/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 1988, 1990, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static char sccsid[] = "@(#)telnet.c    8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#include <netdb.h>
#include <sys/types.h>

#include <curses.h>
#include <signal.h>
/*
 * By the way, we need to include curses.h before telnet.h since,
 * among other things, telnet.h #defines 'DO', which is a variable
 * declared in curses.h.
 */

#include <arpa/telnet.h>

#include <ctype.h>

#include "ring.h"

#include "defines.h"
#include "externs.h"
#include "types.h"
#include "general.h"

#include "auth.h"
#include "encrypt.h"

#define strip(x)        ((x)&0x7f)

/* Buffer for sub-options */
static unsigned char    subbuffer[SUBBUFSIZE];
static unsigned char    *subpointer;
static unsigned char    *subend;

#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_PEEK()       ((*subpointer)&0xff)
#define SB_EOF()        (subpointer >= subend)
#define SB_LEN()        (subend - subpointer)

char    options[SUBBUFSIZE];            /* The combined options */
char    do_dont_resp[SUBBUFSIZE];
char    will_wont_resp[SUBBUFSIZE];

int eight = 0;
int autologin = 0;      /* Autologin anyone? */
int skiprc = 0;
int connected;
int showoptions;
static int ISend;       /* trying to send network data in */
int debug = 0;
int crmod;
int netdata;            /* Print out network data flow */
int crlf;               /* Should '\r' be mapped to <CR><LF> (or <CR><NUL>)? */
int telnetport;
int SYNCHing;           /* we are in TELNET SYNCH mode */
int flushout;           /* flush output */
int autoflush = 0;      /* flush output when interrupting? */
int autosynch;          /* send interrupt characters with SYNCH? */
int localflow;          /* we handle flow control locally */
int restartany;         /* if flow control enabled, restart on any character */
int localchars;         /* we recognize interrupt/quit */
int donelclchars;       /* the user has set "localchars" */
int donebinarytoggle;   /* the user has put us in binary */
int dontlecho;          /* do we suppress local echoing right now? */
int eof_pending = 0;    /* we received a genuine EOF on input, send IAC-EOF */
int globalmode;

/* spin while waiting for authentication */
boolean_t scheduler_lockout_tty = B_FALSE;
int encrypt_flag = 0;
int forwardable_flag = 0;
int forward_flag = 0;
boolean_t wantencryption = B_FALSE;

char *prompt = 0;

cc_t escape;
cc_t rlogin;
boolean_t escape_valid = B_TRUE;
#ifdef  KLUDGELINEMODE
cc_t echoc;
#endif

/*
 * Telnet receiver states for fsm
 */
#define TS_DATA         0
#define TS_IAC          1
#define TS_WILL         2
#define TS_WONT         3
#define TS_DO           4
#define TS_DONT         5
#define TS_CR           6
#define TS_SB           7               /* sub-option collection */
#define TS_SE           8               /* looking for sub-option end */

static int      telrcv_state;
#ifdef  OLD_ENVIRON
static  unsigned char telopt_environ = TELOPT_NEW_ENVIRON;
#else
#define telopt_environ  TELOPT_NEW_ENVIRON
#endif

jmp_buf toplevel = { 0 };
jmp_buf peerdied;

static int flushline;
int     linemode;

int     reqd_linemode = 0; /* Set if either new or old line mode in */
                        /* effect since before initial negotiations */

#ifdef  KLUDGELINEMODE
int     kludgelinemode = 1;
#endif

/*
 * The following are some clocks used to decide how to interpret
 * the relationship between various variables.
 */

Clocks clocks;

#ifdef  notdef
Modelist modelist[] = {
        { "telnet command mode", COMMAND_LINE },
        { "character-at-a-time mode", 0 },
        { "character-at-a-time mode (local echo)", LOCAL_ECHO|LOCAL_CHARS },
        { "line-by-line mode (remote echo)", LINE | LOCAL_CHARS },
        { "line-by-line mode", LINE | LOCAL_ECHO | LOCAL_CHARS },
        { "line-by-line mode (local echoing suppressed)", LINE | LOCAL_CHARS },
        { "3270 mode", 0 },
};
#endif

static void willoption(int);
static void wontoption(int);
static void lm_will(unsigned char *, int);
static void lm_wont(unsigned char *, int);
static void lm_do(unsigned char *, int);
static void lm_dont(unsigned char *, int);
static void slc_init(void);
static void slc_import(int);
static void slc_export(void);
static void slc_start_reply(size_t);
static void slc_add_reply(unsigned char, unsigned char, cc_t);
static void slc_end_reply(void);
static void slc(unsigned char *, int);
static int slc_update(void);
static void env_opt(unsigned char *, int);
static void env_opt_start(void);
static void sendeof(void);
static int is_unique(register char *, register char **, register char **);

/*
 * Initialize telnet environment.
 */

int
init_telnet()
{
        if (env_init() == 0)
                return (0);

        SB_CLEAR();
        ClearArray(options);

        connected = ISend = localflow = donebinarytoggle = 0;
        restartany = -1;

        SYNCHing = 0;

        /* Don't change NetTrace */

        escape = CONTROL(']');
        rlogin = _POSIX_VDISABLE;
#ifdef  KLUDGELINEMODE
        echoc = CONTROL('E');
#endif

        flushline = 1;
        telrcv_state = TS_DATA;

        return (1);
}


#ifdef  notdef
#include <varargs.h>

/*VARARGS*/
static void
printring(va_alist)
        va_dcl
{
        va_list ap;
        char buffer[100];               /* where things go */
        char *ptr;
        char *format;
        char *string;
        Ring *ring;
        int i;

        va_start(ap);

        ring = va_arg(ap, Ring *);
        format = va_arg(ap, char *);
        ptr = buffer;

        while ((i = *format++) != 0) {
                if (i == '%') {
                        i = *format++;
                        switch (i) {
                        case 'c':
                                *ptr++ = va_arg(ap, int);
                                break;
                        case 's':
                                string = va_arg(ap, char *);
                                ring_supply_data(ring, buffer, ptr-buffer);
                                ring_supply_data(ring, string, strlen(string));
                                ptr = buffer;
                                break;
                        case 0:
                                ExitString("printring: trailing %%.\n",
                                    EXIT_FAILURE);
                                /*NOTREACHED*/
                        default:
                                ExitString("printring: unknown format "
                                    "character.\n", EXIT_FAILURE);
                                /*NOTREACHED*/
                        }
                } else {
                        *ptr++ = i;
                }
        }
        ring_supply_data(ring, buffer, ptr-buffer);
}
#endif

/*
 * These routines are in charge of sending option negotiations
 * to the other side.
 *
 * The basic idea is that we send the negotiation if either side
 * is in disagreement as to what the current state should be.
 */

void
send_do(c, init)
        register int c, init;
{
        if (init) {
                if (((do_dont_resp[c] == 0) && my_state_is_do(c)) ||
                    my_want_state_is_do(c))
                        return;
                set_my_want_state_do(c);
                do_dont_resp[c]++;
        }
        NET2ADD(IAC, DO);
        NETADD(c);
        printoption("SENT", DO, c);
}

void
send_dont(c, init)
        register int c, init;
{
        if (init) {
                if (((do_dont_resp[c] == 0) && my_state_is_dont(c)) ||
                    my_want_state_is_dont(c))
                        return;
                set_my_want_state_dont(c);
                do_dont_resp[c]++;
        }
        NET2ADD(IAC, DONT);
        NETADD(c);
        printoption("SENT", DONT, c);
}

void
send_will(c, init)
        register int c, init;
{
        if (init) {
                if (((will_wont_resp[c] == 0) && my_state_is_will(c)) ||
                    my_want_state_is_will(c))
                        return;
                set_my_want_state_will(c);
                will_wont_resp[c]++;
        }
        NET2ADD(IAC, WILL);
        NETADD(c);
        printoption("SENT", WILL, c);
}

void
send_wont(c, init)
        register int c, init;
{
        if (init) {
                if (((will_wont_resp[c] == 0) && my_state_is_wont(c)) ||
                    my_want_state_is_wont(c))
                        return;
                set_my_want_state_wont(c);
                will_wont_resp[c]++;
        }
        NET2ADD(IAC, WONT);
        NETADD(c);
        printoption("SENT", WONT, c);
}


static void
willoption(option)
        int option;
{
        int new_state_ok = 0;

        if (do_dont_resp[option]) {
            --do_dont_resp[option];
            if (do_dont_resp[option] && my_state_is_do(option))
                --do_dont_resp[option];
        }

        if ((do_dont_resp[option] == 0) && my_want_state_is_dont(option)) {

            switch (option) {

            case TELOPT_ECHO:
            case TELOPT_SGA:
                if (reqd_linemode && my_state_is_dont(option)) {
                    break;
                }
                /* FALLTHROUGH */
            case TELOPT_BINARY:
                settimer(modenegotiated);
                /* FALLTHROUGH */
            case TELOPT_STATUS:
            case TELOPT_AUTHENTICATION:
                /* FALLTHROUGH */
            case TELOPT_ENCRYPT:
                new_state_ok = 1;
                break;

