state.c

早期freebsd实现

/*
 * suboption()
 *
 *	Look at the sub-option buffer, and try to be helpful to the other
 * side.
 *
 *	Currently we recognize:
 *
 *	Terminal type is
 *	Linemode
 *	Window size
 *	Terminal speed
 */
	void
suboption()
{
    register int subchar;

    DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});

    subchar = SB_GET();
    switch (subchar) {
    case TELOPT_TSPEED: {
	register int xspeed, rspeed;

	if (his_state_is_wont(TELOPT_TSPEED))	/* Ignore if option disabled */
		break;

	settimer(tspeedsubopt);

	if (SB_EOF() || SB_GET() != TELQUAL_IS)
		return;

	xspeed = atoi((char *)subpointer);

	while (SB_GET() != ',' && !SB_EOF());
	if (SB_EOF())
		return;

	rspeed = atoi((char *)subpointer);
	clientstat(TELOPT_TSPEED, xspeed, rspeed);

	break;

    }  /* end of case TELOPT_TSPEED */

    case TELOPT_TTYPE: {		/* Yaaaay! */
	static char terminalname[41];

	if (his_state_is_wont(TELOPT_TTYPE))	/* Ignore if option disabled */
		break;
	settimer(ttypesubopt);

	if (SB_EOF() || SB_GET() != TELQUAL_IS) {
	    return;		/* ??? XXX but, this is the most robust */
	}

	terminaltype = terminalname;

	while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
								    !SB_EOF()) {
	    register int c;

	    c = SB_GET();
	    if (isupper(c)) {
		c = tolower(c);
	    }
	    *terminaltype++ = c;    /* accumulate name */
	}
	*terminaltype = 0;
	terminaltype = terminalname;
	break;
    }  /* end of case TELOPT_TTYPE */

    case TELOPT_NAWS: {
	register int xwinsize, ywinsize;

	if (his_state_is_wont(TELOPT_NAWS))	/* Ignore if option disabled */
		break;

	if (SB_EOF())
		return;
	xwinsize = SB_GET() << 8;
	if (SB_EOF())
		return;
	xwinsize |= SB_GET();
	if (SB_EOF())
		return;
	ywinsize = SB_GET() << 8;
	if (SB_EOF())
		return;
	ywinsize |= SB_GET();
	clientstat(TELOPT_NAWS, xwinsize, ywinsize);

	break;

    }  /* end of case TELOPT_NAWS */

#ifdef	LINEMODE
    case TELOPT_LINEMODE: {
	register int request;

	if (his_state_is_wont(TELOPT_LINEMODE))	/* Ignore if option disabled */
		break;
	/*
	 * Process linemode suboptions.
	 */
	if (SB_EOF())
	    break;		/* garbage was sent */
	request = SB_GET();	/* get will/wont */

	if (SB_EOF())
	    break;		/* another garbage check */

	if (request == LM_SLC) {  /* SLC is not preceeded by WILL or WONT */
		/*
		 * Process suboption buffer of slc's
		 */
		start_slc(1);
		do_opt_slc(subpointer, subend - subpointer);
		(void) end_slc(0);
		break;
	} else if (request == LM_MODE) {
		if (SB_EOF())
		    return;
		useeditmode = SB_GET();  /* get mode flag */
		clientstat(LM_MODE, 0, 0);
		break;
	}

	if (SB_EOF())
	    break;
	switch (SB_GET()) {  /* what suboption? */
	case LM_FORWARDMASK:
		/*
		 * According to spec, only server can send request for
		 * forwardmask, and client can only return a positive response.
		 * So don't worry about it.
		 */

	default:
		break;
	}
	break;
    }  /* end of case TELOPT_LINEMODE */
#endif
    case TELOPT_STATUS: {
	int mode;

	if (SB_EOF())
	    break;
	mode = SB_GET();
	switch (mode) {
	case TELQUAL_SEND:
	    if (my_state_is_will(TELOPT_STATUS))
		send_status();
	    break;

	case TELQUAL_IS:
	    break;

	default:
	    break;
	}
	break;
    }  /* end of case TELOPT_STATUS */

    case TELOPT_XDISPLOC: {
	if (SB_EOF() || SB_GET() != TELQUAL_IS)
		return;
	settimer(xdisplocsubopt);
	subpointer[SB_LEN()] = '\0';
	(void)setenv("DISPLAY", (char *)subpointer, 1);
	break;
    }  /* end of case TELOPT_XDISPLOC */

#ifdef	TELOPT_NEW_ENVIRON
    case TELOPT_NEW_ENVIRON:
#endif
    case TELOPT_OLD_ENVIRON: {
	register int c;
	register char *cp, *varp, *valp;

	if (SB_EOF())
		return;
	c = SB_GET();
	if (c == TELQUAL_IS) {
		if (subchar == TELOPT_OLD_ENVIRON)
			settimer(oenvironsubopt);
		else
			settimer(environsubopt);
	} else if (c != TELQUAL_INFO) {
		return;
	}

