telnetd.c   [plain text]

/*
 * Copyright (c) 1989, 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 copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

/* based on @(#)telnetd.c	8.1 (Berkeley) 6/4/93 */

#include "telnetd.h"
#include "pathnames.h"

extern int getent(char *, char *);
extern int tgetent(char *, char *);

#if	defined(_SC_CRAY_SECURE_SYS) && !defined(SCM_SECURITY)
/*
 * UNICOS 6.0/6.1 do not have SCM_SECURITY defined, so we can
 * use it to tell us to turn off all the socket security code,
 * since that is only used in UNICOS 7.0 and later.
 */
# undef _SC_CRAY_SECURE_SYS
#endif

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <libpty.h>
#include <com_err.h>
#if	defined(_SC_CRAY_SECURE_SYS)
#include <sys/sysv.h>
#include <sys/secdev.h>
# ifdef SO_SEC_MULTI		/* 8.0 code */
#include <sys/secparm.h>
#include <sys/usrv.h>
# endif /* SO_SEC_MULTI */
int	secflag;
char	tty_dev[16];
struct	secdev dv;
struct	sysv sysv;
# ifdef SO_SEC_MULTI		/* 8.0 code */
struct	socksec ss;
# else /* SO_SEC_MULTI */	/* 7.0 code */
struct	socket_security ss;
# endif /* SO_SEC_MULTI */
#endif	/* _SC_CRAY_SECURE_SYS */

#include "fake-addrinfo.h"

#ifdef KRB5
#include "krb5.h"
#endif

#if	defined(AUTHENTICATION)
#include <libtelnet/auth.h>
#include <libtelnet/auth-proto.h>
#endif
#ifdef ENCRYPTION
#include <libtelnet/encrypt.h>
#include <libtelnet/enc-proto.h>
#endif
#if	defined(AUTHENTICATION) || defined(ENCRYPTION)
#include <libtelnet/misc-proto.h>
#endif

int	registerd_host_only = 0;

#ifdef	STREAMSPTY
#include <sys/stream.h>
# include <stropts.h>
# include <termio.h>
/* make sure we don't get the bsd version */
#ifdef HAVE_SYS_TTY_H
# include "/usr/include/sys/tty.h"
#endif
#ifdef  HAVE_SYS_PTYVAR_H
# include <sys/ptyvar.h>
#endif

/*
 * Because of the way ptyibuf is used with streams messages, we need
 * ptyibuf+1 to be on a full-word boundary.  The following wierdness
 * is simply to make that happen.
 */
long	ptyibufbuf[BUFSIZ/sizeof(long)+1];
char	*ptyibuf = ((char *)&ptyibufbuf[1])-1;
char	*ptyip = ((char *)&ptyibufbuf[1])-1;
char	ptyibuf2[BUFSIZ];
unsigned char ctlbuf[BUFSIZ];
struct	strbuf strbufc, strbufd;

int readstream();

#else	/* ! STREAMPTY */

/*
 * I/O data buffers,
 * pointers, and counters.
 */
char	ptyibuf[BUFSIZ], *ptyip = ptyibuf;
char	ptyibuf2[BUFSIZ];

#endif /* ! STREAMPTY */

static void doit (struct sockaddr *);
int terminaltypeok (char *);
static void _gettermname(void);

int	hostinfo = 1;			/* do we print login banner? */

#ifdef	CRAY
extern int      newmap; /* nonzero if \n maps to ^M^J */
int	lowpty = 0, highpty;	/* low, high pty numbers */
#endif /* CRAY */

int debug = 0;
int keepalive = 1;
char *progname;

int maxhostlen = 0;
int always_ip = 0;
int stripdomain = 1;

extern void usage (void);

/*
 * The string to pass to getopt().  We do it this way so
 * that only the actual options that we support will be
 * passed off to getopt().
 */
char valid_opts[] = {
	'd', ':', 'h', 'k', 'L', ':', 'n', 'S', ':', 'U',
	'w', ':',
#ifdef	AUTHENTICATION
	'a', ':', 'X', ':',
#endif
#ifdef BFTPDAEMON
	'B',
#endif
#ifdef DIAGNOSTICS
	'D', ':',
#endif
#ifdef	ENCRYPTION
	'e',
#endif
#if	defined(CRAY) && defined(NEWINIT)
	'I', ':',
#endif
#ifdef	LINEMODE
	'l',
#endif
#ifdef CRAY
	'r', ':',
#endif
#ifdef	SecurID
	's',
#endif
#ifdef KRB5
	'R', ':', 't', ':',
#endif
	'\0'
};