            case TELOPT_TM:
                if (flushout)
                    flushout = 0;
                /*
                 * Special case for TM.  If we get back a WILL,
                 * pretend we got back a WONT.
                 */
                set_my_want_state_dont(option);
                set_my_state_dont(option);
                return;                 /* Never reply to TM will's/wont's */

            case TELOPT_LINEMODE:
            default:
                break;
            }

            if (new_state_ok) {
                set_my_want_state_do(option);
                send_do(option, 0);
                setconnmode(0);         /* possibly set new tty mode */
            } else {
                do_dont_resp[option]++;
                send_dont(option, 0);
            }
        }
        set_my_state_do(option);
        if (option == TELOPT_ENCRYPT)
                encrypt_send_support();
}

static void
wontoption(option)
        int option;
{
        if (do_dont_resp[option]) {
                --do_dont_resp[option];
                if (do_dont_resp[option] && my_state_is_dont(option))
                        --do_dont_resp[option];
        }

        if ((do_dont_resp[option] == 0) && my_want_state_is_do(option)) {

                switch (option) {

#ifdef  KLUDGELINEMODE
                case TELOPT_SGA:
                        if (!kludgelinemode)
                                break;
                        /* FALLTHROUGH */
#endif
                case TELOPT_ECHO:
                        settimer(modenegotiated);
                        break;

                case TELOPT_TM:
                        if (flushout)
                                flushout = 0;
                        set_my_want_state_dont(option);
                        set_my_state_dont(option);
                        return;         /* Never reply to TM will's/wont's */

                default:
                        break;
                }
                set_my_want_state_dont(option);
                if (my_state_is_do(option))
                        send_dont(option, 0);
                setconnmode(0);                 /* Set new tty mode */
        } else if (option == TELOPT_TM) {
                /*
                 * Special case for TM.
                 */
                if (flushout)
                        flushout = 0;
                set_my_want_state_dont(option);
        }
        set_my_state_dont(option);
}

static void
dooption(option)
        int option;
{
        int new_state_ok = 0;

        if (will_wont_resp[option]) {
                --will_wont_resp[option];
                if (will_wont_resp[option] && my_state_is_will(option))
                        --will_wont_resp[option];
        }

        if (will_wont_resp[option] == 0) {
                if (my_want_state_is_wont(option)) {

                        switch (option) {

                        case TELOPT_TM:
                                /*
                                 * Special case for TM.  We send a WILL,
                                 * but pretend we sent WONT.
                                 */
                                send_will(option, 0);
                                set_my_want_state_wont(TELOPT_TM);
                                set_my_state_wont(TELOPT_TM);
                                return;

                        case TELOPT_BINARY:     /* binary mode */
                        case TELOPT_NAWS:       /* window size */
                        case TELOPT_TSPEED:     /* terminal speed */
                        case TELOPT_LFLOW:      /* local flow control */
                        case TELOPT_TTYPE:      /* terminal type option */
                        case TELOPT_SGA:        /* no big deal */
                        case TELOPT_ENCRYPT:    /* encryption variable option */
                                new_state_ok = 1;
                                break;

                        case TELOPT_NEW_ENVIRON:
                                /* New environment variable option */
#ifdef  OLD_ENVIRON
                                if (my_state_is_will(TELOPT_OLD_ENVIRON))
                                        /* turn off the old */
                                        send_wont(TELOPT_OLD_ENVIRON, 1);
goto env_common;
                        case TELOPT_OLD_ENVIRON:
                                /* Old environment variable option */
                                if (my_state_is_will(TELOPT_NEW_ENVIRON))
                                        /* Don't enable if new one is in use! */
                                        break;
env_common:
                                telopt_environ = option;
#endif
                                new_state_ok = 1;
                                break;

                        case TELOPT_AUTHENTICATION:
                                if (autologin)
                                        new_state_ok = 1;
                                break;

                        case TELOPT_XDISPLOC:   /* X Display location */
                                if (env_getvalue((unsigned char *)"DISPLAY"))
                                        new_state_ok = 1;
                                break;

                        case TELOPT_LINEMODE:
#ifdef  KLUDGELINEMODE
                                kludgelinemode = 0;
                                send_do(TELOPT_SGA, 1);
#endif
                                set_my_want_state_will(TELOPT_LINEMODE);
                                send_will(option, 0);
                                set_my_state_will(TELOPT_LINEMODE);
                                slc_init();
                                return;

                        case TELOPT_ECHO: /* We're never going to echo... */
                        default:
                                break;
                        }

                        if (new_state_ok) {
                                set_my_want_state_will(option);
                                send_will(option, 0);
                                setconnmode(0);         /* Set new tty mode */
                        } else {
                                will_wont_resp[option]++;
                                send_wont(option, 0);
                        }
                } else {
                        /*
                         * Handle options that need more things done after the
                         * other side has acknowledged the option.
                         */
                        switch (option) {
                        case TELOPT_LINEMODE:
#ifdef  KLUDGELINEMODE
                                kludgelinemode = 0;
                                send_do(TELOPT_SGA, 1);
#endif
                                set_my_state_will(option);
                                slc_init();
                                send_do(TELOPT_SGA, 0);
                                return;
                        }
                }
        }
        set_my_state_will(option);
}

        static void
dontoption(option)
        int option;
{

        if (will_wont_resp[option]) {
            --will_wont_resp[option];
            if (will_wont_resp[option] && my_state_is_wont(option))
                --will_wont_resp[option];
        }

        if ((will_wont_resp[option] == 0) && my_want_state_is_will(option)) {
            switch (option) {
            case TELOPT_LINEMODE:
                linemode = 0;   /* put us back to the default state */
                break;
#ifdef  OLD_ENVIRON
            case TELOPT_NEW_ENVIRON:
                /*
                 * The new environ option wasn't recognized, try
                 * the old one.
                 */
                send_will(TELOPT_OLD_ENVIRON, 1);
                telopt_environ = TELOPT_OLD_ENVIRON;
                break;
#endif
            }
            /* we always accept a DONT */
            set_my_want_state_wont(option);
            if (my_state_is_will(option))
                send_wont(option, 0);
            setconnmode(0);                     /* Set new tty mode */
        }
        set_my_state_wont(option);
}

/*
 * Given a buffer returned by tgetent(), this routine will turn
 * the pipe seperated list of names in the buffer into an array
 * of pointers to null terminated names.  We toss out any bad,
 * duplicate, or verbose names (names with spaces).
 */

static char *name_unknown = "UNKNOWN";
static char *unknown[] = { 0, 0 };

static char **
mklist(buf, name)
        char *buf, *name;
{
        register int n;
        register char c, *cp, **argvp, *cp2, **argv, **avt;

        if (name) {
                if (strlen(name) > 40u) {
                        name = 0;
                        unknown[0] = name_unknown;
                } else {
                        unknown[0] = name;
                        upcase(name);
                }
        } else
                unknown[0] = name_unknown;
        /*
         * Count up the number of names.
         */
        for (n = 1, cp = buf; *cp && *cp != ':'; cp++) {
                if (*cp == '|')
                        n++;
        }
        /*
         * Allocate an array to put the name pointers into
         */
        argv = malloc((n+3)*sizeof (char *));
        if (argv == 0)
                return (unknown);

        /*
         * Fill up the array of pointers to names.
         */
        *argv = 0;
        argvp = argv+1;
        n = 0;
        for (cp = cp2 = buf; (c = *cp) != '\0';  cp++) {
                if (c == '|' || c == ':') {
                        *cp++ = '\0';
                        /*
                         * Skip entries that have spaces or are over 40
                         * characters long.  If this is our environment
                         * name, then put it up front.  Otherwise, as
                         * long as this is not a duplicate name (case
                         * insensitive) add it to the list.
                         */
                        if (n || (cp - cp2 > 41))
                                /* EMPTY */;
                        else if (name && (strncasecmp(name, cp2, cp-cp2) == 0))
                                *argv = cp2;
                        else if (is_unique(cp2, argv+1, argvp))
                                *argvp++ = cp2;
                        if (c == ':')
                                break;
                        /*
                         * Skip multiple delimiters. Reset cp2 to
                         * the beginning of the next name. Reset n,
                         * the flag for names with spaces.
                         */
                        while ((c = *cp) == '|')
                                cp++;
                        cp2 = cp;
                        n = 0;
                }
                /*
                 * Skip entries with spaces or non-ascii values.
                 * Convert lower case letters to upper case.
                 */
                if ((c == ' ') || !isascii(c))
                        n = 1;
                else if (islower(c))
                        *cp = toupper(c);
        }

