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Text File | 1988-12-19 | 15.9 KB | 444 lines

╔═════════════════════════════════════════════════════════╗ ║ ║ ║ DOSGATE _ ║ ║ \ ║ ║ \ ║ ║ \_ Remote operation of MS-DOS ║ ║ ║ ╚═════════════════════════════════════════════════════════╝ Copyright (c) 1987 Rich Bono, NM1D 7 Redfield Circle Derry, New Hampshire 03038 This document describes DOSGATE version 1.6 DOSGATE is a system which allows an industry standard MS-DOS computer to be controlled via an RS-232 serial port. The port is considered to be a remote user. The traditional console of the machine is still in complete control and can supervise and disable/enable the remote user at will. There is a simple 'Chat' mode that may be entered from the console to allow 'talking' with the remote user to give assistance or instructions. In addition to chat mode, there is a simple terminal emulator to allow control of a modem or other device connected to the serial port. The remote user may be connected directly with an RS-232 terminal, via a modem over telephone lines, or with a TNC for remote operation via radio! The local console may still be used for any software that normally runs. The remote user is capable of running any software that calls only MS-DOS (int 21h) system calls. Any software that by-passes MS-DOS and interfaces with the BIOS or directly with the hardware for I/O will not be usable by the remote user. This version of DOSGATE is being distributed as SHAREWARE. You are allowed to use DOSGATE on a trial basis for a limited period of time. After the trial period, you must register your use of DOSGATE with the author. Remember, DOSGATE is NOT in the public domain, and as such it is NOT free software. If you find DOSGATE helpful in anyway, or you wish to promote further improvements to DOSGATE, please send an apropriate amount to the author at the above address. If you send $20.00 or more, you will be be placed on the update list. The author would like to hear from anyone with comments or suggestions concerning DOSGATE or other projects. Currently tested with : DOS: Versions 3.2, 3.3, 4.00, 4.01 Remote user connection devices: Kantronix KAM (version 2.82 through 2.85) Kantronix KPC-2 (version 2.82 or 2.85) DOSGATE is implemented as an MS-DOS installable device driver. Also implemented is a simple terminal emulator which allows one to communicate with the serial port. To use the terminal emulator, execute DOSGATE at the DOS prompt. The terminal emulator has one command: ALT-X - exits the terminal emulator and returns to MS-DOS. Device driver installation instructions: DOSGATE has but four runtime commands: ALT-D will toggle the remote user on and offline. A message is sent to the console and the remote user to inform about the change. ALT-T will toggle the 'terminal' function on/off. A message is output to confirm the change in mode. This terminal is only to be used for simple configuration commands to or from the TNC or modem. ALT-C will toggle the 'chat' function on/off. A message is output to both the console and the remote user to inform about the change. Use this mode to 'talk' to a remote user that is connected to the system. DOSGATE should be installed as any other MS-DOS device driver. It also provides for various options. CONFIG.SYS should contain the line: DEVICE = DOSGATE.EXE This causes the following default options: Remote user disabled, Remote user with echo, 1200 baud, No handshaking, DOSGATE on COM1, No Carrier Detect logic No SET USER= logic The following options are available at boot time . . . /R - Remote user enabled at boot time /E - Disable ECHO of remote users keystrokes This is useful if the remote users' terminal has local echo. /2 - Selects COM2 for DOSGATE else COM1 is used /C - Carrier Detect logic, will do the following when CD goes TRUE: - Issue CTRL-C, 'START', CR CD goes FALSE: - Issue CTRL-C, 'END', CR Be SURE that your interface cable supports the Carrier Detect Line!!! Remote user must be enabled! This allows the programs 'start' & 'end' to be executed as remote users come and go. /U - Sets the environment variable USER to the ID of the user from the TNC status message. If no TNC status message, user enters CR, and then receives a 'Login:' prompt. The user's input is stored in the USER environment. Note: FORCES the /C switch on (see above). /Bxx - selects baud rate (default is 1200 baud) (No parity, 8 bits, 1 stop bit) currently supported baud rates: /B96 - 9600 baud /B12 - 1200 baud /B30 - 300 baud /B11 - 110 baud /H - Enables hardware handshaking - Must have DSR & CTS to be able to transmit to remote. Be sure that the interface cable supports these lines! /A - Absorb LF's that follow CR's to remote. this is useful if the remote users terminal automatically does a CR/LF upon receiving a CR. /P - Enables Packet