#include <sys/utsname.h>
static char *
get_default_IM()
{
	struct utsname name;
	static char banner[1024];
	
	if (uname(&name) < 0)
		sprintf(banner, "\r\nError getting hostname: %s\r\n",
		    strerror(errno));
        else {
#if defined(_AIX)
		sprintf(banner, "\r\n    %%h (%s release %s.%s) (%%t)\r\n\r\n",
		    name.sysname, name.version, name.release);
#else
		sprintf(banner, "\r\n    %%h (%s release %s %s) (%%t)\r\n\r\n",
		    name.sysname, name.release, name.version);
#endif
	}
	return banner;
}

int
main(argc, argv)
	int argc;
	char *argv[];
{
	struct sockaddr_storage from;
	int on = 1;
	socklen_t fromlen;
	register int ch;
	extern char *optarg;
	extern int optind;
#if	defined(IPPROTO_IP) && defined(IP_TOS)
	int tos = -1;
#endif

	pfrontp = pbackp = ptyobuf;
	netip = netibuf;
	nfrontp = nbackp = netobuf;
#ifdef	ENCRYPTION
	nclearto = 0;
#endif	/* ENCRYPTION */

	progname = *argv;

#ifdef CRAY
	/*
	 * Get number of pty's before trying to process options,
	 * which may include changing pty range.
	 */
	highpty = getnpty();
#endif /* CRAY */

	while ((ch = getopt(argc, argv, valid_opts)) != -1) {
		switch(ch) {

#ifdef	AUTHENTICATION
		case 'a':
			/*
			 * Check for required authentication level
			 */
			if (strcmp(optarg, "debug") == 0) {
				extern int auth_debug_mode;
				auth_debug_mode = 1;
			} else if (strcasecmp(optarg, "none") == 0) {
				auth_level = 0;
			} else if (strcasecmp(optarg, "other") == 0) {
				auth_level = AUTH_OTHER;
			} else if (strcasecmp(optarg, "user") == 0) {
				auth_level = AUTH_USER;
			} else if (strcasecmp(optarg, "valid") == 0) {
				auth_level = AUTH_VALID;
			} else if (strcasecmp(optarg, "off") == 0) {
				/*
				 * This hack turns off authentication
				 */
				auth_level = -1;
			} else {
				fprintf(stderr,
			    "telnetd: unknown authorization level for -a\n");
			}
			break;
#endif	/* AUTHENTICATION */

#ifdef BFTPDAEMON
		case 'B':
			bftpd++;
			break;
#endif /* BFTPDAEMON */

		case 'd':
			if (strcmp(optarg, "ebug") == 0) {
				debug++;
				break;
			}
			usage();
			/* NOTREACHED */
			break;

#ifdef DIAGNOSTICS
		case 'D':
			/*
			 * Check for desired diagnostics capabilities.
			 */
			if (!strcmp(optarg, "report")) {
				diagnostic |= TD_REPORT|TD_OPTIONS;
			} else if (!strcmp(optarg, "exercise")) {
				diagnostic |= TD_EXERCISE;
			} else if (!strcmp(optarg, "netdata")) {
				diagnostic |= TD_NETDATA;
			} else if (!strcmp(optarg, "ptydata")) {
				diagnostic |= TD_PTYDATA;
			} else if (!strcmp(optarg, "options")) {
				diagnostic |= TD_OPTIONS;
			} else if (!strcmp(optarg, "encrypt")) {
				extern int encrypt_debug_mode;
				encrypt_debug_mode = 1;
			} else {
				usage();
				/* NOT REACHED */
			}
			break;
#endif /* DIAGNOSTICS */

#ifdef	ENCRYPTION
		case 'e':
			must_encrypt = 1;
			break;
#endif	/* ENCRYPTION */

		case 'h':
			hostinfo = 0;
			break;

#if	defined(CRAY) && defined(NEWINIT)
		case 'I':
		    {
			extern char *gen_id;
			gen_id = optarg;
			break;
		    }
#endif	/* defined(CRAY) && defined(NEWINIT) */

#ifdef	LINEMODE
		case 'l':
			alwayslinemode = 1;
			break;
#endif	/* LINEMODE */

		case 'k':
#if	defined(LINEMODE) && defined(KLUDGELINEMODE)
			lmodetype = NO_AUTOKLUDGE;
#else
			/* ignore -k option if built without kludge linemode */
#endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
			break;

		case 'L':
		    {
		        extern char *login_program;

			login_program = optarg;
			break;
		    }

		case 'n':
			keepalive = 0;
			break;

#ifdef CRAY
		case 'r':
		    {
			char *strchr();
			char *c;

			/*
			 * Allow the specification of alterations
			 * to the pty search range.  It is legal to
			 * specify only one, and not change the
			 * other from its default.
			 */
			c = strchr(optarg, '-');
			if (c) {
				*c++ = '\0';
				highpty = atoi(c);
			}
			if (*optarg != '\0')
				lowpty = atoi(optarg);
			if ((lowpty > highpty) || (lowpty < 0) ||
							(highpty > 32767)) {
				usage();
				/* NOT REACHED */
			}
			break;
		    }
#endif	/* CRAY */