        /*
         * Check for an old V6 2 character name.  If the second
         * name points to the beginning of the buffer, and is
         * only 2 characters long, move it to the end of the array.
         */
        if ((argv[1] == buf) && (strlen(argv[1]) == 2)) {
                --argvp;
                for (avt = &argv[1]; avt < argvp; avt++)
                        *avt = *(avt+1);
                *argvp++ = buf;
        }

        /*
         * Duplicate last name, for TTYPE option, and null
         * terminate the array.  If we didn't find a match on
         * our terminal name, put that name at the beginning.
         */
        cp = *(argvp-1);
        *argvp++ = cp;
        *argvp = 0;

        if (*argv == 0) {
                if (name)
                        *argv = name;
                else {
                        --argvp;
                        for (avt = argv; avt < argvp; avt++)
                                *avt = *(avt+1);
                }
        }
        if (*argv)
                return (argv);
        else
                return (unknown);
}

static int
is_unique(name, as, ae)
        register char *name, **as, **ae;
{
        register char **ap;
        register int n;

        n = strlen(name) + 1;
        for (ap = as; ap < ae; ap++)
                if (strncasecmp(*ap, name, n) == 0)
                        return (0);
        return (1);
}

#define termbuf ttytype
extern char ttytype[];

int resettermname = 1;

static char *
gettermname(void)
{
        char *tname;
        static char **tnamep = 0;
        static char **next;
        int err;

        if (resettermname) {
                resettermname = 0;
                if (tnamep && tnamep != unknown)
                        free(tnamep);
                tname = (char *)env_getvalue((unsigned char *)"TERM");
                if ((tname != NULL) && (setupterm(tname, 1, &err) == 0)) {
                        tnamep = mklist(termbuf, tname);
                } else {
                        if (tname && (strlen(tname) <= 40u)) {
                                unknown[0] = tname;
                                upcase(tname);
                        } else
                                unknown[0] = name_unknown;
                        tnamep = unknown;
                }
                next = tnamep;
        }
        if (*next == 0)
                next = tnamep;
        return (*next++);
}
/*
 * suboption()
 *
 *      Look at the sub-option buffer, and try to be helpful to the other
 * side.
 *
 *      Currently we recognize:
 *
 *              Terminal type, send request.
 *              Terminal speed (send request).
 *              Local flow control (is request).
 *              Linemode
 */

    static void
suboption()
{
        unsigned char subchar;

        printsub('<', subbuffer, SB_LEN()+2);
        switch (subchar = SB_GET()) {
        case TELOPT_TTYPE:
                if (my_want_state_is_wont(TELOPT_TTYPE))
                        return;
                if (SB_EOF() || SB_GET() != TELQUAL_SEND) {
                        return;
                } else {
                        char *name;
                        unsigned char temp[50];
                        int len, bytes;

                        name = gettermname();
                        len = strlen(name) + 4 + 2;
                        bytes = snprintf((char *)temp, sizeof (temp),
                                "%c%c%c%c%s%c%c", IAC, SB,
                                TELOPT_TTYPE, TELQUAL_IS, name, IAC, SE);
                        if ((len < NETROOM()) && (bytes < sizeof (temp))) {
                                        ring_supply_data(&netoring, temp, len);
                                        printsub('>', &temp[2], len-2);
                        } else {
                                ExitString("No room in buffer for "
                                    "terminal type.\n", EXIT_FAILURE);
                                /*NOTREACHED*/
                        }
                }
                break;
        case TELOPT_TSPEED:
                if (my_want_state_is_wont(TELOPT_TSPEED))
                        return;
                if (SB_EOF())
                        return;
                if (SB_GET() == TELQUAL_SEND) {
                        int ospeed, ispeed;
                        unsigned char temp[50];
                        int len, bytes;

                        TerminalSpeeds(&ispeed, &ospeed);

                        bytes = snprintf((char *)temp, sizeof (temp),
                            "%c%c%c%c%d,%d%c%c", IAC, SB,
                            TELOPT_TSPEED, TELQUAL_IS, ospeed, ispeed, IAC, SE);
                        len = strlen((char *)temp+4) + 4; /* temp[3] is 0 ... */

                        if ((len < NETROOM()) && (bytes < sizeof (temp))) {
                                ring_supply_data(&netoring, temp, len);
                                printsub('>', temp+2, len - 2);
                        }
                        else
                                (void) printf(
                                    "telnet: not enough room in buffer "
                                    "for terminal speed option reply\n");
                }
                break;
        case TELOPT_LFLOW:
                if (my_want_state_is_wont(TELOPT_LFLOW))
                        return;
                if (SB_EOF())
                        return;
                switch (SB_GET()) {
                case LFLOW_RESTART_ANY:
                        restartany = 1;
                        break;
                case LFLOW_RESTART_XON:
                        restartany = 0;
                        break;
                case LFLOW_ON:
                        localflow = 1;
                        break;
                case LFLOW_OFF:
                        localflow = 0;
                        break;
                default:
                        return;
                }
                setcommandmode();
                setconnmode(0);
                break;

        case TELOPT_LINEMODE:
                if (my_want_state_is_wont(TELOPT_LINEMODE))
                        return;
                if (SB_EOF())
                        return;
                switch (SB_GET()) {
                case WILL:
                        lm_will(subpointer, SB_LEN());
                        break;
                case WONT:
                        lm_wont(subpointer, SB_LEN());
                        break;
                case DO:
                        lm_do(subpointer, SB_LEN());
                        break;
                case DONT:
                        lm_dont(subpointer, SB_LEN());
                        break;
                case LM_SLC:
                        slc(subpointer, SB_LEN());
                        break;
                case LM_MODE:
                        lm_mode(subpointer, SB_LEN(), 0);
                        break;
                default:
                        break;
                }
                break;

#ifdef  OLD_ENVIRON
        case TELOPT_OLD_ENVIRON:
#endif
        case TELOPT_NEW_ENVIRON:
                if (SB_EOF())
                        return;
                switch (SB_PEEK()) {
                case TELQUAL_IS:
                case TELQUAL_INFO:
                        if (my_want_state_is_dont(subchar))
                                return;
                        break;
                case TELQUAL_SEND:
                        if (my_want_state_is_wont(subchar)) {
                                return;
                        }
                        break;
                default:
                        return;
                }
                env_opt(subpointer, SB_LEN());
                break;

        case TELOPT_XDISPLOC:
                if (my_want_state_is_wont(TELOPT_XDISPLOC))
                        return;
                if (SB_EOF())
                        return;
                if (SB_GET() == TELQUAL_SEND) {
                        unsigned char temp[50], *dp;
                        int len, bytes;

                        if ((dp = env_getvalue((unsigned char *)"DISPLAY")) ==
                            NULL) {
                                /*
                                 * Something happened, we no longer have a
                                 * DISPLAY variable.  So, turn off the option.
                                 */
                                send_wont(TELOPT_XDISPLOC, 1);
                                break;
                        }
                        bytes = snprintf((char *)temp, sizeof (temp),
                            "%c%c%c%c%s%c%c", IAC, SB,
                            TELOPT_XDISPLOC, TELQUAL_IS, dp, IAC, SE);
                        len = strlen((char *)temp+4) + 4; /* temp[3] is 0 ... */

                        if ((len < NETROOM()) && (bytes < sizeof (temp))) {
                                ring_supply_data(&netoring, temp, len);
                                printsub('>', temp+2, len - 2);
                        }
                        else
                                (void) printf(
                                    "telnet: not enough room in buffer"
                                    " for display location option reply\n");
                }
                break;

        case TELOPT_AUTHENTICATION: {
                if (!autologin)
                        break;
                if (SB_EOF())
                        return;
                switch (SB_GET()) {
                case TELQUAL_SEND:
                        if (my_want_state_is_wont(TELOPT_AUTHENTICATION))
                                return;
                        auth_send(subpointer, SB_LEN());
                        break;
                case TELQUAL_REPLY:
                        if (my_want_state_is_wont(TELOPT_AUTHENTICATION))
                                return;
                        auth_reply(subpointer, SB_LEN());
                        break;
                }
        }
        break;

