as VARs and
1131		     * USERVARs, the client has the same definitions.
1132		     *
1133		     * If we got exactly as many VARs as VALUEs and
1134		     * USERVARS, the client has reversed definitions.
1135		     */
1136		    if (got_uservar + got_var == got_value) {
1137		    env_ovar_ok:
1138			env_ovar = OLD_ENV_VAR;
1139			env_ovalue = OLD_ENV_VALUE;
1140		    } else if (got_uservar + got_value == got_var) {
1141		    env_ovar_wrong:
1142			env_ovar = OLD_ENV_VALUE;
1143			env_ovalue = OLD_ENV_VAR;
1144			DIAG(TD_OPTIONS, {
1145			    output_data("ENVIRON VALUE and VAR are reversed!\r\n");
1146			});
1147
1148		    }
1149		}
1150		SB_RESTORE();
1151#endif
1152
1153		while (!SB_EOF()) {
1154		    c = SB_GET();
1155		    if ((c == env_ovar) || (c == ENV_USERVAR))
1156			break;
1157		}
1158	    }
1159
1160	if (SB_EOF())
1161	    return;
1162
1163	cp = varp = (char *)subpointer;
1164	valp = 0;
1165
1166	while (!SB_EOF()) {
1167	    c = SB_GET();
1168	    if (subchar == TELOPT_OLD_ENVIRON) {
1169		if (c == env_ovar)
1170		    c = NEW_ENV_VAR;
1171		else if (c == env_ovalue)
1172		    c = NEW_ENV_VALUE;
1173	    }
1174	    switch (c) {
1175
1176	    case NEW_ENV_VALUE:
1177		*cp = '\0';
1178		cp = valp = (char *)subpointer;
1179		break;
1180
1181	    case NEW_ENV_VAR:
1182	    case ENV_USERVAR:
1183		*cp = '\0';
1184		if (valp)
1185		    esetenv(varp, valp, 1);
1186		else
1187		    unsetenv(varp);
1188		cp = varp = (char *)subpointer;
1189		valp = 0;
1190		break;
1191
1192	    case ENV_ESC:
1193		if (SB_EOF())
1194		    break;
1195		c = SB_GET();
1196		/* FALL THROUGH */
1197	    default:
1198		*cp++ = c;
1199		break;
1200	    }
1201	}
1202	*cp = '\0';
1203	if (valp)
1204	    esetenv(varp, valp, 1);
1205	else
1206	    unsetenv(varp);
1207	break;
1208    }  /* end of case TELOPT_NEW_ENVIRON */
1209#ifdef AUTHENTICATION
1210    case TELOPT_AUTHENTICATION:
1211	if (SB_EOF())
1212	    break;
1213	switch(SB_GET()) {
1214	case TELQUAL_SEND:
1215	case TELQUAL_REPLY:
1216	    /*
1217	     * These are sent by us and cannot be sent by
1218	     * the client.
1219	     */
1220	    break;
1221	case TELQUAL_IS:
1222	    auth_is(subpointer, SB_LEN());
1223	    break;
1224	case TELQUAL_NAME:
1225	    auth_name(subpointer, SB_LEN());
1226	    break;
1227	}
1228	break;
1229#endif
1230#ifdef ENCRYPTION
1231    case TELOPT_ENCRYPT:
1232	if (SB_EOF())
1233	    break;
1234	switch(SB_GET()) {
1235	case ENCRYPT_SUPPORT:
1236	    encrypt_support(subpointer, SB_LEN());
1237	    break;
1238	case ENCRYPT_IS:
1239	    encrypt_is(subpointer, SB_LEN());
1240	    break;
1241	case ENCRYPT_REPLY:
1242	    encrypt_reply(subpointer, SB_LEN());
1243	    break;
1244	case ENCRYPT_START:
1245	    encrypt_start(subpointer, SB_LEN());
1246	    break;
1247	case ENCRYPT_END:
1248	    if (require_encryption)
1249		fatal(net, "Output encryption is not possible to turn off");
1250	    encrypt_end();
1251	    break;
1252	case ENCRYPT_REQSTART:
1253	    encrypt_request_start(subpointer, SB_LEN());
1254	    break;
1255	case ENCRYPT_REQEND:
1256	    /*
1257	     * We can always send an REQEND so that we cannot
1258	     * get stuck encrypting.  We should only get this
1259	     * if we have been able to get in the correct mode
1260	     * anyhow.
1261	     */
1262	    if (require_encryption)
1263		fatal(net, "Input encryption is not possible to turn off");
1264	    encrypt_request_end();
1265	    break;
1266	case ENCRYPT_ENC_KEYID:
1267	    encrypt_enc_keyid(subpointer, SB_LEN());
1268	    break;
1269	case ENCRYPT_DEC_KEYID:
1270	    encrypt_dec_keyid(subpointer, SB_LEN());
1271	    break;
1272	default:
1273	    break;
1274	}
1275	break;
1276#endif
1277
1278    default:
1279	break;
1280    }  /* end of switch */
1281
1282}  /* end of suboption */
1283
1284void
1285doclientstat(void)
1286{
1287    clientstat(TELOPT_LINEMODE, WILL, 0);
1288}
1289
1290#undef ADD
1291#define	ADD(c)	 *ncp++ = c
1292#define	ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1293
1294void
1295send_status(void)
1296{
1297    unsigned char statusbuf[256];
1298    unsigned char *ncp;
1299    unsigned char i;
1300
1301    ncp = statusbuf;
1302
1303    netflush();	/* get rid of anything waiting to go out */
1304
1305    ADD(IAC);
1306    ADD(SB);
1307    ADD(TELOPT_STATUS);
1308    ADD(TELQUAL_IS);
1309
1310    /*
1311     * We check the want_state rather than the current state,
1312     * because if we received a DO/WILL for an option that we
1313     * don't support, and the other side didn't send a DONT/WONT
1314     * in response to our WONT/DONT, then the "state" will be
1315     * WILL/DO, and the "want_state" will be WONT/DONT.  We
1316     * need to go by the latter.
1317     */
1318    for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1319	if (my_want_state_is_will(i)) {
1320	    ADD(WILL);
1321	    ADD_DATA(i);
1322	}
1323	if (his_want_state_is_will(i)) {
1324	    ADD(DO);
1325	    ADD_DATA(i);
1326	}
1327    }
1328
1329    if (his_want_state_is_will(TELOPT_LFLOW)) {
1330	ADD(SB);
1331	ADD(TELOPT_LFLOW);
1332	if (flowmode) {
1333	    ADD(LFLOW_ON);
1334	} else {
1335	    ADD(LFLOW_OFF);
1336	}
1337	ADD(SE);
1338
1339	if (restartany >= 0) {
1340	    ADD(SB);
1341	    ADD(TELOPT_LFLOW);
1342	    if (restartany) {
1343		ADD(LFLOW_RESTART_ANY);
1344	    } else {
1345		ADD(LFLOW_RESTART_XON);
1346	    }
1347	    ADD(SE);
1348	}
1349    }
1350
1351
1352    ADD(IAC);
1353    ADD(SE);
1354
1355    writenet(statusbuf, ncp - statusbuf);
1356    netflush();	/* Send it on its way */
1357
1358    DIAG(TD_OPTIONS,
1359	 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1360}