telnetdaaa.c

经典的unix下telnetd代码

		if (tos
		   && (setsockopt(0, IPPROTO_IP, IP_TOS,
				  (char *)&tos, sizeof(tos)) < 0)
		   && (errno != ENOPROTOOPT) )
			syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
	}
#endif	/* defined(IPPROTO_IP) && defined(IP_TOS) */
	net = 0;
	doit(&from);
	/* NOTREACHED */
	exit(0);
}  /* end of main */

	void
usage()
{
	fprintf(stderr, "Usage: telnetd");
#ifdef	AUTHENTICATION
	fprintf(stderr, " [-a (debug|other|user|valid|off|none)]\n\t");
#endif
#ifdef BFTPDAEMON
	fprintf(stderr, " [-B]");
#endif
	fprintf(stderr, " [-debug]");
#ifdef DIAGNOSTICS
	fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
#endif
#ifdef	AUTHENTICATION
	fprintf(stderr, " [-edebug]");
#endif
	fprintf(stderr, " [-h]");
#if	defined(CRAY) && defined(NEWINIT)
	fprintf(stderr, " [-Iinitid]");
#endif
#if	defined(LINEMODE) && defined(KLUDGELINEMODE)
	fprintf(stderr, " [-k]");
#endif
#ifdef LINEMODE
	fprintf(stderr, " [-l]");
#endif
	fprintf(stderr, " [-n]");
#ifdef	CRAY
	fprintf(stderr, " [-r[lowpty]-[highpty]]");
#endif
	fprintf(stderr, "\n\t");
#ifdef	SecurID
	fprintf(stderr, " [-s]");
#endif
#ifdef	HAS_GETTOS
	fprintf(stderr, " [-S tos]");
#endif
#ifdef	AUTHENTICATION
	fprintf(stderr, " [-X auth-type]");
#endif
	fprintf(stderr, " [-u utmp_hostname_length] [-U]");
	fprintf(stderr, " [port]\n");
	exit(1);
}

/*
 * getterminaltype
 *
 *	Ask the other end to send along its terminal type and speed.
 * Output is the variable terminaltype filled in.
 */
static unsigned char ttytype_sbbuf[] = {
	IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
};

    int
getterminaltype(name)
    char *name;
{
    int retval = -1;
    void _gettermname();

    settimer(baseline);
#if	defined(AUTHENTICATION)
    /*
     * Handle the Authentication option before we do anything else.
     */
    send_do(TELOPT_AUTHENTICATION, 1);
    while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
	ttloop();
    if (his_state_is_will(TELOPT_AUTHENTICATION)) {
	retval = auth_wait(name);
    }
#endif

#ifdef	ENCRYPTION
    send_will(TELOPT_ENCRYPT, 1);
#endif	/* ENCRYPTION */
    send_do(TELOPT_TTYPE, 1);
    send_do(TELOPT_TSPEED, 1);
    send_do(TELOPT_XDISPLOC, 1);
    send_do(TELOPT_NEW_ENVIRON, 1);
    send_do(TELOPT_OLD_ENVIRON, 1);
    while (
#ifdef	ENCRYPTION
	   his_do_dont_is_changing(TELOPT_ENCRYPT) ||
#endif	/* ENCRYPTION */
	   his_will_wont_is_changing(TELOPT_TTYPE) ||
	   his_will_wont_is_changing(TELOPT_TSPEED) ||
	   his_will_wont_is_changing(TELOPT_XDISPLOC) ||
	   his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
	   his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
	ttloop();
    }
#ifdef	ENCRYPTION
    /*
     * Wait for the negotiation of what type of encryption we can
     * send with.  If autoencrypt is not set, this will just return.
     */
    if (his_state_is_will(TELOPT_ENCRYPT)) {
	encrypt_wait();
    }
#endif	/* ENCRYPTION */
    if (his_state_is_will(TELOPT_TSPEED)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };

	memmove(nfrontp, sb, sizeof sb);
	nfrontp += sizeof sb;
	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    if (his_state_is_will(TELOPT_XDISPLOC)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };

	memmove(nfrontp, sb, sizeof sb);
	nfrontp += sizeof sb;
	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };

