telnet.c

经典的unix下telnet的c代码

/*	$OpenBSD: telnet.c,v 1.18 2003/11/08 19:17:29 jmc Exp $	*/
/*	$NetBSD: telnet.c,v 1.7 1996/02/28 21:04:15 thorpej Exp $	*/

/*
 * 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. 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 "telnet_locl.h"
#include <curses.h>
#include <term.h>

#define        strip(x) (eight ? (x) : ((x) & 0x7f))

static unsigned char	subbuffer[SUBBUFSIZE],
			*subpointer, *subend;	 /* buffer for sub-options */
#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[256];		/* The combined options */
char	do_dont_resp[256];
char	will_wont_resp[256];

int
	eight = 3,
	binary = 0,
	autologin = 0,	/* Autologin anyone? */
	skiprc = 0,
	connected,
	showoptions,
	In3270,		/* Are we in 3270 mode? */
	ISend,		/* trying to send network data in */
	debug = 0,
	crmod,
	netdata,	/* Print out network data flow */
	crlf,		/* Should '\r' be mapped to <CR><LF> (or <CR><NUL>)? */
#if	defined(TN3270)
	noasynchtty = 0,/* User specified "-noasynch" on command line */
	noasynchnet = 0,/* User specified "-noasynch" on command line */
	askedSGA = 0,	/* We have talked about suppress go ahead */
#endif	/* defined(TN3270) */
	telnetport,
	wantencryption = 0,
	SYNCHing,	/* we are in TELNET SYNCH mode */
	flushout,	/* flush output */
	autoflush = 0,	/* flush output when interrupting? */
	autosynch,	/* send interrupt characters with SYNCH? */
	localflow,	/* we handle flow control locally */
	restartany,	/* if flow control enabled, restart on any character */
	localchars,	/* we recognize interrupt/quit */
	donelclchars,	/* the user has set "localchars" */
	donebinarytoggle,	/* the user has put us in binary */
	dontlecho,	/* do we suppress local echoing right now? */
	globalmode,
	clienteof = 0;

char *prompt = 0;

int scheduler_lockout_tty = 0;

cc_t escape;
cc_t rlogin;
#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
unsigned char telopt_environ = TELOPT_NEW_ENVIRON;
#else
# define telopt_environ TELOPT_NEW_ENVIRON
#endif

jmp_buf	toplevel = { 0 };
jmp_buf	peerdied;

int	flushline;
int	linemode;

#ifdef	KLUDGELINEMODE
int	kludgelinemode = 1;
#endif

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

Clocks clocks;


/*
 * Initialize telnet environment.
 */

    void
init_telnet()
{
    env_init();

    SB_CLEAR();
    memset((char *)options, 0, sizeof options);

    connected = In3270 = ISend = localflow = donebinarytoggle = 0;
#if	defined(AUTHENTICATION) || defined(ENCRYPTION)
    auth_encrypt_connect(connected);
#endif	/* defined(AUTHENTICATION) || defined(ENCRYPTION) */
    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;
}


/*
 * 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)
    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)
    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)
    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)
    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);
}


	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:
#	    if defined(TN3270)
		/*
		 * The following is a pain in the rear-end.
		 * Various IBM servers (some versions of Wiscnet,
		 * possibly Fibronics/Spartacus, and who knows who
		 * else) will NOT allow us to send "DO SGA" too early
		 * in the setup proceedings.  On the other hand,
		 * 4.2 servers (telnetd) won't set SGA correctly.
		 * So, we are stuck.  Empirically (but, based on
		 * a VERY small sample), the IBM servers don't send
		 * out anything about ECHO, so we postpone our sending
		 * "DO SGA" until we see "WILL ECHO" (which 4.2 servers
		 * DO send).
		  */
		{
		    if (askedSGA == 0) {
			askedSGA = 1;
			if (my_want_state_is_dont(TELOPT_SGA))
			    send_do(TELOPT_SGA, 1);
		    }
		}
		    /* Fall through */
	    case TELOPT_EOR:
#endif	    /* defined(TN3270) */
	    case TELOPT_BINARY:
	    case TELOPT_SGA:
		settimer(modenegotiated);
		/* FALL THROUGH */
	    case TELOPT_STATUS:
#if	defined(AUTHENTICATION)
	    case TELOPT_AUTHENTICATION:
#endif
#if    defined(ENCRYPTION)
	    case TELOPT_ENCRYPT:
#endif
		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    defined(ENCRYPTION)
	if (option == TELOPT_ENCRYPT)
		encrypt_send_support();
#endif

}

	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;
		/* FALL THROUGH */
#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 */

#ifdef ENCRYPTION
	    case TELOPT_ENCRYPT:
		encrypt_not();
		break;
#endif
	    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;

#	if defined(TN3270)
	    case TELOPT_EOR:		/* end of record */
#	endif	/* defined(TN3270) */
	    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 */
#if    defined(ENCRYPTION)
	    case TELOPT_ENCRYPT:        /* encryption variable option */
#endif
		new_state_ok = 1;
		break;

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

#if	defined(AUTHENTICATION)
	    case TELOPT_AUTHENTICATION:
		if (autologin)
			new_state_ok = 1;
		break;
#endif

	    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);
}

/*
 * This routine will turn a pipe separated list of names in the buffer
 * into an array of pointers to NUL terminated names.  We toss out any
 * bad, duplicate, or verbose names (names with spaces).
 */

int is_unique(char *, char **, char **);

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

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

	if (name) {
		if ((int)strlen(name) > 40) {
			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++) {
		if (*cp == '|')
			n++;
	}
	/*
	 * Allocate an array to put the name pointers into
	 */
	argv = (char **)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);  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))
				;
			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.
		 */
#define ISASCII(c) (!((c)&0x80))
		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);
}

	int
is_unique(name, as, ae)