177 lines
4.1 KiB
C
177 lines
4.1 KiB
C
/*****************************************************************************
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*
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* $Id: telnet.c,v 1.6 2004/02/21 17:22:01 mbroek Exp $
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* Purpose ...............: Fidonet mailer
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*
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*****************************************************************************
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* Copyright (C) 1997-2004
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*
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* Michiel Broek FIDO: 2:280/2802
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* Beekmansbos 10
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* 1971 BV IJmuiden
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* the Netherlands
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*
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* This file is part of MBSE BBS.
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*
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* This BBS is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* MBSE BBS is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with MBSE BBS; see the file COPYING. If not, write to the Free
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* Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*****************************************************************************/
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#include "../config.h"
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#include "../lib/mbselib.h"
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#include "telnet.h"
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/*
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* Telnet I/O filters. See RFC854 for details.
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*/
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/*
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* Send options to the remote.
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*/
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void telnet_init(int Fd)
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{
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Syslog('s', "telnet_init(%d)", Fd);
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telnet_answer(DO, TOPT_SUPP, Fd);
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telnet_answer(WILL, TOPT_SUPP, Fd);
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telnet_answer(DO, TOPT_BIN, Fd);
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telnet_answer(WILL, TOPT_BIN, Fd);
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telnet_answer(DO, TOPT_ECHO, Fd);
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telnet_answer(WILL, TOPT_ECHO, Fd);
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}
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/*
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* Answer options requested by remote.
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*/
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void telnet_answer(int tag, int opt, int Fd)
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{
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char buf[3];
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char *r = (char *)"???";
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switch (tag) {
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case WILL: r = (char *)"WILL";
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break;
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case WONT: r = (char *)"WONT";
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break;
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case DO: r = (char *)"DO";
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break;
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case DONT: r = (char *)"DONT";
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break;
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}
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Syslog('s', "Telnet: send %s %d", r, opt);
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buf[0] = IAC;
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buf[1] = tag;
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buf[2] = opt;
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if (write (Fd, buf, 3) != 3)
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WriteError("$answer cant send");
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}
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/*
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* Telnet output filter, escape IAC.
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*/
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void telout_filter(int fdi, int fdo)
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{
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int rc, c;
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char ch;
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Syslog('s', "telout_filter: in=%d out=%d", fdi, fdo);
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while ((rc = read(fdi, &ch, 1)) > 0) {
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c = (int)ch & 0xff;
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if (c == IAC) {
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/*
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* Escape IAC characters by sending it twice.
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*/
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rc = write(fdo, &ch, 1);
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}
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if ((rc = write(fdo, &ch, 1)) == -1) {
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Syslog('s', "$telout_filter: write failed");
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exit(MBERR_TTYIO_ERROR);
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}
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}
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Syslog('s', "telout_filter: finished rc=%d", rc);
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exit(0);
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}
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/*
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* Telnet input filter, interpret telnet commands.
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*/
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void telin_filter(int fdo, int fdi)
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{
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int rc, c, m;
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char ch;
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Syslog('s', "telin_filter: in=%d out=%d", fdi, fdo);
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while ((rc = read(fdi, &ch, 1)) > 0) {
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c = (int)ch & 0xff;
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if (c == IAC) {
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if ((read(fdi, &ch, 1) < 0))
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break;
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m = (int)ch & 0xff;
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switch (m) {
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case WILL: read(fdi, &ch, 1);
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m = (int)ch & 0xff;
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Syslog('s', "Telnet: recv WILL %d", m);
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if (m != TOPT_BIN && m != TOPT_SUPP && m != TOPT_ECHO)
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telnet_answer(DONT, m, fdo);
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break;
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case WONT: read(fdi, &ch, 1);
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m = (int)ch & 0xff;
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Syslog('s', "Telnet: recv WONT %d", m);
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break;
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case DO: read(fdi, &ch, 1);
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m = (int)ch & 0xff;
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Syslog('s', "Telnet: recv DO %d", m);
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if (m != TOPT_BIN && m != TOPT_SUPP && m != TOPT_ECHO)
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telnet_answer(WONT, m, fdo);
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break;
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case DONT: read(fdi, &ch, 1);
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m = (int)ch & 0xff;
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Syslog('s', "Telnet: recv DONT %d", m);
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break;
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case IAC: ch = (char)m;
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rc = write(fdo, &ch, 1);
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break;
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default: Syslog('s', "Telnet: recv IAC %d, not good", m);
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break;
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}
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} else {
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ch = (char)c;
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if ((rc = write(fdo, &ch, 1)) == -1) {
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Syslog('s', "$telin_filter: write failed");
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exit(MBERR_TTYIO_ERROR);
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}
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}
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}
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Syslog('s', "telin_filter: finished rc=%d", rc);
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exit(0);
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}
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