#ifdef	TELOPT_NEW_ENVIRON
	if (subchar == TELOPT_NEW_ENVIRON) {
	    while (!SB_EOF()) {
		c = SB_GET();
		if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
			break;
	    }
	} else
#endif
	{
#ifdef	ENV_HACK
	    /*
	     * We only want to do this if we haven't already decided
	     * whether or not the other side has its VALUE and VAR
	     * reversed.
	     */
	    if (env_ovar < 0) {
		register int last = -1;		/* invalid value */
		int empty = 0;
		int got_var = 0, got_value = 0, got_uservar = 0;

		/*
		 * The other side might have its VALUE and VAR values
		 * reversed.  To be interoperable, we need to determine
		 * which way it is.  If the first recognized character
		 * is a VAR or VALUE, then that will tell us what
		 * type of client it is.  If the fist recognized
		 * character is a USERVAR, then we continue scanning
		 * the suboption looking for two consecutive
		 * VAR or VALUE fields.  We should not get two
		 * consecutive VALUE fields, so finding two
		 * consecutive VALUE or VAR fields will tell us
		 * what the client is.
		 */
		SB_SAVE();
		while (!SB_EOF()) {
			c = SB_GET();
			switch(c) {
			case OLD_ENV_VAR:
				if (last < 0 || last == OLD_ENV_VAR
				    || (empty && (last == OLD_ENV_VALUE)))
					goto env_ovar_ok;
				got_var++;
				last = OLD_ENV_VAR;
				break;
			case OLD_ENV_VALUE:
				if (last < 0 || last == OLD_ENV_VALUE
				    || (empty && (last == OLD_ENV_VAR)))
					goto env_ovar_wrong;
				got_value++;
				last = OLD_ENV_VALUE;
				break;
			case ENV_USERVAR:
				/* count strings of USERVAR as one */
				if (last != ENV_USERVAR)
					got_uservar++;
				if (empty) {
					if (last == OLD_ENV_VALUE)
						goto env_ovar_ok;
					if (last == OLD_ENV_VAR)
						goto env_ovar_wrong;
				}
				last = ENV_USERVAR;
				break;
			case ENV_ESC:
				if (!SB_EOF())
					c = SB_GET();
				/* FALL THROUGH */
			default:
				empty = 0;
				continue;
			}
			empty = 1;
		}
		if (empty) {
			if (last == OLD_ENV_VALUE)
				goto env_ovar_ok;
			if (last == OLD_ENV_VAR)
				goto env_ovar_wrong;
		}
		/*
		 * Ok, the first thing was a USERVAR, and there
		 * are not two consecutive VAR or VALUE commands,
		 * and none of the VAR or VALUE commands are empty.
		 * If the client has sent us a well-formed option,
		 * then the number of VALUEs received should always
		 * be less than or equal to the number of VARs and
		 * USERVARs received.
		 *
		 * If we got exactly as many VALUEs as VARs and
		 * USERVARs, the client has the same definitions.
		 *
		 * If we got exactly as many VARs as VALUEs and
		 * USERVARS, the client has reversed definitions.
		 */
		if (got_uservar + got_var == got_value) {
	    env_ovar_ok:
			env_ovar = OLD_ENV_VAR;
			env_ovalue = OLD_ENV_VALUE;
		} else if (got_uservar + got_value == got_var) {
	    env_ovar_wrong:
			env_ovar = OLD_ENV_VALUE;
			env_ovalue = OLD_ENV_VAR;
			DIAG(TD_OPTIONS, {sprintf(nfrontp,
				"ENVIRON VALUE and VAR are reversed!\r\n");
				nfrontp += strlen(nfrontp);});

		}
	    }
	    SB_RESTORE();
#endif

	    while (!SB_EOF()) {
		c = SB_GET();
		if ((c == env_ovar) || (c == ENV_USERVAR))
			break;
	    }
	}

	if (SB_EOF())
		return;

	cp = varp = (char *)subpointer;
	valp = 0;

	while (!SB_EOF()) {
		c = SB_GET();
		if (subchar == TELOPT_OLD_ENVIRON) {
			if (c == env_ovar)
				c = NEW_ENV_VAR;
			else if (c == env_ovalue)
				c = NEW_ENV_VALUE;
		}
		switch (c) {

		case NEW_ENV_VALUE:
			*cp = '\0';
			cp = valp = (char *)subpointer;
			break;

		case NEW_ENV_VAR:
		case ENV_USERVAR:
			*cp = '\0';
			if (valp)
				(void)setenv(varp, valp, 1);
			else
				unsetenv(varp);
			cp = varp = (char *)subpointer;
			valp = 0;
			break;