#ifdef KRB5
		case 'R':
		    {
			extern krb5_context telnet_context;
			krb5_error_code retval;
			
			if (telnet_context == 0) {
				retval = krb5_init_context(&telnet_context);
				if (retval) {
					com_err("telnetd", retval,
						"while initializing krb5");
					exit(1);
				}
			}
			krb5_set_default_realm(telnet_context, optarg);
			break;
		    }
#endif	/* KRB5 */

#ifdef	SecurID
		case 's':
			/* SecurID required */
			require_SecurID = 1;
			break;
#endif	/* SecurID */
		case 'S':
#ifdef	HAVE_GETTOSBYNAME
			if ((tos = parsetos(optarg, "tcp")) < 0)
				fprintf(stderr, "%s%s%s\n",
					"telnetd: Bad TOS argument '", optarg,
					"'; will try to use default TOS");
#else
			fprintf(stderr, "%s%s\n", "TOS option unavailable; ",
						"-S flag not supported\n");
#endif
			break;

#ifdef KRB5
		case 't':
		    {
			extern char *telnet_srvtab;

			telnet_srvtab = optarg;
			break;
		    }
#endif	/* KRB5 */


		case 'U':
			registerd_host_only = 1;
			break;

#ifdef	AUTHENTICATION
		case 'X':
			/*
			 * Check for invalid authentication types
			 */
			auth_disable_name(optarg);
			break;
#endif	/* AUTHENTICATION */
		case 'w':
			if (!strcmp(optarg, "ip"))
				always_ip = 1;
			else {
				char *cp;
				cp = strchr(optarg, ',');
				if (cp == NULL)
					maxhostlen = atoi(optarg);
				else if (*(++cp)) {
					if (!strcmp(cp, "striplocal"))
						stripdomain = 1;
					else if (!strcmp(cp, "nostriplocal"))
						stripdomain = 0;
					else {
						usage();
					}
					*(--cp) = '\0';
					maxhostlen = atoi(optarg);
				}
			}
			break;
		default:
			fprintf(stderr, "telnetd: %c: unknown option\n", ch);
			/* FALLTHROUGH */
		case '?':
			usage();
			/* NOTREACHED */
		}
	}

	argc -= optind;
	argv += optind;

	/* XXX Convert this to support getaddrinfo, ipv6, etc.  */
	if (debug) {
	    int s, ns;
	    socklen_t foo;
	    struct servent *sp;
	    static struct sockaddr_in sin4 = { AF_INET };

	    if (argc > 1) {
		usage();
		/* NOT REACHED */
	    } else if (argc == 1) {
		    if ((sp = getservbyname(*argv, "tcp"))) {
			sin4.sin_port = sp->s_port;
		    } else {
			sin4.sin_port = atoi(*argv);
			if ((int)sin4.sin_port <= 0) {
			    fprintf(stderr, "telnetd: %s: bad port #\n", *argv);
			    usage();
			    /* NOT REACHED */
			}
			sin4.sin_port = htons((u_short)sin4.sin_port);
		   }
	    } else {
		sp = getservbyname("telnet", "tcp");
		if (sp == 0) {
		    fprintf(stderr, "telnetd: tcp/telnet: unknown service\n");
		    exit(1);
		}
		sin4.sin_port = sp->s_port;
	    }

	    s = socket(AF_INET, SOCK_STREAM, 0);
	    if (s < 0) {
		    perror("telnetd: socket");;
		    exit(1);
	    }
	    (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
				(char *)&on, sizeof(on));
	    if (bind(s, (struct sockaddr *)&sin4, sizeof(sin4)) < 0) {
		perror("bind");
		exit(1);
	    }
	    if (listen(s, 1) < 0) {
		perror("listen");
		exit(1);
	    }
	    foo = sizeof(sin4);
	    ns = accept(s, (struct sockaddr *)&sin4, &foo);
	    if (ns < 0) {
		perror("accept");
		exit(1);
	    }
	    (void) dup2(ns, 0);
	    (void) close(ns);
	    (void) close(s);
#ifdef convex
	} else if (argc == 1) {
		; /* VOID*/		/* Just ignore the host/port name */
#endif
	} else if (argc > 0) {
		usage();
		/* NOT REACHED */
	}

#if	defined(_SC_CRAY_SECURE_SYS)
	secflag = sysconf(_SC_CRAY_SECURE_SYS);