        case TELOPT_ENCRYPT:
                if (SB_EOF())
                        return;
                switch (SB_GET()) {
                case ENCRYPT_START:
                        if (my_want_state_is_dont(TELOPT_ENCRYPT))
                                return;
                        encrypt_start(subpointer, SB_LEN());
                        break;
                case ENCRYPT_END:
                        if (my_want_state_is_dont(TELOPT_ENCRYPT))
                                return;
                        encrypt_end();
                        break;
                case ENCRYPT_SUPPORT:
                        if (my_want_state_is_wont(TELOPT_ENCRYPT))
                                return;
                        encrypt_support(subpointer, SB_LEN());
                        break;
                case ENCRYPT_REQSTART:
                        if (my_want_state_is_wont(TELOPT_ENCRYPT))
                                return;
                        encrypt_request_start(subpointer, SB_LEN());
                        break;
                case ENCRYPT_REQEND:
                        if (my_want_state_is_wont(TELOPT_ENCRYPT))
                                return;
                        /*
                         * We can always send an REQEND so that we cannot
                         * get stuck encrypting.  We should only get this
                         * if we have been able to get in the correct mode
                         * anyhow.
                         */
                        encrypt_request_end();
                        break;
                case ENCRYPT_IS:
                        if (my_want_state_is_dont(TELOPT_ENCRYPT))
                                return;
                        encrypt_is(subpointer, SB_LEN());
                        break;
                case ENCRYPT_REPLY:
                        if (my_want_state_is_wont(TELOPT_ENCRYPT))
                                return;
                        encrypt_reply(subpointer, SB_LEN());
                        break;
                case ENCRYPT_ENC_KEYID:
                        if (my_want_state_is_dont(TELOPT_ENCRYPT))
                                return;
                        encrypt_enc_keyid(subpointer, SB_LEN());
                        break;
                case ENCRYPT_DEC_KEYID:
                        if (my_want_state_is_wont(TELOPT_ENCRYPT))
                                return;
                        encrypt_dec_keyid(subpointer, SB_LEN());
                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }
}

static unsigned char str_lm[] = { IAC, SB, TELOPT_LINEMODE, 0, 0, IAC, SE };

static void
lm_will(cmd, len)
        unsigned char *cmd;
        int len;
{
        if (len < 1) {
                /* Should not happen... */
                (void) printf(
                    "telnet: command missing from linemode WILL request\n");
                return;
        }
        switch (cmd[0]) {
        case LM_FORWARDMASK:    /* We shouldn't ever get this... */
        default:
                str_lm[3] = DONT;
                str_lm[4] = cmd[0];
                if (NETROOM() > sizeof (str_lm)) {
                        ring_supply_data(&netoring, str_lm, sizeof (str_lm));
                        printsub('>', &str_lm[2], sizeof (str_lm)-2);
                }
                else
                        (void) printf("telnet: not enough room in buffer for"
                            "reply to linemode WILL request\n");
                break;
        }
}

static void
lm_wont(cmd, len)
        unsigned char *cmd;
        int len;
{
        if (len < 1) {
                /* Should not happen... */
                (void) printf(
                    "telnet: command missing from linemode WONT request\n");
                return;
        }
        switch (cmd[0]) {
        case LM_FORWARDMASK:    /* We shouldn't ever get this... */
        default:
                /* We are always DONT, so don't respond */
                return;
        }
}

static void
lm_do(cmd, len)
        unsigned char *cmd;
        int len;
{
        if (len < 1) {
                /* Should not happen... */
                (void) printf(
                    "telnet: command missing from linemode DO request\n");
                return;
        }
        switch (cmd[0]) {
        case LM_FORWARDMASK:
        default:
                str_lm[3] = WONT;
                str_lm[4] = cmd[0];
                if (NETROOM() > sizeof (str_lm)) {
                        ring_supply_data(&netoring, str_lm, sizeof (str_lm));
                        printsub('>', &str_lm[2], sizeof (str_lm)-2);
                }
                else
                        (void) printf("telnet: not enough room in buffer for"
                            "reply to linemode DO request\n");
                break;
        }
}

static void
lm_dont(cmd, len)
        unsigned char *cmd;
        int len;
{
        if (len < 1) {
                /* Should not happen... */
                (void) printf(
                    "telnet: command missing from linemode DONT request\n");
                return;
        }
        switch (cmd[0]) {
        case LM_FORWARDMASK:
        default:
                /* we are always WONT, so don't respond */
                break;
        }
}

static unsigned char str_lm_mode[] = {
        IAC, SB, TELOPT_LINEMODE, LM_MODE, 0, IAC, SE
};

        void
lm_mode(cmd, len, init)
        unsigned char *cmd;
        int len, init;
{
        if (len != 1)
                return;
        if ((linemode&MODE_MASK&~MODE_ACK) == *cmd)
                return;
        linemode = *cmd&(MODE_MASK&~MODE_ACK);
        str_lm_mode[4] = linemode;
        if (!init)
                str_lm_mode[4] |= MODE_ACK;
        if (NETROOM() > sizeof (str_lm_mode)) {
                ring_supply_data(&netoring, str_lm_mode, sizeof (str_lm_mode));
                printsub('>', &str_lm_mode[2], sizeof (str_lm_mode)-2);
        }
        else
                (void) printf("telnet: not enough room in buffer for"
                    "reply to linemode request\n");
        setconnmode(0); /* set changed mode */
}



/*
 * slc()
 * Handle special character suboption of LINEMODE.
 */

static struct spc {
        cc_t val;
        cc_t *valp;
        char flags;     /* Current flags & level */
        char mylevel;   /* Maximum level & flags */
} spc_data[NSLC+1];

#define SLC_IMPORT      0
#define SLC_EXPORT      1
#define SLC_RVALUE      2
static int slc_mode = SLC_EXPORT;

static void
slc_init()
{
        register struct spc *spcp;

        localchars = 1;
        for (spcp = spc_data; spcp < &spc_data[NSLC+1]; spcp++) {
                spcp->val = 0;
                spcp->valp = 0;
                spcp->flags = spcp->mylevel = SLC_NOSUPPORT;
        }

#define initfunc(func, flags) { \
                                spcp = &spc_data[func]; \
                                if (spcp->valp = tcval(func)) { \
                                    spcp->val = *spcp->valp; \
                                    spcp->mylevel = SLC_VARIABLE|(flags);\
                                } else { \
                                    spcp->val = 0; \
                                    spcp->mylevel = SLC_DEFAULT; \
                                } \
                            }

        initfunc(SLC_SYNCH, 0);
        /* No BRK */
        initfunc(SLC_AO, 0);
        initfunc(SLC_AYT, 0);
        /* No EOR */
        initfunc(SLC_ABORT, SLC_FLUSHIN|SLC_FLUSHOUT);
        initfunc(SLC_EOF, 0);
        initfunc(SLC_SUSP, SLC_FLUSHIN);
        initfunc(SLC_EC, 0);
        initfunc(SLC_EL, 0);
        initfunc(SLC_EW, 0);
        initfunc(SLC_RP, 0);
        initfunc(SLC_LNEXT, 0);
        initfunc(SLC_XON, 0);
        initfunc(SLC_XOFF, 0);
        initfunc(SLC_FORW1, 0);
#ifdef  USE_TERMIO
        initfunc(SLC_FORW2, 0);
        /* No FORW2 */
#endif

        initfunc(SLC_IP, SLC_FLUSHIN|SLC_FLUSHOUT);
#undef  initfunc

        if (slc_mode == SLC_EXPORT)
                slc_export();
        else
                slc_import(1);

}

void
slcstate()
{
        (void) printf("Special characters are %s values\n",
                slc_mode == SLC_IMPORT ? "remote default" :
                slc_mode == SLC_EXPORT ? "local" :
                                        "remote");
}

void
slc_mode_export()
{
        slc_mode = SLC_EXPORT;
        if (my_state_is_will(TELOPT_LINEMODE))
                slc_export();
}

void
slc_mode_import(def)
    int def;
{
    slc_mode = def ? SLC_IMPORT : SLC_RVALUE;
    if (my_state_is_will(TELOPT_LINEMODE))
        slc_import(def);
}

static unsigned char slc_import_val[] = {
        IAC, SB, TELOPT_LINEMODE, LM_SLC, 0, SLC_VARIABLE, 0, IAC, SE
};
static unsigned char slc_import_def[] = {
        IAC, SB, TELOPT_LINEMODE, LM_SLC, 0, SLC_DEFAULT, 0, IAC, SE
};

static void
slc_import(def)
        int def;
{
        if (NETROOM() > sizeof (slc_import_val)) {
                if (def) {
                        ring_supply_data(&netoring, slc_import_def,
                            sizeof (slc_import_def));
                        printsub('>', &slc_import_def[2],
                            sizeof (slc_import_def)-2);
                } else {
                        ring_supply_data(&netoring, slc_import_val,
                            sizeof (slc_import_val));
                        printsub('>', &slc_import_val[2],
                            sizeof (slc_import_val)-2);
                }
        }
        else
                (void) printf(
                    "telnet: not enough room in buffer for slc import"
                    " request\n");
}

static uchar_t *slc_reply = NULL;
static uchar_t *slc_replyp = NULL;
/*
 * The SLC reply consists of: IAC, SB, TELOPT_LINEMODE, LM_SLC,
 * SLC triplets[], IAC, SE. i.e. it has a 'wrapper' of 6 control characters.
 */
#define SLC_WRAPPER_SIZE 6

static void
slc_export()
{
        register struct spc *spcp;