		case ENV_ESC:
			if (SB_EOF())
				break;
			c = SB_GET();
			/* FALL THROUGH */
		default:
			*cp++ = c;
			break;
		}
	}
	*cp = '\0';
	if (valp)
		(void)setenv(varp, valp, 1);
	else
		unsetenv(varp);
	break;
    }  /* end of case TELOPT_NEW_ENVIRON */
#if	defined(AUTHENTICATION)
    case TELOPT_AUTHENTICATION:
	if (SB_EOF())
		break;
	switch(SB_GET()) {
	case TELQUAL_SEND:
	case TELQUAL_REPLY:
		/*
		 * These are sent by us and cannot be sent by
		 * the client.
		 */
		break;
	case TELQUAL_IS:
		auth_is(subpointer, SB_LEN());
		break;
	case TELQUAL_NAME:
		auth_name(subpointer, SB_LEN());
		break;
	}
	break;
#endif
#ifdef	ENCRYPTION
    case TELOPT_ENCRYPT:
	if (SB_EOF())
		break;
	switch(SB_GET()) {
	case ENCRYPT_SUPPORT:
		encrypt_support(subpointer, SB_LEN());
		break;
	case ENCRYPT_IS:
		encrypt_is(subpointer, SB_LEN());
		break;
	case ENCRYPT_REPLY:
		encrypt_reply(subpointer, SB_LEN());
		break;
	case ENCRYPT_START:
		encrypt_start(subpointer, SB_LEN());
		break;
	case ENCRYPT_END:
		encrypt_end();
		break;
	case ENCRYPT_REQSTART:
		encrypt_request_start(subpointer, SB_LEN());
		break;
	case ENCRYPT_REQEND:
		/*
		 * 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_ENC_KEYID:
		encrypt_enc_keyid(subpointer, SB_LEN());
		break;
	case ENCRYPT_DEC_KEYID:
		encrypt_dec_keyid(subpointer, SB_LEN());
		break;
	default:
		break;
	}
	break;
#endif	/* ENCRYPTION */

    default:
	break;
    }  /* end of switch */

}  /* end of suboption */

	void
doclientstat()
{
	clientstat(TELOPT_LINEMODE, WILL, 0);
}

#define	ADD(c)	 *ncp++ = c;
#define	ADD_DATA(c) { *ncp++ = c; if (c == SE) *ncp++ = c; }
	void
send_status()
{
	unsigned char statusbuf[256];
	register unsigned char *ncp;
	register unsigned char i;

	ncp = statusbuf;

	netflush();	/* get rid of anything waiting to go out */

	ADD(IAC);
	ADD(SB);
	ADD(TELOPT_STATUS);
	ADD(TELQUAL_IS);

	/*
	 * We check the want_state rather than the current state,
	 * because if we received a DO/WILL for an option that we
	 * don't support, and the other side didn't send a DONT/WONT
	 * in response to our WONT/DONT, then the "state" will be
	 * WILL/DO, and the "want_state" will be WONT/DONT.  We
	 * need to go by the latter.
	 */
	for (i = 0; i < (unsigned char)NTELOPTS; i++) {
		if (my_want_state_is_will(i)) {
			ADD(WILL);
			ADD_DATA(i);
			if (i == IAC)
				ADD(IAC);
		}
		if (his_want_state_is_will(i)) {
			ADD(DO);
			ADD_DATA(i);
			if (i == IAC)
				ADD(IAC);
		}
	}

	if (his_want_state_is_will(TELOPT_LFLOW)) {
		ADD(SB);
		ADD(TELOPT_LFLOW);
		if (flowmode) {
			ADD(LFLOW_ON);
		} else {
			ADD(LFLOW_OFF);
		}
		ADD(SE);

		if (restartany >= 0) {
			ADD(SB)
			ADD(TELOPT_LFLOW);
			if (restartany) {
				ADD(LFLOW_RESTART_ANY);
			} else {
				ADD(LFLOW_RESTART_XON);
			}
			ADD(SE)
			ADD(SB);
		}
	}

#ifdef	LINEMODE
	if (his_want_state_is_will(TELOPT_LINEMODE)) {
		unsigned char *cp, *cpe;
		int len;

		ADD(SB);
		ADD(TELOPT_LINEMODE);
		ADD(LM_MODE);
		ADD_DATA(editmode);
		if (editmode == IAC)
			ADD(IAC);
		ADD(SE);

		ADD(SB);
		ADD(TELOPT_LINEMODE);
		ADD(LM_SLC);
		start_slc(0);
		send_slc();
		len = end_slc(&cp);
		for (cpe = cp + len; cp < cpe; cp++)
			ADD_DATA(*cp);
		ADD(SE);
	}
#endif	/* LINEMODE */

	ADD(IAC);
	ADD(SE);

	writenet(statusbuf, ncp - statusbuf);
	netflush();	/* Send it on its way */

	DIAG(TD_OPTIONS,
		{printsub('>', statusbuf, ncp - statusbuf); netflush();});
}