	/*
	 *	Get socket's security label
	 */
	if (secflag)  {
		int szss = sizeof(ss);
#ifdef SO_SEC_MULTI			/* 8.0 code */
		int sock_multi;
		int szi = sizeof(int);
#endif /* SO_SEC_MULTI */

		memset((char *)&dv, 0, sizeof(dv));

		if (getsysv(&sysv, sizeof(struct sysv)) != 0) {
			perror("getsysv");
			exit(1);
		}

		/*
		 *	Get socket security label and set device values
		 *	   {security label to be set on ttyp device}
		 */
#ifdef SO_SEC_MULTI			/* 8.0 code */
		if ((getsockopt(0, SOL_SOCKET, SO_SECURITY,
			       (char *)&ss, &szss) < 0) ||
		    (getsockopt(0, SOL_SOCKET, SO_SEC_MULTI,
				(char *)&sock_multi, &szi) < 0)) {
			perror("getsockopt");
			exit(1);
		} else {
			dv.dv_actlvl = ss.ss_actlabel.lt_level;
			dv.dv_actcmp = ss.ss_actlabel.lt_compart;
			if (!sock_multi) {
				dv.dv_minlvl = dv.dv_maxlvl = dv.dv_actlvl;
				dv.dv_valcmp = dv.dv_actcmp;
			} else {
				dv.dv_minlvl = ss.ss_minlabel.lt_level;
				dv.dv_maxlvl = ss.ss_maxlabel.lt_level;
				dv.dv_valcmp = ss.ss_maxlabel.lt_compart;
			}
			dv.dv_devflg = 0;
		}
#else /* SO_SEC_MULTI */		/* 7.0 code */
		if (getsockopt(0, SOL_SOCKET, SO_SECURITY,
				(char *)&ss, &szss) >= 0) {
			dv.dv_actlvl = ss.ss_slevel;
			dv.dv_actcmp = ss.ss_compart;
			dv.dv_minlvl = ss.ss_minlvl;
			dv.dv_maxlvl = ss.ss_maxlvl;
			dv.dv_valcmp = ss.ss_maxcmp;
		}
#endif /* SO_SEC_MULTI */
	}
#endif	/* _SC_CRAY_SECURE_SYS */

	openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
	fromlen = sizeof (from);
	memset(&from, 0, sizeof(from));
	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
		fprintf(stderr, "%s: ", progname);
		perror("getpeername");
		_exit(1);
	}
	if (keepalive &&
	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE,
			(char *)&on, sizeof (on)) < 0) {
		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
	}

#if	defined(IPPROTO_IP) && defined(IP_TOS)
	if (fromlen == sizeof (struct in_addr)) {
# if	defined(HAVE_GETTOSBYNAME)
		struct tosent *tp;
		if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
			tos = tp->t_tos;
# endif
		if (tos < 0)
			tos = 020;	/* Low Delay bit */
		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((struct sockaddr *)&from);
	
	/* NOTREACHED */
	return 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	HAVE_GETTOSBYNAME
	fprintf(stderr, " [-S tos]");
#endif
#ifdef	AUTHENTICATION
	fprintf(stderr, " [-X auth-type]");
#endif
	fprintf(stderr, " [-U]\n\t");
	fprintf(stderr, " [-w [ip|maxhostlen[,[no]striplocal]]]\n\t");
	fprintf(stderr, " [port]\n");
	exit(1);
}

static void encrypt_failure()
{
    char *lerror_message;

    if (auth_must_encrypt())
	lerror_message = "Encryption was not successfully negotiated.  Goodbye.\r\n\r\n";
    else
	lerror_message = "Unencrypted connection refused. Goodbye.\r\n\r\n";

    netputs(lerror_message);
    netflush();
    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
};

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

    settimer(baseline);
#if	defined(AUTHENTICATION)
    ttsuck();
    /*
     * 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)) {
	auth_wait(name);
    }
#endif

#ifdef	ENCRYPTION
    send_will(TELOPT_ENCRYPT, 1);
    send_do(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) ||
	   his_will_wont_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();
    }
    if (must_encrypt || auth_must_encrypt()) {
	time_t timeout = time(0) + 60;
	
	if (my_state_is_dont(TELOPT_ENCRYPT) ||
	    my_state_is_wont(TELOPT_ENCRYPT) ||
	    his_state_is_wont(TELOPT_AUTHENTICATION))
	    encrypt_failure();

	while (!EncryptStartInput()) {
	    if (time (0) > timeout)
		encrypt_failure();
	    ttloop();
	}

	while (!EncryptStartOutput()) {
	    if (time (0) > timeout)
		encrypt_failure();
	    ttloop();
	}

	while (!encrypt_is_encrypting()) {
	    if (time(0) > timeout)
		encrypt_failure();
	    ttloop();
	}
    }
#endif	/* ENCRYPTION */
    /* Options like environment require authentication and encryption
       negotiation to be completed.*/
    auth_negotiated = 1;
    if (his_state_is_will(TELOPT_TSPEED)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };
	netwrite(sb, sizeof(sb));
    }
    if (his_state_is_will(TELOPT_XDISPLOC)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
	netwrite(sb, sizeof(sb));
    }
    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };
	netwrite(sb, sizeof(sb));
    }
    else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
	static unsigned char sb[] =
			{ IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };
	netwrite(sb, sizeof(sb));
    }
    if (his_state_is_will(TELOPT_TTYPE))
	netwrite(ttytype_sbbuf, sizeof(ttytype_sbbuf));