radio specific options ie: Remote user enabled at boot time Remote user Echo disabled Absorb LF's following CR's to remote Enable hardware handshaking Carrier detect logic enabled SET USER= logic enabled for example: DEVICE=DOSGATE.EXE /R /E - Start remote user enabled, and absorb (disable) ECHO to the remote user. or DEVICE=DOSGATE.EXE /P - Start DOSGATE for packet radio operation (see '/P' above). DOSGATE should be the only device driver installed for the CON: device. This means DO NOT install an ANSI.SYS device driver when the DOSGATE driver is installed!!! Note: At this time, DOSGATE does not support ANSI escape sequences to the local console. ANSI escape sequence support may be implemented in a later version (Be sure and register if you desire this). Escape sequences will work on a remote terminal if it understands them. It is strongly suggested that you install the DOSGATE driver in a sub-directory that is hidden from the user, and that does NOT have the environment PATH pointing to it. Or you may rename DOSGATE.EXE to DOSGATE.SYS to keep users from executing DOSGATE and invoking the terminal emulator function. When used as a terminal emulator DOSGATE allows the choice of baud rate to be used. ie: DOSGATE /b96 - This would start the terminal emulator using 9600 baud over COM1 (default is 1200 baud). Environment variables are used to assist MS-DOS programs executing in the DOSGATE environment. The currently defined evironment is: USER - Set by DOSGATE driver to the ID of the user. Used by DOSMAIL functions and START.EXE. DRIVES - Used by END.EXE, must be set by AUTOEXEC.BAT Note: The path environment variable should NOT point to a directory that the DOSGATE.EXE driver is stored, and the remote user should NOT be able to stumble across the DOSGATE.EXE file. If the user attempted to execute the DOSGATE driver, he would start the terminal emulator feature of the DOSGATE.EXE driver, and hang the system! Keep the DOSGATE.EXE driver in a hidden directory! The additional programs, "START.EXE", "END.EXE", "DISC.EXE" are used for helping with managing the user in DOSGATE. With this version: START - Can be invoked automatically (see '/C' parameter above). START will: 1: Open the file 'user.log' in the directory specified by the environment 'MSG', and write the contents of the environment 'USER' to that file. 2: Look for a file called "WELCOME.DOC" and output it to the user. This can be to give the user instructions when he first connects. 3: Invoke 'READ /c' to report if the user has any mail. Note: START.EXE can be replaced by a program of your own that performs any functions that you desire to be done when the user first "connects" (see below). END - Can be invoked automatically (see '/C' parameter above). END will look in the environment for the 'DRIVES' parameter. This is used to set each drive to its ROOT ('\') directory, and also to leave the machine with the default drive set as indicated. This is used to insure that the next user will come into DOSGATE at the same place each time, and not where the last user left off. DRIVES should be set in AUTOEXEC.BAT as follows: SET DRIVES=C:;A:;B:;D: This would set each drive (A:, B:, C:, and D:) to its root directory, and also set the default drive to C: (the first drive specified will be the default drive). Note: END.EXE can be replaced by a program that you supply to perform any functions that you desire to happen when the user 'disconnects'. If the 'sysop' desires some other functions to be performed when a user first connects to DOSGATE, just create your own program (or batch file) to perform the desired actions, it must be named START (.EXE, .COM or .BAT). The END (.EXE, .COM, or .BAT) program is called when a user disconnects. This may also be replaced. If the 'sysop' desires nothing to be done for connect/disconnect, and will not be using mail, then the 'CD' logic may be disabled. If the 'sysop' desires connect action, but nothing upon disconnect, then simply replace the END program with one that does nothing. DISC - Must be invoked manually. At this time, DISC will wait 3 seconds, issue 3 control-C's, wait 3 seconds. issue 'DISC' [CR], issue 'TRANS' [CR] This is to place the TNC in command mode, issue a disconnect request, then place the TNC back into TRANSPARENT mode until the disconnect is complete. The user may use this command to have DOSGATE initiate the disconnect. Compatibility with DOSGATE: The general rules for programs that can be run under DOSGATE are fairly simple, not keeping to the rules may simply cause confused users, or could cause the system to HANG! 1 - Any program that affects the serial port that DOSGATE is using for the remote user will probably cause the computer to hang! DOSGATE is using the serial port with interupts ON, and will not tolerate other programs touching the serial port hardware. 