// state.c

//

// © Portions Copyright (c) Symbian Software Ltd 2007. All rights reserved.

//

/*

 * Copyright (c) 1989, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include "telnetd.h"

#ifdef __SYMBIAN32__

#ifdef __ARMCC__

// Turn off the 'extended constant initialiser used' warning

#pragma diag_suppress 177

#endif//__ARMCC__

#endif//__SYMBIAN32__

#ifndef __SYMBIAN32__

__RCSID("$Heimdal: state.c,v 1.14.12.1 2004/06/21 08:21:58 lha Exp $"

        "$NetBSD: state.c,v 1.3 2004/09/14 08:08:20 lha Exp $");

#endif

unsigned char	doopt[] = { IAC, DO, '%', 'c', 0 };

unsigned char	dont[] = { IAC, DONT, '%', 'c', 0 };

unsigned char	will[] = { IAC, WILL, '%', 'c', 0 };

unsigned char	wont[] = { IAC, WONT, '%', 'c', 0 };

int	not42 = 1;

/*

 * Buffer for sub-options, and macros

 * for suboptions buffer manipulations

 */

unsigned char subbuffer[1024*64], *subpointer= subbuffer, *subend= subbuffer;

#define	SB_CLEAR()	subpointer = subbuffer

#define	SB_TERM()	{ subend = subpointer; SB_CLEAR(); }

#define	SB_ACCUM(c)	if (subpointer < (subbuffer+sizeof subbuffer)) { \

    *subpointer++ = (c); \

			     }

#define	SB_GET()	((*subpointer++)&0xff)

#define	SB_EOF()	(subpointer >= subend)

#define	SB_LEN()	(subend - subpointer)

#ifdef	ENV_HACK

unsigned char *subsave;

#define SB_SAVE()	subsave = subpointer;

#define	SB_RESTORE()	subpointer = subsave;

#endif

/*

 * State for recv fsm

 */

#define	TS_DATA		0	/* base state */

#define	TS_IAC		1	/* look for double IAC's */

#define	TS_CR		2	/* CR-LF ->'s CR */

#define	TS_SB		3	/* throw away begin's... */

#define	TS_SE		4	/* ...end's (suboption negotiation) */

#define	TS_WILL		5	/* will option negotiation */

#define	TS_WONT		6	/* wont -''- */

#define	TS_DO		7	/* do -''- */

#define	TS_DONT		8	/* dont -''- */

void

telrcv(void)

{

    int c;

    static int state = TS_DATA;

    while (ncc > 0) {

	if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)

	    break;

	c = *netip++ & 0377, ncc--;

#ifdef ENCRYPTION

	if (decrypt_input)

	    c = (*decrypt_input)(c);

#endif

	switch (state) {

	case TS_CR:

	    state = TS_DATA;

	    /* Strip off \n or \0 after a \r */

	    if ((c == 0) || (c == '\n')) {

		break;

	    }

	    /* FALL THROUGH */

	case TS_DATA:

	    if (c == IAC) {

		state = TS_IAC;

		break;

	    }

	    /*

	     * We now map \r\n ==> \r for pragmatic reasons.

	     * Many client implementations send \r\n when

	     * the user hits the CarriageReturn key.

	     *

	     * We USED to map \r\n ==> \n, since \r\n says

	     * that we want to be in column 1 of the next

	     * printable line, and \n is the standard

	     * unix way of saying that (\r is only good

	     * if CRMOD is set, which it normally is).

	     */

	    if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {

		int nc = *netip;

#ifdef ENCRYPTION

		if (decrypt_input)

		    nc = (*decrypt_input)(nc & 0xff);

#endif

		{

#ifdef ENCRYPTION

		    if (decrypt_input)

			(void)(*decrypt_input)(-1);

#endif

		    state = TS_CR;

		}

	    }

	    *pfrontp++ = c;

	    break;

	case TS_IAC:

	gotiac:			switch (c) {

	    /*

	     * Send the process on the pty side an

	     * interrupt.  Do this with a NULL or

	     * interrupt char; depending on the tty mode.

	     */

	case IP:

	    DIAG(TD_OPTIONS,

		 printoption("td: recv IAC", c));

	    interrupt();

	    break;

	case BREAK:

	    DIAG(TD_OPTIONS,

		 printoption("td: recv IAC", c));

	    sendbrk();

	    break;

	    /*

	     * Are You There?