    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) - 1);
	    first[sizeof(first) - 1] = '\0';
	    for(;;) {
		/*
		 * Save the unknown name, and request the next name.
		 */
		(void) strncpy(last, terminaltype, sizeof(last) - 1);
		last[sizeof(last) - 1] = '\0';
		_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(terminaltype) - 1);
			terminaltype[sizeof(terminaltype) - 1] = '\0';
		    }
		    break;
		}
	    }
	}
    }
#ifdef AUTHENTICATION
    return(auth_check(name));
#else
    return(-1);
#endif
}  /* end of getterminaltype */

static 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);
    netwrite(ttytype_sbbuf, sizeof(ttytype_sbbuf));
    while (sequenceIs(ttypesubopt, baseline))
	ttloop();
}

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

    if (!*s)
	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);
}
#if HAVE_ARPA_NAMESER_H
#include <arpa/nameser.h>
#endif

#ifndef MAXDNAME
#define MAXDNAME 256 /*per the rfc*/
#endif

char *hostname;
char host_name[MAXDNAME];
char remote_host_name[MAXDNAME];
char *rhost_sane;

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

/*
 * Get a pty, scan input lines.
 */
static void doit(who)
	struct sockaddr *who;
{
	int level;
#if	defined(_SC_CRAY_SECURE_SYS)
	int ptynum;
#endif
	char user_name[256];
	long retval;
	/*
	 * Find an available pty to use.
	 */
	pty_init();
	

	if ((retval = pty_getpty(&pty, line, 17)) != 0) {
		fatal(net, error_message(retval));
	}

#if	defined(_SC_CRAY_SECURE_SYS)
	/*
	 *	set ttyp line security label 
	 */
	if (secflag) {
		char slave_dev[16];
/*xxx This code needs to be fixed to work without ptynum; I don't understand why they don't currently use line, so I don't really know how to fix.*/
		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 */

	retval = pty_make_sane_hostname((struct sockaddr *) who, maxhostlen,
					stripdomain, always_ip,
					&rhost_sane);
	if (retval) {
		fatal(net, error_message(retval));
	}
	if (registerd_host_only) {
	    /* Get name of connected client -- but we don't actually
	       use it.  Just confirm that we can get it.  */
	    int aierror;
	    char hostnamebuf[NI_MAXHOST];
	    aierror = getnameinfo (who, socklen (who),
				   hostnamebuf, sizeof (hostnamebuf), 0, 0,
				   NI_NAMEREQD);
	    if (aierror != 0) {
		fatal(net,
		      "Couldn't resolve your address into a host name.\r\n"
		      "Please contact your net administrator");
	    }
	}

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

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

	init_env();

#ifdef	SIGTTOU
	/*
	 * Ignoring SIGTTOU keeps the kernel from blocking us.
	 * we tweak the tty with an ioctl()
	 * (in ttioct() in /sys/tty.c in a BSD kernel)
	 */
	(void) signal(SIGTTOU, SIG_IGN);
#endif
	/*
	 * get terminal type.
	 */
	*user_name = 0;
	level = getterminaltype(user_name);
	setenv("TERM", *terminaltype ? terminaltype : "network", 1);

#if defined (AUTHENTICATION)
	if (level < 0 && auth_level > 0) {
		fatal (net, "No authentication provided");
		exit (-1);
	}
#endif
	/*
	 * Start up the login process on the slave side of the terminal
	 */
#ifndef	convex
	startslave(rhost_sane, 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, rhost_sane);
#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 *HEstr;
	char *HN;
	char *IM;
	void netflush();

	/*
	 * 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, netputs("td: simulating recv\r\n"));
		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)
	init_termdriver(f, p, interrupt, sendbrk);
#endif

#if	defined(SO_OOBINLINE)
	(void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
				(char *)&on, sizeof(on));
#endif	/* defined(SO_OOBINLINE) */

#ifdef	SIGTSTP
	(void) signal(SIGTSTP, SIG_IGN);
#endif

	(void) signal(SIGCHLD, cleanup);