        TerminalDefaultChars();

        slc_start_reply(NSLC * 3);      /* 3 bytes needed per triplet */
        for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
                if (spcp->mylevel != SLC_NOSUPPORT) {
                        if (spcp->val == (cc_t)(_POSIX_VDISABLE))
                                spcp->flags = SLC_NOSUPPORT;
                        else
                                spcp->flags = spcp->mylevel;
                        if (spcp->valp)
                                spcp->val = *spcp->valp;
                        slc_add_reply(spcp - spc_data, spcp->flags, spcp->val);
                }
        }
        slc_end_reply();
        (void) slc_update();
        setconnmode(1); /* Make sure the character values are set */
}

static void
slc(cp, len)
        register unsigned char *cp;
        int len;
{
        register struct spc *spcp;
        register int func, level;

        slc_start_reply(len);

        for (; len >= 3; len -= 3, cp += 3) {

                func = cp[SLC_FUNC];

                if (func == 0) {
                        /*
                         * Client side: always ignore 0 function.
                         */
                        continue;
                }
                if (func > NSLC) {
                        if ((cp[SLC_FLAGS] & SLC_LEVELBITS) != SLC_NOSUPPORT)
                                slc_add_reply(func, SLC_NOSUPPORT, 0);
                        continue;
                }

                spcp = &spc_data[func];

                level = cp[SLC_FLAGS]&(SLC_LEVELBITS|SLC_ACK);

                if ((cp[SLC_VALUE] == (unsigned char)spcp->val) &&
                    ((level&SLC_LEVELBITS) == (spcp->flags&SLC_LEVELBITS))) {
                        continue;
                }

                if (level == (SLC_DEFAULT|SLC_ACK)) {
                        /*
                         * This is an error condition, the SLC_ACK
                         * bit should never be set for the SLC_DEFAULT
                         * level.  Our best guess to recover is to
                         * ignore the SLC_ACK bit.
                         */
                        cp[SLC_FLAGS] &= ~SLC_ACK;
                }

                if (level == ((spcp->flags&SLC_LEVELBITS)|SLC_ACK)) {
                        spcp->val = (cc_t)cp[SLC_VALUE];
                        spcp->flags = cp[SLC_FLAGS];    /* include SLC_ACK */
                        continue;
                }

                level &= ~SLC_ACK;

                if (level <= (spcp->mylevel&SLC_LEVELBITS)) {
                        spcp->flags = cp[SLC_FLAGS]|SLC_ACK;
                        spcp->val = (cc_t)cp[SLC_VALUE];
                }
                if (level == SLC_DEFAULT) {
                        if ((spcp->mylevel&SLC_LEVELBITS) != SLC_DEFAULT)
                                spcp->flags = spcp->mylevel;
                        else
                                spcp->flags = SLC_NOSUPPORT;
                }
                slc_add_reply(func, spcp->flags, spcp->val);
        }
        slc_end_reply();
        if (slc_update())
                setconnmode(1); /* set the  new character values */
}

void
slc_check()
{
        register struct spc *spcp;

        slc_start_reply(NSLC * 3);      /* 3 bytes needed per triplet */
        for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
                if (spcp->valp && spcp->val != *spcp->valp) {
                        spcp->val = *spcp->valp;
                        if (spcp->val == (cc_t)(_POSIX_VDISABLE))
                                spcp->flags = SLC_NOSUPPORT;
                        else
                                spcp->flags = spcp->mylevel;
                        slc_add_reply(spcp - spc_data, spcp->flags, spcp->val);
                }
        }
        slc_end_reply();
        setconnmode(1);
}

static void
slc_start_reply(size_t len)
{
        /*
         * SLC triplets may contain escaped characters, allow for
         * worst case by allocating 2 bytes for every character.
         */
        slc_reply = realloc(slc_reply, (len * 2) + SLC_WRAPPER_SIZE);
        if (slc_reply == NULL) {
                fprintf(stderr, "telnet: error allocating SLC reply memory\n");
                return;
        }
        slc_replyp = slc_reply;
        *slc_replyp++ = IAC;
        *slc_replyp++ = SB;
        *slc_replyp++ = TELOPT_LINEMODE;
        *slc_replyp++ = LM_SLC;
}

static void
slc_add_reply(unsigned char func, unsigned char flags, cc_t value)
{
        if ((*slc_replyp++ = func) == IAC)
                *slc_replyp++ = IAC;
        if ((*slc_replyp++ = flags) == IAC)
                *slc_replyp++ = IAC;
        if ((*slc_replyp++ = (unsigned char)value) == IAC)
                *slc_replyp++ = IAC;
}

static void
slc_end_reply()
{
        register int len;

        *slc_replyp++ = IAC;
        *slc_replyp++ = SE;
        len = slc_replyp - slc_reply;
        if (len <= SLC_WRAPPER_SIZE)
                return;
        if (NETROOM() > len) {
                ring_supply_data(&netoring, slc_reply, slc_replyp - slc_reply);
                printsub('>', &slc_reply[2], slc_replyp - slc_reply - 2);
        }
        else
                (void) printf("telnet: not enough room in buffer for slc end "
                    "reply\n");
}

static int
slc_update()
{
        register struct spc *spcp;
        int need_update = 0;

        for (spcp = &spc_data[1]; spcp < &spc_data[NSLC+1]; spcp++) {
                if (!(spcp->flags&SLC_ACK))
                        continue;
                spcp->flags &= ~SLC_ACK;
                if (spcp->valp && (*spcp->valp != spcp->val)) {
                        *spcp->valp = spcp->val;
                        need_update = 1;
                }
        }
        return (need_update);
}

#ifdef  OLD_ENVIRON
#ifdef  ENV_HACK
/*
 * Earlier version of telnet/telnetd from the BSD code had
 * the definitions of VALUE and VAR reversed.  To ensure
 * maximum interoperability, we assume that the server is
 * an older BSD server, until proven otherwise.  The newer
 * BSD servers should be able to handle either definition,
 * so it is better to use the wrong values if we don't
 * know what type of server it is.
 */
int env_auto = 1;
int old_env_var = OLD_ENV_VAR;
int old_env_value = OLD_ENV_VALUE;
#else
#define old_env_var     OLD_ENV_VAR
#define old_env_value   OLD_ENV_VALUE
#endif
#endif

static void
env_opt(buf, len)
        register unsigned char *buf;
        register int len;
{
        register unsigned char *ep = 0, *epc = 0;
        register int i;

        switch (buf[0]&0xff) {
        case TELQUAL_SEND:
                env_opt_start();
                if (len == 1) {
                        env_opt_add(NULL);
                } else for (i = 1; i < len; i++) {
                        switch (buf[i]&0xff) {
#ifdef  OLD_ENVIRON
                        case OLD_ENV_VAR:
#ifdef  ENV_HACK
                                if (telopt_environ == TELOPT_OLD_ENVIRON &&
                                    env_auto) {
                                        /* Server has the same definitions */
                                        old_env_var = OLD_ENV_VAR;
                                        old_env_value = OLD_ENV_VALUE;
                                }
                                /* FALLTHROUGH */
#endif
                        case OLD_ENV_VALUE:
                                /*
                                 * Although OLD_ENV_VALUE is not legal, we will
                                 * still recognize it, just in case it is an
                                 * old server that has VAR & VALUE mixed up...
                                 */
                                /* FALLTHROUGH */
#else
                        case NEW_ENV_VAR:
#endif
                        case ENV_USERVAR:
                                if (ep) {
                                        *epc = 0;
                                        env_opt_add(ep);
                                }
                                ep = epc = &buf[i+1];
                                break;
                        case ENV_ESC:
                                i++;
                                /*FALLTHROUGH*/
                        default:
                                if (epc)
                                        *epc++ = buf[i];
                                break;
                        }
                }
                if (ep) {
                        *epc = 0;
                        env_opt_add(ep);
                }
                env_opt_end(1);
                break;

        case TELQUAL_IS:
        case TELQUAL_INFO:
                /* Ignore for now.  We shouldn't get it anyway. */
                break;

        default:
                break;
        }
}

static unsigned char *opt_reply;
static unsigned char *opt_replyp;
static unsigned char *opt_replyend;
#define OPT_REPLY_INITIAL_SIZE  256
/*
 * The opt reply consists of: IAC, SB, telopt_environ, TELQUAL_IS,
 * value, IAC, SE. i.e. it has a 'wrapper' of 6 control characters.
 */
#define OPT_WRAPPER_SIZE 6

static void
env_opt_start()
{
        opt_reply = realloc(opt_reply, OPT_REPLY_INITIAL_SIZE);
        if (opt_reply == NULL) {
                (void) printf(
                    "telnet: error allocating environment option memory\n");
                opt_reply = opt_replyp = opt_replyend = NULL;
                return;
        }
        opt_replyp = opt_reply;
        opt_replyend = opt_reply + OPT_REPLY_INITIAL_SIZE;
        *opt_replyp++ = IAC;
        *opt_replyp++ = SB;
        *opt_replyp++ = telopt_environ;
        *opt_replyp++ = TELQUAL_IS;
}

        void
env_opt_start_info()
{
        env_opt_start();
        if (opt_replyp)
            opt_replyp[-1] = TELQUAL_INFO;
}

        void
env_opt_add(ep)
        register unsigned char *ep;
{
        register unsigned char *vp, c;
        int opt_reply_size;
        int opt_reply_used;

        if (opt_reply == NULL)          /* XXX */
                return;                 /* XXX */

        if (ep == NULL || *ep == '\0') {
                /* Send user defined variables first. */
                (void) env_default(1, 0);
                while (ep = env_default(0, 0))
                        env_opt_add(ep);