	     */

	case AYT:

	    DIAG(TD_OPTIONS,

		 printoption("td: recv IAC", c));

	    recv_ayt();

	    break;

	    /*

	     * Abort Output

	     */

	case AO:

	    {

		DIAG(TD_OPTIONS,

		     printoption("td: recv IAC", c));

		ptyflush();	/* half-hearted */

		init_termbuf();

		if (slctab[SLC_AO].sptr &&

		    *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {

		    *pfrontp++ =

			(unsigned char)*slctab[SLC_AO].sptr;

		}

		netclear();	/* clear buffer back */

		output_data ("%c%c", IAC, DM);

		neturg = nfrontp-1; /* off by one XXX */

		DIAG(TD_OPTIONS,

		     printoption("td: send IAC", DM));

		break;

	    }

	/*

	 * Erase Character and

	 * Erase Line

	 */

	case EC:

	case EL:

	    {

		cc_t ch;

		DIAG(TD_OPTIONS,

		     printoption("td: recv IAC", c));

		ptyflush();	/* half-hearted */

		init_termbuf();

		if (c == EC)

		    ch = *slctab[SLC_EC].sptr;

		else

		    ch = *slctab[SLC_EL].sptr;

		if (ch != (cc_t)(_POSIX_VDISABLE))

		    *pfrontp++ = (unsigned char)ch;

		break;

	    }

	/*

	 * Check for urgent data...

	 */

	case DM:

	    DIAG(TD_OPTIONS,

		 printoption("td: recv IAC", c));

	    SYNCHing = stilloob(net);

	    settimer(gotDM);

	    break;

	    /*

	     * Begin option subnegotiation...

	     */

	case SB:

	    state = TS_SB;

	    SB_CLEAR();

	    continue;

	case WILL:

	    state = TS_WILL;

	    continue;

	case WONT:

	    state = TS_WONT;

	    continue;

	case DO:

	    state = TS_DO;

	    continue;

	case DONT:

	    state = TS_DONT;

	    continue;

	case EOR:

	    if (his_state_is_will(TELOPT_EOR))

		doeof();

	    break;

	    /*

	     * Handle RFC 10xx Telnet linemode option additions

	     * to command stream (EOF, SUSP, ABORT).

	     */

	case xEOF:

	    doeof();

	    break;

	case SUSP:

	    sendsusp();

	    break;

	case ABORT:

	    sendbrk();

	    break;

	case IAC:

	    *pfrontp++ = c;

	    break;

	}

	state = TS_DATA;

	break;

	case TS_SB:

	    if (c == IAC) {

		state = TS_SE;

	    } else {

		SB_ACCUM(c);

	    }

	    break;

	case TS_SE:

	    if (c != SE) {

		if (c != IAC) {

		    /*

		     * bad form of suboption negotiation.

		     * handle it in such a way as to avoid

		     * damage to local state.  Parse

		     * suboption buffer found so far,

		     * then treat remaining stream as

		     * another command sequence.

		     */

		    /* for DIAGNOSTICS */

		    SB_ACCUM(IAC);

		    SB_ACCUM(c);

		    subpointer -= 2;

		    SB_TERM();

		    suboption();

		    state = TS_IAC;

		    goto gotiac;

		}

		SB_ACCUM(c);

		state = TS_SB;

	    } else {

		/* for DIAGNOSTICS */

		SB_ACCUM(IAC);

		SB_ACCUM(SE);

		subpointer -= 2;

		SB_TERM();

		suboption();	/* handle sub-option */

		state = TS_DATA;

	    }

	    break;

	case TS_WILL:

	    willoption(c);

	    state = TS_DATA;

	    continue;

	case TS_WONT:

	    wontoption(c);

	    if (c==TELOPT_ENCRYPT && his_do_dont_is_changing(TELOPT_ENCRYPT) )

                dontoption(c);

	    state = TS_DATA;

	    continue;

	case TS_DO:

	    dooption(c);

	    state = TS_DATA;

	    continue;

	case TS_DONT:

	    dontoption(c);

	    state = TS_DATA;

	    continue;

	default:

#ifndef __SYMBIAN32__	

	    syslog(LOG_ERR, "telnetd: panic state=%d\n", state); 

#endif 	    

	    printf("telnetd: panic state=%d\n", state);

	    exit(1);

	}

    }

}  /* end of telrcv */

/*

 * The will/wont/do/dont state machines are based on Dave Borman's

 * Telnet option processing state machine.