	memmove(nfrontp, sb, sizeof sb);
	nfrontp += sizeof sb;
	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };

	memmove(nfrontp, sb, sizeof sb);
	nfrontp += sizeof sb;
	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    if (his_state_is_will(TELOPT_TTYPE)) {

	memmove(nfrontp, ttytype_sbbuf, sizeof ttytype_sbbuf);
	nfrontp += sizeof ttytype_sbbuf;
	DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
					sizeof ttytype_sbbuf - 2););
    }
    if (his_state_is_will(TELOPT_TSPEED)) {
	while (sequenceIs(tspeedsubopt, baseline))
	    ttloop();
    }
    if (his_state_is_will(TELOPT_XDISPLOC)) {
	while (sequenceIs(xdisplocsubopt, baseline))
	    ttloop();
    }
    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
	while (sequenceIs(environsubopt, baseline))
	    ttloop();
    }
    if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
	while (sequenceIs(oenvironsubopt, baseline))
	    ttloop();
    }
    if (his_state_is_will(TELOPT_TTYPE)) {
	char first[256], last[256];

	while (sequenceIs(ttypesubopt, baseline))
	    ttloop();

	/*
	 * If the other side has already disabled the option, then
	 * we have to just go with what we (might) have already gotten.
	 */
	if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
	    (void) strncpy(first, terminaltype, sizeof(first));
	    for(;;) {
		/*
		 * Save the unknown name, and request the next name.
		 */
		(void) strncpy(last, terminaltype, sizeof(last));
		_gettermname();
		if (terminaltypeok(terminaltype))
		    break;
		if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
		    his_state_is_wont(TELOPT_TTYPE)) {
		    /*
		     * We've hit the end.  If this is the same as
		     * the first name, just go with it.
		     */
		    if (strncmp(first, terminaltype, sizeof(first)) == 0)
			break;
		    /*
		     * Get the terminal name one more time, so that
		     * RFC1091 compliant telnets will cycle back to
		     * the start of the list.
		     */
		     _gettermname();
		    if (strncmp(first, terminaltype, sizeof(first)) != 0)
			(void) strncpy(terminaltype, first, sizeof(first));
		    break;
		}
	    }
	}
    }
    return(retval);
}  /* end of getterminaltype */

    void
_gettermname()
{
    /*
     * If the client turned off the option,
     * we can't send another request, so we
     * just return.
     */
    if (his_state_is_wont(TELOPT_TTYPE))
	return;
    settimer(baseline);
    memmove(nfrontp, ttytype_sbbuf, sizeof ttytype_sbbuf);
    nfrontp += sizeof ttytype_sbbuf;
    DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
					sizeof ttytype_sbbuf - 2););
    while (sequenceIs(ttypesubopt, baseline))
	ttloop();
}

    int
terminaltypeok(s)
    char *s;
{
    char buf[1024];

    if (terminaltype == NULL)
	return(1);

    /*
     * tgetent() will return 1 if the type is known, and
     * 0 if it is not known.  If it returns -1, it couldn't
     * open the database.  But if we can't open the database,
     * it won't help to say we failed, because we won't be
     * able to verify anything else.  So, we treat -1 like 1.
     */
    if (tgetent(buf, s) == 0)
	return(0);
    return(1);
}

#ifndef	MAXHOSTNAMELEN
#define	MAXHOSTNAMELEN 64
#endif	/* MAXHOSTNAMELEN */

char *hostname;
char host_name[MAXHOSTNAMELEN];
char remote_host_name[MAXHOSTNAMELEN];

#ifndef	convex
extern void telnet P((int, int));
#else
extern void telnet P((int, int, char *));
#endif

/*
 * Get a pty, scan input lines.
 */
void
doit(who)
	struct sockaddr_in *who;
{
	char *host = NULL, *inet_ntoa();
	struct hostent *hp;
	int level;
	int ptynum;
	char user_name[256];

	/*
	 * Find an available pty to use.
	 */
#ifndef	convex
	pty = getpty(&ptynum);
	if (pty < 0)
		fatal(net, "All network ports in use");
#else
	for (;;) {
		char *lp;
		extern char *line, *getpty();

		if ((lp = getpty()) == NULL)
			fatal(net, "Out of ptys");

		if ((pty = open(lp, O_RDWR)) >= 0) {
			strncpy(line,lp, sizeof(line)-1);
			line[sizeof(line)-1] = '\0';
			line[5] = 't';
			break;
		}
	}
#endif