                /* Now add the list of well know variables.  */
                (void) env_default(1, 1);
                while (ep = env_default(0, 1))
                        env_opt_add(ep);
                return;
        }
        vp = env_getvalue(ep);

        /*
         * Calculate space required for opt_reply and allocate more if required.
         * Assume worst case that every character is escaped, so needs 2 bytes.
         */
        opt_reply_used = opt_replyp - opt_reply;        /* existing contents */
        opt_reply_size = opt_reply_used + OPT_WRAPPER_SIZE +
            (2 * (strlen((char *)ep))) +
            (vp == NULL ? 0 : (2 * strlen((char *)vp)));

        if (opt_reply_size > (opt_replyend - opt_reply)) {
                opt_reply = realloc(opt_reply, opt_reply_size);
                if (opt_reply == NULL) {
                        (void) printf(
                            "telnet: can't allocate environment option "
                            "reply\n");
                        opt_reply = opt_replyp = opt_replyend = NULL;
                        return;
                }
                opt_replyp = opt_reply + opt_reply_used;
                opt_replyend = opt_reply + opt_reply_size;
        }

        if (opt_welldefined((char *)ep))
#ifdef  OLD_ENVIRON
                if (telopt_environ == TELOPT_OLD_ENVIRON)
                        *opt_replyp++ = old_env_var;
                else
#endif
                        *opt_replyp++ = NEW_ENV_VAR;
        else
                *opt_replyp++ = ENV_USERVAR;
        for (;;) {
                while ((c = *ep++) != '\0') {
                        switch (c&0xff) {
                        case IAC:
                                *opt_replyp++ = IAC;
                                break;
                        case NEW_ENV_VAR:
                        case NEW_ENV_VALUE:
                        case ENV_ESC:
                        case ENV_USERVAR:
                                *opt_replyp++ = ENV_ESC;
                                break;
                        }
                        *opt_replyp++ = c;
                }
                if ((ep = vp) != NULL) {
#ifdef  OLD_ENVIRON
                        if (telopt_environ == TELOPT_OLD_ENVIRON)
                                *opt_replyp++ = old_env_value;
                        else
#endif
                                *opt_replyp++ = NEW_ENV_VALUE;
                        vp = NULL;
                } else
                        break;
        }
}

        int
opt_welldefined(ep)
        char *ep;
{
        if ((strcmp(ep, "USER") == 0) ||
            (strcmp(ep, "DISPLAY") == 0) ||
            (strcmp(ep, "PRINTER") == 0) ||
            (strcmp(ep, "SYSTEMTYPE") == 0) ||
            (strcmp(ep, "JOB") == 0) ||
            (strcmp(ep, "ACCT") == 0))
                return (1);
        return (0);
}
        void
env_opt_end(emptyok)
        register int emptyok;
{
        register int len;

        len = opt_replyp - opt_reply + 2;
        if (emptyok || len > OPT_WRAPPER_SIZE) {
                *opt_replyp++ = IAC;
                *opt_replyp++ = SE;
                if (NETROOM() > len) {
                        ring_supply_data(&netoring, opt_reply, len);
                        printsub('>', &opt_reply[2], len - 2);
                }
                else
                        (void) printf("telnet: not enough room in buffer for "
                            "environment option end reply\n");
        }
        if (opt_reply) {
                free(opt_reply);
                opt_reply = opt_replyp = opt_replyend = NULL;
        }
}



int
telrcv()
{
        register int c;
        register int scc;
        register unsigned char *sbp;
        int count;
        int returnValue = 0;
        int min_room = 0;

        scc = 0;
        count = 0;
        while (--min_room > 2 || (min_room = TTYROOM()) > 2) {
                if (scc == 0) {
                        if (count) {
                                ring_consumed(&netiring, count);
                                returnValue = 1;
                                count = 0;
                        }
                        sbp = netiring.consume;
                        scc = ring_full_consecutive(&netiring);
                        if (scc == 0) {
                                /* No more data coming in */
                                break;
                        }
                }

                c = *sbp++ & 0xff, scc--; count++;

                if (decrypt_input)
                        c = (*decrypt_input)(c);

                switch (telrcv_state) {

                case TS_CR:
                        telrcv_state = TS_DATA;
                        if (c == '\0') {
                                break;  /* Ignore \0 after CR */
                        } else if ((c == '\n') &&
                            my_want_state_is_dont(TELOPT_ECHO) && !crmod) {
                                TTYADD(c);
                                break;
                        }
                        /* FALLTHROUGH */

                case TS_DATA:
                        if (c == IAC) {
                                telrcv_state = TS_IAC;
                                break;
                        }
                        /*
                         * The 'crmod' hack (see following) is needed
                         * since we can't * set CRMOD on output only.
                         * Machines like MULTICS like to send \r without
                         * \n; since we must turn off CRMOD to get proper
                         * input, the mapping is done here (sigh).
                         */
                        if ((c == '\r') &&
                            my_want_state_is_dont(TELOPT_BINARY)) {
                                if (scc > 0) {
                                        c = *sbp&0xff;

                                        if (decrypt_input)
                                                c = (*decrypt_input)(c);

                                        if (c == 0) {
                                                sbp++, scc--; count++;
                                                /* a "true" CR */
                                                TTYADD('\r');
                                        } else if (my_want_state_is_dont(
                                            TELOPT_ECHO) && (c == '\n')) {
                                                sbp++, scc--; count++;
                                                TTYADD('\n');
                                        } else {

                                                if (decrypt_input)
                                                        (*decrypt_input)(-1);

                                                TTYADD('\r');
                                                if (crmod) {
                                                        TTYADD('\n');
                                                }
                                        }
                                } else {
                                        telrcv_state = TS_CR;
                                        TTYADD('\r');
                                        if (crmod) {
                                                TTYADD('\n');
                                        }
                                }
                        } else {
                                TTYADD(c);
                        }
                        continue;

                case TS_IAC:
process_iac:
                        switch (c) {

                        case WILL:
                                telrcv_state = TS_WILL;
                                continue;

                        case WONT:
                                telrcv_state = TS_WONT;
                                continue;

                        case DO:
                                telrcv_state = TS_DO;
                                continue;

                        case DONT:
                                telrcv_state = TS_DONT;
                                continue;

                        case DM:
                                /*
                                 * We may have missed an urgent notification,
                                 * so make sure we flush whatever is in the
                                 * buffer currently.
                                 */
                                printoption("RCVD", IAC, DM);
                                SYNCHing = 1;
                                if (ttyflush(1) == -2) {
                                        /* This will not return. */
                                        fatal_tty_error("write");
                                }
                                SYNCHing = stilloob();
                                settimer(gotDM);
                                break;

                        case SB:
                                SB_CLEAR();
                                telrcv_state = TS_SB;
                                continue;

                        case IAC:
                                TTYADD(IAC);
                                break;

                        case NOP:
                        case GA:
                        default:
                                printoption("RCVD", IAC, c);
                                break;
                        }
                        telrcv_state = TS_DATA;
                        continue;

                case TS_WILL:
                        printoption("RCVD", WILL, c);
                        willoption(c);
                        telrcv_state = TS_DATA;
                        continue;

                case TS_WONT:
                        printoption("RCVD", WONT, c);
                        wontoption(c);
                        telrcv_state = TS_DATA;
                        continue;

                case TS_DO:
                        printoption("RCVD", DO, c);
                        dooption(c);
                        if (c == TELOPT_NAWS) {
                                sendnaws();
                        } else if (c == TELOPT_LFLOW) {
                                localflow = 1;
                                setcommandmode();
                                setconnmode(0);
                        }
                        telrcv_state = TS_DATA;
                        continue;

                case TS_DONT:
                        printoption("RCVD", DONT, c);
                        dontoption(c);
                        flushline = 1;
                        setconnmode(0); /* set new tty mode (maybe) */
                        telrcv_state = TS_DATA;
                        continue;

                case TS_SB:
                        if (c == IAC) {
                                telrcv_state = TS_SE;
                        } else {
                                SB_ACCUM(c);
                        }
                        continue;

                case TS_SE:
                        if (c != SE) {
                                if (c != IAC) {
                        /*
                         * This is an error.  We only expect to get
                         * "IAC IAC" or "IAC SE".  Several things may
                         * have happend.  An IAC was not doubled, the
                         * IAC SE was left off, or another option got
                         * inserted into the suboption are all possibilities.
                         * If we assume that the IAC was not doubled,
                         * and really the IAC SE was left off, we could
                         * get into an infinate loop here.  So, instead,
                         * we terminate the suboption, and process the
                         * partial suboption if we can.
                         */
                                        SB_ACCUM(IAC);
                                        SB_ACCUM(c);
                                        subpointer -= 2;
                                        SB_TERM();