#if	defined(CRAY2) && defined(UNICOS5)
	/*
	 * Cray-2 will send a signal when pty modes are changed by slave
	 * side.  Set up signal handler now.
	 */
	if ((int)signal(SIGUSR1, termstat) < 0)
		perror("signal");
	else if (ioctl(p, TCSIGME, (char *)SIGUSR1) < 0)
		perror("ioctl:TCSIGME");
	/*
	 * Make processing loop check terminal characteristics early on.
	 */
	termstat();
#endif

#ifdef  TIOCNOTTY
	{
		register int t;
		t = open(_PATH_TTY, O_RDWR);
		if (t >= 0) {
			(void) ioctl(t, TIOCNOTTY, (char *)0);
			(void) close(t);
		}
	}
#endif

#if	defined(CRAY) && defined(NEWINIT) && defined(TIOCSCTTY)
	(void) setsid();
	ioctl(p, TIOCSCTTY, 0);
#endif

	/*
	 * Show banner that getty never gave.
	 *
	 * We put the banner in the pty input buffer.  This way, it
	 * gets carriage return null processing, etc., just like all
	 * other pty --> client data.
	 */

#if	!defined(CRAY) || !defined(NEWINIT)
	if (getenv("USER"))
		hostinfo = 0;
#endif

	if (getent(defent, "default") == 1) {
		char *getstr();
		char *cp=defstrs;

		HEstr = getstr("he", &cp);
		HN = getstr("hn", &cp);
		IM = getstr("im", &cp);
		if (HN && *HN)
			(void) strncpy(host_name, HN, sizeof(host_name) - 1);
		host_name[sizeof(host_name) - 1] = '\0';
		if (IM == 0)
			IM = "";
	} else {
		IM = get_default_IM();
		HEstr = 0;
	}
	edithost(HEstr, host_name);
	if (hostinfo && *IM)
		putf(IM, ptyibuf2);

	if (pcc)
		(void) strncat(ptyibuf2, ptyip, pcc+1);
	ptyip = ptyibuf2;
	pcc = strlen(ptyip);
#ifdef	LINEMODE
	/*
	 * Last check to make sure all our states are correct.
	 */
	init_termbuf();
	localstat();
#endif	/* LINEMODE */

	DIAG(TD_REPORT, netputs("td: Entering processing loop\r\n"));

#ifdef	convex
	startslave(host);
#endif

	for (;;) {
		fd_set ibits, obits, xbits;
		register int c;

		if (ncc < 0 && pcc < 0)
			break;

#if	defined(CRAY2) && defined(UNICOS5)
		if (needtermstat)
			_termstat();
#endif	/* defined(CRAY2) && defined(UNICOS5) */
		FD_ZERO(&ibits);
		FD_ZERO(&obits);
		FD_ZERO(&xbits);
		/*
		 * Never look for input if there's still
		 * stuff in the corresponding output buffer
		 */
		if (nfrontp - nbackp || pcc > 0) {
			FD_SET(f, &obits);
		} else {
			FD_SET(p, &ibits);
		}
		if (pfrontp - pbackp || ncc > 0) {
			FD_SET(p, &obits);
		} else {
			FD_SET(f, &ibits);
		}
		if (!SYNCHing) {
			FD_SET(f, &xbits);
		}
		if ((c = select(16, &ibits, &obits, &xbits,
						(struct timeval *)0)) < 1) {
			if (c == -1) {
				if (errno == EINTR) {
					continue;
				}
			}
			sleep(5);
			continue;
		}

		/*
		 * Any urgent data?
		 */
		if (FD_ISSET(net, &xbits)) {
		    SYNCHing = 1;
		}

		/*
		 * Something to read from the network...
		 */
		if (FD_ISSET(net, &ibits)) {
#if	!defined(SO_OOBINLINE)
			/*
			 * In 4.2 (and 4.3 beta) systems, the
			 * OOB indication and data handling in the kernel
			 * is such that if two separate TCP Urgent requests
			 * come in, one byte of TCP data will be overlaid.
			 * This is fatal for Telnet, but we try to live
			 * with it.
			 *
			 * In addition, in 4.2 (and...), a special protocol
			 * is needed to pick up the TCP Urgent data in
			 * the correct sequence.
			 *
			 * What we do is:  if we think we are in urgent
			 * mode, we look to see if we are "at the mark".
			 * If we are, we do an OOB receive.  If we run
			 * this twice, we will do the OOB receive twice,
			 * but the second will fail, since the second
			 * time we were "at the mark", but there wasn't
			 * any data there (the kernel doesn't reset
			 * "at the mark" until we do a normal read).
			 * Once we've read the OOB data, we go ahead
			 * and do normal reads.
			 *
			 * There is also another problem, which is that
			 * since the OOB byte we read doesn't put us
			 * out of OOB state, and since that byte is most
			 * likely the TELNET DM (data mark), we would
			 * stay in the TELNET SYNCH (SYNCHing) state.
			 * So, clocks to the rescue.  If we've "just"
			 * received a DM, then we test for the
			 * presence of OOB data when the receive OOB
			 * fails (and AFTER we did the normal mode read
			 * to clear "at the mark").
			 */
		    if (SYNCHing) {
			int atmark;