#if	defined(_SC_CRAY_SECURE_SYS)
	/*
	 *	set ttyp line security label
	 */
	if (secflag) {
		char slave_dev[16];

		sprintf(tty_dev, "/dev/pty/%03d", ptynum);
		if (setdevs(tty_dev, &dv) < 0)
		 	fatal(net, "cannot set pty security");
		sprintf(slave_dev, "/dev/ttyp%03d", ptynum);
		if (setdevs(slave_dev, &dv) < 0)
		 	fatal(net, "cannot set tty security");
	}
#endif	/* _SC_CRAY_SECURE_SYS */

	/* get name of connected client */
	hp = gethostbyaddr((char *)&who->sin_addr, sizeof (struct in_addr),
		who->sin_family);

	if (hp == NULL && registerd_host_only) {
		fatal(net, "Couldn't resolve your address into a host name.\r\n\
	 Please contact your net administrator");
	} else if (hp &&
	    (strlen(hp->h_name) <= (unsigned int)((utmp_len < 0) ? -utmp_len
								 : utmp_len))) {
		host = hp->h_name;
	} else {
		host = inet_ntoa(who->sin_addr);
	}
	/*
	 * We must make a copy because Kerberos is probably going
	 * to also do a gethost* and overwrite the static data...
	 */
	strncpy(remote_host_name, host, sizeof(remote_host_name)-1);
	remote_host_name[sizeof(remote_host_name)-1] = 0;
	host = remote_host_name;

	(void) gethostname(host_name, sizeof (host_name));
	hostname = host_name;

#if	defined(AUTHENTICATION) || defined(ENCRYPTION)
	auth_encrypt_init(hostname, host, "TELNETD", 1);
#endif

	init_env();
	/*
	 * get terminal type.
	 */
	*user_name = 0;
	level = getterminaltype(user_name);
	setenv("TERM", terminaltype ? terminaltype : "network", 1);

	/*
	 * Start up the login process on the slave side of the terminal
	 */
#ifndef	convex
	startslave(host, level, user_name);

#if	defined(_SC_CRAY_SECURE_SYS)
	if (secflag) {
		if (setulvl(dv.dv_actlvl) < 0)
			fatal(net,"cannot setulvl()");
		if (setucmp(dv.dv_actcmp) < 0)
			fatal(net, "cannot setucmp()");
	}
#endif	/* _SC_CRAY_SECURE_SYS */

	telnet(net, pty);  /* begin server processing */
#else
	telnet(net, pty, host);
#endif
	/*NOTREACHED*/
}  /* end of doit */

#if	defined(CRAY2) && defined(UNICOS5) && defined(UNICOS50)
	int
Xterm_output(ibufp, obuf, icountp, ocount)
	char **ibufp, *obuf;
	int *icountp, ocount;
{
	int ret;
	ret = term_output(*ibufp, obuf, *icountp, ocount);
	*ibufp += *icountp;
	*icountp = 0;
	return(ret);
}
#define	term_output	Xterm_output
#endif	/* defined(CRAY2) && defined(UNICOS5) && defined(UNICOS50) */

/*
 * Main loop.  Select from pty and network, and
 * hand data to telnet receiver finite state machine.
 */
	void
#ifndef	convex
telnet(f, p)
#else
telnet(f, p, host)
#endif
	int f, p;
#ifdef convex
	char *host;
#endif
{
	int on = 1;
#define	TABBUFSIZ	512
	char	defent[TABBUFSIZ];
	char	defstrs[TABBUFSIZ];
#undef	TABBUFSIZ
	char *HE;
	char *HN;
	char *IM;
	void netflush();
	int nfd;

	/*
	 * Initialize the slc mapping table.
	 */
	get_slc_defaults();