                                        printoption("In SUBOPTION processing, "
                                            "RCVD", IAC, c);
                                        suboption();    /* handle sub-option */
                                        telrcv_state = TS_IAC;
                                        goto process_iac;
                                }
                                SB_ACCUM(c);
                                telrcv_state = TS_SB;
                        } else {
                                SB_ACCUM(IAC);
                                SB_ACCUM(SE);
                                subpointer -= 2;
                                SB_TERM();
                                suboption();    /* handle sub-option */
                                telrcv_state = TS_DATA;
                        }
                }
        }
        if (count)
                ring_consumed(&netiring, count);
        return (returnValue||count);
}

static int bol = 1, local = 0;

int
rlogin_susp()
{
        if (local) {
                local = 0;
                bol = 1;
                command(0, "z\n", 2);
                return (1);
        }
        return (0);
}

static int
telsnd()
{
        int tcc;
        int count;
        int returnValue = 0;
        unsigned char *tbp;

        tcc = 0;
        count = 0;
        while (NETROOM() > 2) {
                register int sc;
                register int c;

                if (tcc == 0) {
                        if (count) {
                                ring_consumed(&ttyiring, count);
                                returnValue = 1;
                                count = 0;
                        }
                        tbp = ttyiring.consume;
                        tcc = ring_full_consecutive(&ttyiring);
                        if (tcc == 0) {
                                break;
                        }
                }
                c = *tbp++ & 0xff, sc = strip(c), tcc--; count++;
                if (rlogin != _POSIX_VDISABLE) {
                        if (bol) {
                                bol = 0;
                                if (sc == rlogin) {
                                        local = 1;
                                        continue;
                                }
                        } else if (local) {
                                local = 0;
                                if (sc == '.' || c == termEofChar) {
                                        bol = 1;
                                        command(0, "close\n", 6);
                                        continue;
                                }
                                if (sc == termSuspChar) {
                                        bol = 1;
                                        command(0, "z\n", 2);
                                        continue;
                                }
                                if (sc == escape) {
                                        command(0, (char *)tbp, tcc);
                                        bol = 1;
                                        count += tcc;
                                        tcc = 0;
                                        flushline = 1;
                                        break;
                                }
                                if (sc != rlogin) {
                                        ++tcc;
                                        --tbp;
                                        --count;
                                        c = sc = rlogin;
                                }
                        }
                        if ((sc == '\n') || (sc == '\r'))
                                bol = 1;
                } else if (sc == escape && escape_valid) {
                        /*
                         * Double escape is a pass through of a single
                         * escape character.
                         */
                        if (tcc && strip(*tbp) == escape) {
                                tbp++;
                                tcc--;
                                count++;
                                bol = 0;
                        } else {
                                command(0, (char *)tbp, tcc);
                                bol = 1;
                                count += tcc;
                                tcc = 0;
                                flushline = 1;
                                break;
                        }
                } else
                        bol = 0;
#ifdef  KLUDGELINEMODE
                if (kludgelinemode && (globalmode&MODE_EDIT) && (sc == echoc)) {
                        if (tcc > 0 && strip(*tbp) == echoc) {
                                tcc--; tbp++; count++;
                        } else {
                                dontlecho = !dontlecho;
                                settimer(echotoggle);
                                setconnmode(0);
                                flushline = 1;
                                break;
                        }
                }
#endif
                if (MODE_LOCAL_CHARS(globalmode)) {
                        if (TerminalSpecialChars(sc) == 0) {
                                bol = 1;
                                break;
                        }
                }
                if (my_want_state_is_wont(TELOPT_BINARY)) {
                        switch (c) {
                        case '\n':
                                /*
                                 * If we are in CRMOD mode (\r ==> \n)
                                 * on our local machine, then probably
                                 * a newline (unix) is CRLF (TELNET).
                                 */
                                if (MODE_LOCAL_CHARS(globalmode)) {
                                        NETADD('\r');
                                }
                                NETADD('\n');
                                bol = flushline = 1;
                                break;
                        case '\r':
                                if (!crlf) {
                                        NET2ADD('\r', '\0');
                                } else {
                                        NET2ADD('\r', '\n');
                                }
                                bol = flushline = 1;
                                break;
                        case IAC:
                                NET2ADD(IAC, IAC);
                                break;
                        default:
                                NETADD(c);
                                break;
                        }
                } else if (c == IAC) {
                        NET2ADD(IAC, IAC);
                } else {
                        NETADD(c);
                }
        }
        if (count)
                ring_consumed(&ttyiring, count);
        return (returnValue||count);    /* Non-zero if we did anything */
}

/*
 * Scheduler()
 *
 * Try to do something.
 *
 * If we do something useful, return 1; else return 0.
 *
 */


int
Scheduler(block)
        int     block;          /* should we block in the select ? */
{
        /*
         * One wants to be a bit careful about setting returnValue
         * to one, since a one implies we did some useful work,
         * and therefore probably won't be called to block next
         * time (TN3270 mode only).
         */
        int returnValue;
        int netin, netout, netex, ttyin, ttyout;

        /* Decide which rings should be processed */

        netout = ring_full_count(&netoring) &&
            (flushline ||
            (my_want_state_is_wont(TELOPT_LINEMODE)
#ifdef  KLUDGELINEMODE
            /* X */ && (!kludgelinemode || my_want_state_is_do(TELOPT_SGA))
#endif
            /* XXX */) ||
            my_want_state_is_will(TELOPT_BINARY));
        ttyout = ring_full_count(&ttyoring);

        ttyin = (ring_empty_count(&ttyiring) && !eof_pending);

        netin = !ISend && ring_empty_count(&netiring);

        netex = !SYNCHing;

        if (scheduler_lockout_tty) {
                ttyin = ttyout = 0;
        }

        /* Call to system code to process rings */

        returnValue = process_rings(netin, netout, netex, ttyin, ttyout,
            !block);

        /* Now, look at the input rings, looking for work to do. */

        if (ring_full_count(&ttyiring)) {
                returnValue |= telsnd();
        } else {
                /*
                 * If ttyiring is empty, check to see if there is a real EOF
                 * pending.  If so, we can maybe do the EOF write now.
                 */
                if (eof_pending) {
                        eof_pending = 0;
                        sendeof();
                }
        }

        if (ring_full_count(&netiring)) {
                returnValue |= telrcv();
        }
        return (returnValue);
}

/*
 * Select from tty and network...
 */
void
telnet(user)
        char *user;
{
        sys_telnet_init();

        {
                static char local_host[MAXHOSTNAMELEN] = { 0 };

                if (!local_host[0]) {
                        (void) gethostname(local_host, sizeof (local_host));
                        local_host[sizeof (local_host)-1] = 0;
                }
                auth_encrypt_init(local_host, hostname, "TELNET");
                auth_encrypt_user(user);
        }

        if (autologin)
                send_will(TELOPT_AUTHENTICATION, 1);

        if (telnetport || wantencryption) {
                send_do(TELOPT_ENCRYPT, 1);
                send_will(TELOPT_ENCRYPT, 1);
        }

        if (telnetport) {
                if (!reqd_linemode)
                    send_do(TELOPT_SGA, 1);
                send_will(TELOPT_TTYPE, 1);
                send_will(TELOPT_NAWS, 1);
                send_will(TELOPT_TSPEED, 1);
                send_will(TELOPT_LFLOW, 1);
                if (!reqd_linemode)
                    send_will(TELOPT_LINEMODE, 1);
                send_will(TELOPT_NEW_ENVIRON, 1);
                send_do(TELOPT_STATUS, 1);
                if (env_getvalue((unsigned char *)"DISPLAY"))
                        send_will(TELOPT_XDISPLOC, 1);
                if (eight)
                        tel_enter_binary(eight);
        }