2 - Any program that does not do its I/O through DOS (int 21h) calls will by-pass the remote user. This means that the remote user will probably be able to start such a program, and all may appear normal on the local console, but the computer may appear dead as far as the remote user is concerned. 3 - Any program that issues ANSI escape sequences may work for the remote user (if his terminal supports the proper escape sequences), but (with the current version of DOSGATE) will not work correctly on the local console. 4 - Programs that output massive amounts of data may run slow. Remember that any data that is output to the remote user is limited in speed by the serial port, (1200 baud is about 120 characters per second, this means that is will probably take more than 16 seconds to output 1 screen worth of data). 5 - At this time, if the remote user sends too much data to DOSGATE and the current program cannot keep up with the user, some data may be lost. There is output hardware handshaking (CTS). Special notes for TNC users: There are various TNC parameters that are very important for succesful use of DOSGATE. DOSGATE is not very smart as far as the TNC is concerned. This is not an accident or an afterthought! Since DOSGATE performs NO TNC COMMANDS then is should be compatible with virtually ALL TNCs that have a few minor qualifications. The TNC MUST: 1 - Have its RS-232 Data Carrier Detect (DCD, pin 8) go true when a user connects, and go false when a user disconnects. This also means the your RS-232 cable must include the DCD line. Most cables designed for a modem have all the nessary lines (also important is the CTS and DSR line). 2 - Be set to go into 'TRANSPARENT' mode when the user connects, and return to 'command' mode when the user disconnects. For Kantronix TNCs: NEWMODE ON CONMODE TRANS The following settings are also desirable: AX25L2V2 ON CHECK 10 - Or some other value (not 0) PARITY 4 8BITCONV ON CMDTIME 1 COMMAND $03 FLOW OFF MRPT ON NOMODE OFF NUCR 0 NULF 0 PACTIME 10 RELINK OFF RING OFF SENDPAC $0D TRFLOW OFF TXFLOW OFF CSTAMP ON DAYTIME xxxxxxxxxxxx (set to correct time) 3 - Be set to allow only ONE user to connect at a time. USERS 1 (note: KAM & KPC4 set 'USERS 0' to be sure only one user at a time can connect) 4 - Issue a '*** CONNECTED to CALL xxx' message terminated with a Carriage Return when the user first connects. Where CALL is the id of the user who connects and xxx can be other information such as the date/time. The syntax of this message is crutial to the operation of the user id logic of DOSGATE. Every space and the case of the characters (up to the CALL) is very important. If DOSGATE does not find this message when a user logs in it will prompt the user to input his id. 5 - Be set for hardware handshaking. At this time, DOSGATE only supports hardware handshaking. This does not mean that DOS's XOFF handshaking will not work. DOSGATE hints: DOSGATE does not perform any machine protection. This means that if a remote user decides to erase a file or format your hard disk he WILL be able to do so!!! Unless you take steps to insure that he is unable to perform these dasterdly deeds! If you can trust ALL remote users, then you need not be concerned with this. Although(!), if you are allowing the general public access to your machine, then you may want to do the following: Create 'Hidden' directories which contain programs or data that you don't want the casual user to stumble across. Note: this is not a foolproof method and most 'intelligent' DOS users may be able to find the hidden directories. Set the Read Only attribute on any files that you don't want to be easily erased and don't leave any programs on the system to allow the remote user to change file attributes. Do NOT keep a copy of your format (or any similarly dangerous software) ANYWHERE on your machine. Aquire a copy of CED (or other similar DOS extention) to allow you to remove or rename internal DOS commands so that the remote user cannot DELete files, set the PATH, or look at environment variables. I use CED and map commands that I don't want the user to perform to a non existant command, this way when the user types the command DEL *.*, instead of the prompt "are you sure? ", he is greeted with the message "Invalid command or file name"! After trying a few destructive commands, the user gives up, thinking that they have all been removed! Keep only software that ok for remote users to gain access to on the machine. This way, if a user does destroy something, it will not be anything important. You also may NOT want to leave any compilers around! This will keep a *smart* user from connecting to your machine and writing a simple program while online to destroy the contents of your disks!!! Notes: MS-DOS is a trademark of Microsoft Corporation