 *

 * These correspond to the following states:

 *	my_state = the last negotiated state

 *	want_state = what I want the state to go to

 *	want_resp = how many requests I have sent

 * All state defaults are negative, and resp defaults to 0.

 *

 * When initiating a request to change state to new_state:

 *

 * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {

 *	do nothing;

 * } else {

 *	want_state = new_state;

 *	send new_state;

 *	want_resp++;

 * }

 *

 * When receiving new_state:

 *

 * if (want_resp) {

 *	want_resp--;

 *	if (want_resp && (new_state == my_state))

 *		want_resp--;

 * }

 * if ((want_resp == 0) && (new_state != want_state)) {

 *	if (ok_to_switch_to new_state)

 *		want_state = new_state;

 *	else

 *		want_resp++;

 *	send want_state;

 * }

 * my_state = new_state;

 *

 * Note that new_state is implied in these functions by the function itself.

 * will and do imply positive new_state, wont and dont imply negative.

 *

 * Finally, there is one catch.  If we send a negative response to a

 * positive request, my_state will be the positive while want_state will

 * remain negative.  my_state will revert to negative when the negative

 * acknowlegment arrives from the peer.  Thus, my_state generally tells

 * us not only the last negotiated state, but also tells us what the peer

 * wants to be doing as well.  It is important to understand this difference

 * as we may wish to be processing data streams based on our desired state

 * (want_state) or based on what the peer thinks the state is (my_state).

 *

 * This all works fine because if the peer sends a positive request, the data

 * that we receive prior to negative acknowlegment will probably be affected

 * by the positive state, and we can process it as such (if we can; if we

 * can't then it really doesn't matter).  If it is that important, then the

 * peer probably should be buffering until this option state negotiation

 * is complete.

 *

 */

void

send_do(int option, int init)

{

    if (init) {

	if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||

	    his_want_state_is_will(option))

	    return;

	/*

	 * Special case for TELOPT_TM:  We send a DO, but pretend

	 * that we sent a DONT, so that we can send more DOs if

	 * we want to.

	 */

	if (option == TELOPT_TM)

	    set_his_want_state_wont(option);

	else

	    set_his_want_state_will(option);

	do_dont_resp[option]++;

    }

    output_data((const char *)doopt, option);

    DIAG(TD_OPTIONS, printoption("td: send do", option));

}

#ifdef	AUTHENTICATION

extern void auth_request(void);

#endif

#ifdef	ENCRYPTION

extern void encrypt_send_support();

#endif

void

willoption(int option)

{

    int changeok = 0;

    void (*func)() = 0;

    /*

     * process input from peer.

     */

    DIAG(TD_OPTIONS, printoption("td: recv will", option));

    if (do_dont_resp[option]) {

	do_dont_resp[option]--;

	if (do_dont_resp[option] && his_state_is_will(option))

	    do_dont_resp[option]--;

    }

    if (do_dont_resp[option] == 0) {

	if (his_want_state_is_wont(option)) {

	    switch (option) {

	    case TELOPT_BINARY:

		init_termbuf();

		tty_binaryin(1);

		set_termbuf();

		changeok++;

		break;

	    case TELOPT_ECHO:

		/*

		 * See comments below for more info.

		 */

		not42 = 0;	/* looks like a 4.2 system */

		break;

	    case TELOPT_TM:

		/*

		 * We never respond to a WILL TM, and

		 * we leave the state WONT.

		 */

		return;

	    case TELOPT_LFLOW:

		/*

		 * If we are going to support flow control

		 * option, then don't worry peer that we can't

		 * change the flow control characters.

		 */

		slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;

		slctab[SLC_XON].defset.flag |= SLC_DEFAULT;

		slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;

		slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;

	    case TELOPT_TTYPE:

	    case TELOPT_SGA:

	    case TELOPT_NAWS:

	    case TELOPT_TSPEED:

	    case TELOPT_XDISPLOC:

	    case TELOPT_NEW_ENVIRON:

	    case TELOPT_OLD_ENVIRON:

		changeok++;

		break;

#ifdef	AUTHENTICATION

	    case TELOPT_AUTHENTICATION:

		func = auth_request;

		changeok++;

		break;

#endif

#ifdef	ENCRYPTION

	    case TELOPT_ENCRYPT:

		func = encrypt_send_support;

		changeok++;

		break;

#endif

	    default:

		break;

	    }

	    if (changeok) {

		set_his_want_state_will(option);

		send_do(option, 0);

	    } else {

		do_dont_resp[option]++;