	/*
	 * Do some tests where it is desireable to wait for a response.
	 * Rather than doing them slowly, one at a time, do them all
	 * at once.
	 */
	if (my_state_is_wont(TELOPT_SGA))
		send_will(TELOPT_SGA, 1);
	/*
	 * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
	 * because 4.2 clients are unable to deal with TCP urgent data.
	 *
	 * To find out, we send out a "DO ECHO".  If the remote system
	 * answers "WILL ECHO" it is probably a 4.2 client, and we note
	 * that fact ("WILL ECHO" ==> that the client will echo what
	 * WE, the server, sends it; it does NOT mean that the client will
	 * echo the terminal input).
	 */
	send_do(TELOPT_ECHO, 1);

#ifdef	LINEMODE
	if (his_state_is_wont(TELOPT_LINEMODE)) {
		/* Query the peer for linemode support by trying to negotiate
		 * the linemode option.
		 */
		linemode = 0;
		editmode = 0;
		send_do(TELOPT_LINEMODE, 1);  /* send do linemode */
	}
#endif	/* LINEMODE */

	/*
	 * Send along a couple of other options that we wish to negotiate.
	 */
	send_do(TELOPT_NAWS, 1);
	send_will(TELOPT_STATUS, 1);
	flowmode = 1;		/* default flow control state */
	restartany = -1;	/* uninitialized... */
	send_do(TELOPT_LFLOW, 1);

	/*
	 * Spin, waiting for a response from the DO ECHO.  However,
	 * some REALLY DUMB telnets out there might not respond
	 * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
	 * telnets so far seem to respond with WONT for a DO that
	 * they don't understand...) because by the time we get the
	 * response, it will already have processed the DO ECHO.
	 * Kludge upon kludge.
	 */
	while (his_will_wont_is_changing(TELOPT_NAWS))
		ttloop();

	/*
	 * But...
	 * The client might have sent a WILL NAWS as part of its
	 * startup code; if so, we'll be here before we get the
	 * response to the DO ECHO.  We'll make the assumption
	 * that any implementation that understands about NAWS
	 * is a modern enough implementation that it will respond
	 * to our DO ECHO request; hence we'll do another spin
	 * waiting for the ECHO option to settle down, which is
	 * what we wanted to do in the first place...
	 */
	if (his_want_state_is_will(TELOPT_ECHO) &&
	    his_state_is_will(TELOPT_NAWS)) {
		while (his_will_wont_is_changing(TELOPT_ECHO))
			ttloop();
	}
	/*
	 * On the off chance that the telnet client is broken and does not
	 * respond to the DO ECHO we sent, (after all, we did send the
	 * DO NAWS negotiation after the DO ECHO, and we won't get here
	 * until a response to the DO NAWS comes back) simulate the
	 * receipt of a will echo.  This will also send a WONT ECHO
	 * to the client, since we assume that the client failed to
	 * respond because it believes that it is already in DO ECHO
	 * mode, which we do not want.
	 */
	if (his_want_state_is_will(TELOPT_ECHO)) {
		DIAG(TD_OPTIONS,
			{sprintf(nfrontp, "td: simulating recv\r\n");
			 nfrontp += strlen(nfrontp);});
		willoption(TELOPT_ECHO);
	}

	/*
	 * Finally, to clean things up, we turn on our echo.  This
	 * will break stupid 4.2 telnets out of local terminal echo.
	 */

	if (my_state_is_wont(TELOPT_ECHO))
		send_will(TELOPT_ECHO, 1);

#ifndef	STREAMSPTY
	/*
	 * Turn on packet mode
	 */
	(void) ioctl(p, TIOCPKT, (char *)&on);
#endif

#if	defined(LINEMODE) && defined(KLUDGELINEMODE)
	/*
	 * Continuing line mode support.  If client does not support
	 * real linemode, attempt to negotiate kludge linemode by sending
	 * the do timing mark sequence.
	 */
	if (lmodetype < REAL_LINEMODE)
		send_do(TELOPT_TM, 1);
#endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */

	/*
	 * Call telrcv() once to pick up anything received during
	 * terminal type negotiation, 4.2/4.3 determination, and
	 * linemode negotiation.
	 */
	telrcv();

	(void) ioctl(f, FIONBIO, (char *)&on);
	(void) ioctl(p, FIONBIO, (char *)&on);
#if	defined(CRAY2) && defined(UNICOS5)