        /*
         * Note: we assume a tie to the authentication option here.  This
         * is necessary so that authentication fails, we don't spin
         * forever.
         */
        if (wantencryption) {
                boolean_t printed_encrypt = B_FALSE;
                extern boolean_t auth_has_failed;
                time_t timeout = time(0) + 60;

                send_do(TELOPT_ENCRYPT, 1);
                send_will(TELOPT_ENCRYPT, 1);
                for (;;) {
                    if (my_want_state_is_wont(TELOPT_AUTHENTICATION)) {
                        (void) printf(gettext(
                                "\nServer refused to negotiate "
                                "authentication, which is required\n"
                                "for encryption.  Good-bye.\n\r"));
                        Exit(EXIT_FAILURE);
                    }
                    if (auth_has_failed) {
                        (void) printf(gettext(
                            "\nAuthentication negotation has failed, "
                            "which is required for\n"
                            "encryption.  Good-bye.\n\r"));
                        Exit(EXIT_FAILURE);
                    }
                    if (my_want_state_is_dont(TELOPT_ENCRYPT) ||
                        my_want_state_is_wont(TELOPT_ENCRYPT)) {
                            (void) printf(gettext(
                                "\nServer refused to negotiate encryption.  "
                                "Good-bye.\n\r"));
                            Exit(EXIT_FAILURE);
                    }
                    if (encrypt_is_encrypting())
                        break;

                    if (time(0) > timeout) {
                        (void) printf(gettext(
                                "\nEncryption could not be enabled.  "
                                "Good-bye.\n\r"));
                        Exit(EXIT_FAILURE);
                    }
                    if (printed_encrypt == B_FALSE) {
                        printed_encrypt = B_TRUE;
                        (void) printf(gettext(
                            "Waiting for encryption to be negotiated...\n"));
                        /*
                         * Turn on MODE_TRAPSIG and then turn off localchars
                         * so that ^C will cause telnet to exit.
                         */
                        TerminalNewMode(getconnmode()|MODE_TRAPSIG);
                        intr_waiting = 1;
                    }
                    if (intr_happened) {
                        (void) printf(gettext(
                            "\nUser requested an interrupt.  Good-bye.\n\r"));
                        Exit(EXIT_FAILURE);
                    }
                    telnet_spin();
                }
                if (printed_encrypt) {
                        (void) printf(gettext("done.\n"));
                        intr_waiting = 0;
                        setconnmode(0);
                }
        }

        for (;;) {
                int schedValue;

                while ((schedValue = Scheduler(0)) != 0) {
                        if (schedValue == -1) {
                                setcommandmode();
                                return;
                        }
                }

                if (Scheduler(1) == -1) {
                        setcommandmode();
                        return;
                }
        }
}

#if     0       /* XXX - this not being in is a bug */
/*
 * nextitem()
 *
 *      Return the address of the next "item" in the TELNET data
 * stream.  This will be the address of the next character if
 * the current address is a user data character, or it will
 * be the address of the character following the TELNET command
 * if the current address is a TELNET IAC ("I Am a Command")
 * character.
 */

static char *
nextitem(current)
        char *current;
{
        if ((*current&0xff) != IAC) {
                return (current+1);
        }
        switch (*(current+1)&0xff) {
        case DO:
        case DONT:
        case WILL:
        case WONT:
                return (current+3);
        case SB:                /* loop forever looking for the SE */
        {
                register char *look = current+2;

                for (;;) {
                        if ((*look++&0xff) == IAC) {
                                if ((*look++&0xff) == SE) {
                                        return (look);
                                }
                        }
                }
        }
        default:
                return (current+2);
        }
}
#endif  /* 0 */

/*
 * netclear()
 *
 *      We are about to do a TELNET SYNCH operation.  Clear
 * the path to the network.
 *
 *      Things are a bit tricky since we may have sent the first
 * byte or so of a previous TELNET command into the network.
 * So, we have to scan the network buffer from the beginning
 * until we are up to where we want to be.
 *
 *      A side effect of what we do, just to keep things
 * simple, is to clear the urgent data pointer.  The principal
 * caller should be setting the urgent data pointer AFTER calling
 * us in any case.
 */

static void
netclear()
{
#if     0       /* XXX */
        register char *thisitem, *next;
        char *good;
#define wewant(p)       ((nfrontp > p) && ((*p&0xff) == IAC) && \
                                ((*(p+1)&0xff) != EC) && ((*(p+1)&0xff) != EL))

        thisitem = netobuf;

        while ((next = nextitem(thisitem)) <= netobuf.send) {
                thisitem = next;
        }

        /* Now, thisitem is first before/at boundary. */

        good = netobuf; /* where the good bytes go */

        while (netoring.add > thisitem) {
                if (wewant(thisitem)) {
                        int length;

                        next = thisitem;
                        do {
                                next = nextitem(next);
                        } while (wewant(next) && (nfrontp > next));
                        length = next-thisitem;
                        memcpy(good, thisitem, length);
                        good += length;
                        thisitem = next;
                } else {
                        thisitem = nextitem(thisitem);
                }
        }

#endif  /* 0 */
}

/*
 * These routines add various telnet commands to the data stream.
 */

/*
 * doflush -  Send do timing mark (for network connection flush) & then
 * get rid of anything in the output buffer.  Return -1 if there was a
 * non-EWOULDBLOCK error on the tty flush, and otherwise return 0.
 */
static int
doflush()
{
        NET2ADD(IAC, DO);
        NETADD(TELOPT_TM);
        flushline = 1;
        flushout = 1;

        /* Drop pending tty output */
        if (ttyflush(1) == -2)
                return (-1);

        /* do printoption AFTER flush, otherwise the output gets tossed... */
        printoption("SENT", DO, TELOPT_TM);
        return (0);
}

int
xmitAO()
{
        NET2ADD(IAC, AO);
        printoption("SENT", IAC, AO);
        if (autoflush) {
                if (doflush() == -1)
                        return (-1);
        }
        return (0);
}


void
xmitEL()
{
        NET2ADD(IAC, EL);
        printoption("SENT", IAC, EL);
}

void
xmitEC()
{
        NET2ADD(IAC, EC);
        printoption("SENT", IAC, EC);
}


int
dosynch()
{
        netclear();                     /* clear the path to the network */
        NETADD(IAC);
        setneturg();
        NETADD(DM);
        printoption("SENT", IAC, DM);
        return (1);
}

int want_status_response = 0;

int
get_status()
{
        unsigned char tmp[16];
        register unsigned char *cp;

        if (my_want_state_is_dont(TELOPT_STATUS)) {
                (void) printf("Remote side does not support STATUS option\n");
                return (0);
        }
        cp = tmp;

        *cp++ = IAC;
        *cp++ = SB;
        *cp++ = TELOPT_STATUS;
        *cp++ = TELQUAL_SEND;
        *cp++ = IAC;
        *cp++ = SE;
        if (NETROOM() >= cp - tmp) {
                ring_supply_data(&netoring, tmp, cp-tmp);
                printsub('>', tmp+2, cp - tmp - 2);
        }
        ++want_status_response;
        return (1);
}

void
intp()
{
        NET2ADD(IAC, IP);
        printoption("SENT", IAC, IP);
        flushline = 1;
        if (autoflush) {
                /* Ignore return as we're ending off anyway. */
                (void) doflush();
        }
        if (autosynch) {
                (void) dosynch();
        }
}

int
sendbrk()
{
        NET2ADD(IAC, BREAK);
        printoption("SENT", IAC, BREAK);
        flushline = 1;
        if (autoflush) {
                if (doflush() == -1)
                        return (-1);
        }
        if (autosynch) {
                (void) dosynch();
        }
        return (0);
}

void
sendabort()
{
        NET2ADD(IAC, ABORT);
        printoption("SENT", IAC, ABORT);
        flushline = 1;
        if (autoflush) {
                /*
                 * Since sendabort() gets called while aborting,
                 * ignore the doflush() return
                 */
                (void) doflush();
        }
        if (autosynch) {
                (void) dosynch();
        }
}

void
sendsusp()
{
        NET2ADD(IAC, SUSP);
        printoption("SENT", IAC, SUSP);
        flushline = 1;
        if (autoflush) {
                if (doflush() == -1) {
                        /* The following will not return. */
                        fatal_tty_error("write");
                }
        }
        if (autosynch) {
                (void) dosynch();
        }
}

static void
sendeof()
{
        NET2ADD(IAC, xEOF);
        printoption("SENT", IAC, xEOF);
}

/*
 * Send a window size update to the remote system.
 */

void
sendnaws()
{
        unsigned short rows, cols;
        unsigned char tmp[16];
        register unsigned char *cp;

        if (my_state_is_wont(TELOPT_NAWS))
                return;

#define PUTSHORT(cp, x) { if ((*cp++ = ((x)>>8)&0xff) == IAC) *cp++ = IAC; \
                            if ((*cp++ = ((x))&0xff) == IAC) *cp++ = IAC; }

        if (TerminalWindowSize(&rows, &cols) == 0) {    /* Failed */
                return;
        }

        cp = tmp;

        *cp++ = IAC;
        *cp++ = SB;
        *cp++ = TELOPT_NAWS;
        PUTSHORT(cp, cols);
        PUTSHORT(cp, rows);
        *cp++ = IAC;
        *cp++ = SE;
        if (NETROOM() >= cp - tmp) {
                ring_supply_data(&netoring, tmp, cp-tmp);
                printsub('>', tmp+2, cp - tmp - 2);
        }
}

void
tel_enter_binary(rw)
        int rw;
{
        if (rw&1)
                send_do(TELOPT_BINARY, 1);
        if (rw&2)
                send_will(TELOPT_BINARY, 1);
}

void
tel_leave_binary(rw)
        int rw;
{
        if (rw&1)
                send_dont(TELOPT_BINARY, 1);
        if (rw&2)
                send_wont(TELOPT_BINARY, 1);
}