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deb-mbse/mbcico/telnet.c

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/*****************************************************************************
*
* $Id$
* Purpose ...............: Fidonet mailer
*
*****************************************************************************
* Copyright (C) 1997-2004
*
* Michiel Broek FIDO: 2:280/2802
* Beekmansbos 10
* 1971 BV IJmuiden
* the Netherlands
*
* This file is part of MBSE BBS.
*
* This BBS is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* MBSE BBS is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with MBSE BBS; see the file COPYING. If not, write to the Free
* Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*****************************************************************************/
#include "../config.h"
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#include "../lib/mbselib.h"
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#include "telnet.h"
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/*
* Telnet I/O filters. See RFC854 for details.
*/
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/*
* Send options to the remote.
*/
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void telnet_init(int Fd)
{
Syslog('s', "telnet_init(%d)", Fd);
telnet_answer(DO, TOPT_SUPP, Fd);
telnet_answer(WILL, TOPT_SUPP, Fd);
telnet_answer(DO, TOPT_BIN, Fd);
telnet_answer(WILL, TOPT_BIN, Fd);
telnet_answer(DO, TOPT_ECHO, Fd);
telnet_answer(WILL, TOPT_ECHO, Fd);
}
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/*
* Answer options requested by remote.
*/
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void telnet_answer(int tag, int opt, int Fd)
{
char buf[3];
char *r = (char *)"???";
switch (tag) {
case WILL: r = (char *)"WILL";
break;
case WONT: r = (char *)"WONT";
break;
case DO: r = (char *)"DO";
break;
case DONT: r = (char *)"DONT";
break;
}
Syslog('s', "Telnet: send %s %d", r, opt);
buf[0] = IAC;
buf[1] = tag;
buf[2] = opt;
if (write (Fd, buf, 3) != 3)
WriteError("$answer cant send");
}
/*
* Telnet output filter, escape IAC.
*/
void telout_filter(int fdi, int fdo)
{
int rc, c;
char ch;
Syslog('s', "telout_filter: in=%d out=%d", fdi, fdo);
while ((rc = read(fdi, &ch, 1)) > 0) {
c = (int)ch & 0xff;
if (c == IAC) {
/*
* Escape IAC characters by sending it twice.
*/
rc = write(fdo, &ch, 1);
}
if ((rc = write(fdo, &ch, 1)) == -1) {
Syslog('s', "$telout_filter: write failed");
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exit(MBERR_TTYIO_ERROR);
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}
}
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Syslog('s', "telout_filter: finished rc=%d", rc);
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exit(0);
}
/*
* Telnet input filter, interpret telnet commands.
*/
void telin_filter(int fdo, int fdi)
{
int rc, c, m;
char ch;
Syslog('s', "telin_filter: in=%d out=%d", fdi, fdo);
while ((rc = read(fdi, &ch, 1)) > 0) {
c = (int)ch & 0xff;
if (c == IAC) {
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if ((read(fdi, &ch, 1) < 0))
break;
m = (int)ch & 0xff;
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switch (m) {
case WILL: read(fdi, &ch, 1);
m = (int)ch & 0xff;
Syslog('s', "Telnet: recv WILL %d", m);
if (m != TOPT_BIN && m != TOPT_SUPP && m != TOPT_ECHO)
telnet_answer(DONT, m, fdo);
break;
case WONT: read(fdi, &ch, 1);
m = (int)ch & 0xff;
Syslog('s', "Telnet: recv WONT %d", m);
break;
case DO: read(fdi, &ch, 1);
m = (int)ch & 0xff;
Syslog('s', "Telnet: recv DO %d", m);
if (m != TOPT_BIN && m != TOPT_SUPP && m != TOPT_ECHO)
telnet_answer(WONT, m, fdo);
break;
case DONT: read(fdi, &ch, 1);
m = (int)ch & 0xff;
Syslog('s', "Telnet: recv DONT %d", m);
break;
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case IAC: ch = (char)m;
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rc = write(fdo, &ch, 1);
break;
default: Syslog('s', "Telnet: recv IAC %d, not good", m);
break;
}
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} else {
ch = (char)c;
if ((rc = write(fdo, &ch, 1)) == -1) {
Syslog('s', "$telin_filter: write failed");
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exit(MBERR_TTYIO_ERROR);
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}
}
}
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Syslog('s', "telin_filter: finished rc=%d", rc);
exit(0);
}