			(void) ioctl(net, SIOCATMARK, (char *)&atmark);
			if (atmark) {
			    ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
			    if ((ncc == -1) && (errno == EINVAL)) {
				ncc = read(net, netibuf, sizeof (netibuf));
				if (sequenceIs(didnetreceive, gotDM)) {
				    SYNCHing = stilloob(net);
				}
			    }
			} else {
			    ncc = read(net, netibuf, sizeof (netibuf));
			}
		    } else {
			ncc = read(net, netibuf, sizeof (netibuf));
		    }
		    settimer(didnetreceive);
#else	/* !defined(SO_OOBINLINE)) */
		    ncc = read(net, netibuf, sizeof (netibuf));
#endif	/* !defined(SO_OOBINLINE)) */
		    if (ncc < 0 && errno == EWOULDBLOCK)
			ncc = 0;
		    else {
			if (ncc <= 0) {
			    break;
			}
			netip = netibuf;
		    }
		    DIAG((TD_REPORT | TD_NETDATA),
			 netprintf("td: netread %d chars\r\n", ncc));
		    DIAG(TD_NETDATA, printdata("nd", netip, ncc));
		}

		/*
		 * Something to read from the pty...
		 */
		if (FD_ISSET(p, &ibits)) {
#ifndef	STREAMSPTY
			pcc = read(p, ptyibuf, BUFSIZ);
#else
			pcc = readstream(p, ptyibuf, BUFSIZ);
#endif
			/*
			 * On some systems, if we try to read something
			 * off the master side before the slave side is
			 * opened, we get EIO.
			 */
			if (pcc < 0 && (errno == EWOULDBLOCK ||
#ifdef	EAGAIN
					errno == EAGAIN ||
#endif
					errno == EIO)) {
				pcc = 0;
			} else {
				if (pcc <= 0)
					break;
#if	!defined(CRAY2) || !defined(UNICOS5)
#ifdef	LINEMODE
				/*
				 * If ioctl from pty, pass it through net
				 */
				if (ptyibuf[0] & TIOCPKT_IOCTL) {
					copy_termbuf(ptyibuf+1, pcc-1);
					localstat();
					pcc = 1;
				}
#endif	/* LINEMODE */
				if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
					netclear();	/* clear buffer back */
#ifndef	NO_URGENT
					/*
					 * There are client telnets on some
					 * operating systems get screwed up
					 * royally if we send them urgent
					 * mode data.
					 */
					netprintf_urg("%c%c", IAC, DM);
#endif
				}
				if (his_state_is_will(TELOPT_LFLOW) &&
				    (ptyibuf[0] &
				     (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
					int newflow =
					    ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
					if (newflow != flowmode) {
						flowmode = newflow;
						netprintf("%c%c%c%c%c%c",
							IAC, SB, TELOPT_LFLOW,
							flowmode ? LFLOW_ON
								 : LFLOW_OFF,
							IAC, SE);
					}
				}
				pcc--;
				ptyip = ptyibuf+1;
#else	/* defined(CRAY2) && defined(UNICOS5) */
				if (!uselinemode) {
					unpcc = pcc;
					unptyip = ptyibuf;
					pcc = term_output(&unptyip, ptyibuf2,
								&unpcc, BUFSIZ);
					ptyip = ptyibuf2;
				} else
					ptyip = ptyibuf;
#endif	/* defined(CRAY2) && defined(UNICOS5) */
			}
		}

		while (pcc > 0) {
			if ((&netobuf[BUFSIZ] - nfrontp) < 2)
				break;
			c = *ptyip++ & 0377, pcc--;
			if (c == IAC)
				netprintf("%c", c);
#if	defined(CRAY2) && defined(UNICOS5)
			else if (c == '\n' &&
				     my_state_is_wont(TELOPT_BINARY) && newmap)
				netputs("\r");
#endif	/* defined(CRAY2) && defined(UNICOS5) */
			netprintf("%c", c);
			if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
				if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
					netprintf("%c", *ptyip++ & 0377);
					pcc--;
				} else
					netprintf("%c", '\0');
			}
		}
#if	defined(CRAY2) && defined(UNICOS5)
		/*
		 * If chars were left over from the terminal driver,
		 * note their existence.
		 */
		if (!uselinemode && unpcc) {
			pcc = unpcc;
			unpcc = 0;
			ptyip = unptyip;
		}
#endif	/* defined(CRAY2) && defined(UNICOS5) */

		if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
			netflush();
		if (ncc > 0)
			telrcv();
		if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
			ptyflush();
	}
	(void) signal(SIGCHLD, SIG_DFL);
	cleanup(0);
}  /* end of telnet */
	
