telnet.c

经典的unix下telnet的c代码

	char *name, **as, **ae;
{
	char **ap;
	int n;

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

int resettermname = 1;

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

	if (resettermname) {
		resettermname = 0;
		if (tnamep && tnamep != unknown)
			free(tnamep);
		if ((tname = (char *)env_getvalue((unsigned char *)"TERM")) &&
				(setupterm(tname, 1, &errret) == OK)) {
			tnamep = mklist(ttytype, tname);
		} else {
			if (tname && ((int)strlen(tname) <= 40)) {
				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;

#if	defined(TN3270)
	    if (tn3270_ttype()) {
		return;
	    }
#endif	/* defined(TN3270) */
	    name = gettermname();
	    len = strlen(name) + 4 + 2;
	    if (len < NETROOM()) {
		snprintf((char *)temp, sizeof(temp), 
			 "%c%c%c%c%s%c%c", IAC, SB, TELOPT_TTYPE,
			 TELQUAL_IS, name, IAC, SE);
		ring_supply_data(&netoring, temp, len);
		printsub('>', &temp[2], len-2);
	    } else {
		ExitString("No room in buffer for terminal type.\n", 1);
		/*NOTREACHED*/
	    }
	}
	break;
    case TELOPT_TSPEED:
	if (my_want_state_is_wont(TELOPT_TSPEED))
	    return;
	if (SB_EOF())
	    return;
	if (SB_GET() == TELQUAL_SEND) {
	    long ospeed, ispeed;
	    unsigned char temp[50];
	    int len;

	    TerminalSpeeds(&ispeed, &ospeed);

	    snprintf((char *)temp, sizeof(temp), 
		     "%c%c%c%c%ld,%ld%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()) {
		ring_supply_data(&netoring, temp, len);
		printsub('>', temp+2, len - 2);
	    }
/*@*/	    else printf("lm_will: not enough room in buffer\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;

	    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;
	    }
	    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()) {
		ring_supply_data(&netoring, temp, len);
		printsub('>', temp+2, len - 2);
	    }
/*@*/	    else printf("lm_will: not enough room in buffer\n");
	}
	break;

#if	defined(AUTHENTICATION)
	case TELOPT_AUTHENTICATION: {
		if (!autologin)
			break;
		if (SB_EOF())
			return;
		switch(SB_GET()) {
		case TELQUAL_IS:
			if (my_want_state_is_dont(TELOPT_AUTHENTICATION))
				return;
			auth_is(subpointer, SB_LEN());
			break;
		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;
		case TELQUAL_NAME:
			if (my_want_state_is_dont(TELOPT_AUTHENTICATION))
				return;
			auth_name(subpointer, SB_LEN());
			break;
		}
	}
	break;
#endif
#if    defined(ENCRYPTION)
	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;
#endif
    default:
	break;
    }
}

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

    void
lm_will(cmd, len)
    unsigned char *cmd;
    int len;
{
    if (len < 1) {
/*@*/	printf("lm_will: no command!!!\n");	/* Should not happen... */
	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 printf("lm_will: not enough room in buffer\n");
	break;
    }
}

    void
lm_wont(cmd, len)
    unsigned char *cmd;
    int len;
{
    if (len < 1) {
/*@*/	printf("lm_wont: no command!!!\n");	/* Should not happen... */
	return;
    }
    switch(cmd[0]) {
    case LM_FORWARDMASK:	/* We shouldn't ever get this... */
    default:
	/* We are always DONT, so don't respond */
	return;
    }
}

    void
lm_do(cmd, len)
    unsigned char *cmd;
    int len;
{
    if (len < 1) {
/*@*/	printf("lm_do: no command!!!\n");	/* Should not happen... */
	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 printf("lm_do: not enough room in buffer\n");
	break;
    }
}

    void
lm_dont(cmd, len)
    unsigned char *cmd;
    int len;
{
    if (len < 1) {
/*@*/	printf("lm_dont: no command!!!\n");	/* Should not happen... */
	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;
	if (*cmd&MODE_ACK)
		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 printf("lm_mode: not enough room in buffer\n");
	setconnmode(0);	/* set changed mode */
}



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

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;

	void
slc_init()
{
	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);
#ifndef	SYSV_TERMIO
	initfunc(SLC_SUSP, SLC_FLUSHIN);
#endif
	initfunc(SLC_EC, 0);
	initfunc(SLC_EL, 0);
#ifndef	SYSV_TERMIO
	initfunc(SLC_EW, 0);
	initfunc(SLC_RP, 0);
	initfunc(SLC_LNEXT, 0);
#endif
	initfunc(SLC_XON, 0);
	initfunc(SLC_XOFF, 0);
#ifdef	SYSV_TERMIO
	spc_data[SLC_XON].mylevel = SLC_CANTCHANGE;
	spc_data[SLC_XOFF].mylevel = SLC_CANTCHANGE;
#endif
	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()
{
    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);
}

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

    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 printf("slc_import: not enough room\n");
}

    void
slc_export()
{
    struct spc *spcp;

    TerminalDefaultChars();

    slc_start_reply();
    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 */
}

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

	slc_start_reply();

	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()
{
    struct spc *spcp;