#ifndef	TCSIG
# ifdef	TIOCSIG
#  define TCSIG TIOCSIG
# endif
#endif

#ifdef	STREAMSPTY

int flowison = -1;  /* current state of flow: -1 is unknown */

int readstream(p, ibuf, bufsize)
	int p;
	char *ibuf;
	int bufsize;
{
	int flags = 0;
	int ret = 0;
	struct termios *tsp;
	struct termio *tp;
	struct iocblk *ip;
	char vstop, vstart;
	int ixon;
	int newflow;

	strbufc.maxlen = BUFSIZ;
	strbufc.buf = (char *)ctlbuf;
	strbufd.maxlen = bufsize-1;
	strbufd.len = 0;
	strbufd.buf = ibuf+1;
	ibuf[0] = 0;

	ret = getmsg(p, &strbufc, &strbufd, &flags);
	if (ret < 0)  /* error of some sort -- probably EAGAIN */
		return(-1);

	if (strbufc.len <= 0 || ctlbuf[0] == M_DATA) {
		/* data message */
		if (strbufd.len > 0) {			/* real data */
			return(strbufd.len + 1);	/* count header char */
		} else {
			/* nothing there */
			errno = EAGAIN;
			return(-1);
		}
	}

	/*
	 * It's a control message.  Return 1, to look at the flag we set
	 */

	switch (ctlbuf[0]) {
	case M_FLUSH:
		if (ibuf[1] & FLUSHW)
			ibuf[0] = TIOCPKT_FLUSHWRITE;
		return(1);

	case M_IOCTL:
		ip = (struct iocblk *) (ibuf+1);
		if (readstream_termio(ip->ioc_cmd, ibuf, 
				      &vstop, &vstart, &ixon)) {
		  if (readstream_termios(ip->ioc_cmd, ibuf, 
					 &vstop, &vstart, &ixon)) {
		    errno = EAGAIN;
		    return(-1);
		  }
		}

		newflow =  (ixon && (vstart == 021) && (vstop == 023)) ? 1 : 0;
		if (newflow != flowison) {  /* it's a change */
			flowison = newflow;
			ibuf[0] = newflow ? TIOCPKT_DOSTOP : TIOCPKT_NOSTOP;
			return(1);
		}
	}

	/* nothing worth doing anything about */
	errno = EAGAIN;
	return(-1);
}
#endif /* STREAMSPTY */

/*
 * Send interrupt to process on other side of pty.
 * If it is in raw mode, just write NULL;
 * otherwise, write intr char.
 */
	void
interrupt()
{
	ptyflush();	/* half-hearted */

#ifdef	TCSIG
	(void) ioctl(pty, TCSIG, (char *)SIGINT);
#else	/* TCSIG */
	init_termbuf();
	*pfrontp++ = slctab[SLC_IP].sptr ?
			(unsigned char)*slctab[SLC_IP].sptr : '\177';
#endif	/* TCSIG */
}

/*
 * Send quit to process on other side of pty.
 * If it is in raw mode, just write NULL;
 * otherwise, write quit char.
 */
	void
sendbrk()
{
	ptyflush();	/* half-hearted */
#ifdef	TCSIG
	(void) ioctl(pty, TCSIG, (char *)SIGQUIT);
#else	/* TCSIG */
	init_termbuf();
	*pfrontp++ = slctab[SLC_ABORT].sptr ?
			(unsigned char)*slctab[SLC_ABORT].sptr : '\034';
#endif	/* TCSIG */
}

	void
sendsusp()
{
#ifdef	SIGTSTP
	ptyflush();	/* half-hearted */
# ifdef	TCSIG
	(void) ioctl(pty, TCSIG, (char *)SIGTSTP);
# else	/* TCSIG */
	*pfrontp++ = slctab[SLC_SUSP].sptr ?
			(unsigned char)*slctab[SLC_SUSP].sptr : '\032';
# endif	/* TCSIG */
#endif	/* SIGTSTP */
}

/*
 * When we get an AYT, if ^T is enabled, use that.  Otherwise,
 * just send back "[Yes]".
 */
void
recv_ayt()
{
#if	defined(SIGINFO) && defined(TCSIG)
	if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
		(void) ioctl(pty, TCSIG, (char *)SIGINFO);
		return;
	}
#endif
	netputs("\r\n[Yes]\r\n");
}

	void
doeof()
{
	init_termbuf();

#if	defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN)
	if (!tty_isediting()) {
		extern char oldeofc;
		*pfrontp++ = oldeofc;
		return;
	}
#endif
	*pfrontp++ = slctab[SLC_EOF].sptr ?
			(unsigned char)*slctab[SLC_EOF].sptr : '\004';
}