DNET V1.20 DNET (c)Copyright 1987 Matthew Dillon, All Rights Reserved Matthew Dillon 891 Regal Rd Berkeley, Ca. 94708 ...!ihnp4!ucbvax!dillon USENET dillon@ucbvax.Berkeley.edu ARPANET forum: ...!ihnp4!ucbvax!cory!dnet dnet%cory@ucbvax.berkeley.edu COMPILING, UNIX: Simply run the shell script MAKE. COMPILING, AMIGA: No compilation is needed, binaries are in the dnet.amiga/bin . To compile, you must have AZTEC C. You MUST make a precompiled symbol table file which contains all the subdirectory includes (see SYMBOLS.C in the INCLUDE directory). You need to assign comp: somewhere, make a directory 'include', and place the symbol table in that. As you will note looking at SYMBOLS.C, the precompiled symbol table MUST be made with the +L option. GETTING IT RUNNING: Setting it up on the UNIX system: (1) Make a directory (for example, ~/.DNET) (2) Modify your .cshrc , adding the following line: setenv DNETDIR ~/.DNET/ (the hanging slash is essential) (3) All binaries are usually kept in dnet.unix/bin, add this directory to your path (in your .cshrc) (4) Place the file 'dnet.servers' in ~/.DNET . Modify the file according to your home directory and where you have put the servers. The file currently cannot handle ~ ... a FULL PATH IS REQUIRED. NOTE: You may want to chmod the directory 700 to disallow any unauthorized access to the network. Setting it up on the Amiga: (1) Set the proper baud rate in preferences. Bits and protocol do not have to be setup. Alternately, you can specify the baud rate on the command line (-bBAUD) when you run DNET. (2) DNET and the client programs must be available by your path. The servers (scopy sterm scli) may be placed anywhere. (3) The file dnet.servers must be placed in S:, and modified according to where you put the servers. DNET uses this file to auto-start servers. NOTE: The 'directory' field, currently holding 'ram:', is also currently not implemented. You should use the -d option with the UNIX end putfiles (see below) Starting it up: From your Amiga, RUN DNET. A terminal window will appear. Dialup and login to your UNIX account. Use an Amiga termcap ('sun' and 'ansi' also work). From your UNIX prompt type 'dnet', thereby starting DNET on the UNIX end. The DNET on the Amiga end should detect this, close the DNET terminal window, and automatically startup an FTERM. DNET is now running. You may then experiment around with multiple FTERM's, PUTFILES, etc... (see below for command format). NOTE: The Menu options in the original DNET window are used (1) to restart DNET if the remote end is already running, (2) to send a BREAK over the serial line (3) to exit DNET (same as the close gadget). KILLING DNET: If you currently have a good connection, you should be able to close all currently active client programs. It will now appear that everything is closed down. However, DNET is still running in the background (and you can even startup various client programs again). 1> quitdnet This will send a packet to DNET causing the remote end (the UNIX end) to quit. Wait two or three seconds, then 1> BREAK 2 Where '2' is the CLI you ran DNET under originally. It may not be a '2'. This should cause DNET's window to come up again, and since the DNET on the UNIX end has exited, you should have a UNIX prompt again. NOTE: If you have not closed all clients, they will exit at this point (though not as nicely). Always wait for all clients to exit before closing DNET. At this point you may close the DNET window to kill dnet. ------------ Alternately, you may simply hangup the modem, BREAK dnet, and close the DNET-Terminal window. Be sure to close all active clients before doing so. The only processes that will be left running on the UNIX system will be any servers that were started up. These take 0 cpu and very little swap. SERVERS Servers are started on demand on both ends. The Amiga end will kill any servers that were started when you close DNET. The UNIX end will leave any servers idle in the background when you kill DNET or hangup. These servers will be available the next time you log in. To kill servers on the UNIX end, you must kill the process id. 'ps x' will give you all processes running under your uid. A simple 'kill pid' should do it. BASIC THEORY, UNIX END: The DNET driver accepts connections from clients over UNIX domain sockets. It multiplexes and packetizes the data, sends it to whatever is on descriptor 0 (usually your tty). It receives data from the serial port, de-packetizes it, demuxes it, and sends it to the proper client. Additionaly, it receives open requests from the remote end and tries to connect to the proper server, starting the server if necessary. All the servers are UNIX domain sockets placed in the directory specified by the enviroment variable DNETDIR (if the enviroment variable DNETDIR is not defined, then in whatever directory they were run from). The path specification in this enviroment variable must have a hanging slash. BASIC THEORY, AMIGA END: The communications protocol, obviously, is the same. In fact, it is completely symetrical (there is no master/slave relationship in this protocol). The DNET driver on the Amiga usually opens the serial port with the default preferences (or current modes if you have a terminal program active at the time you run DNET). public message ports are used to send messages back and forth. The DNET driver on the Amiga end will allocate memory as needed to hold incomming data. FLOW CONTROL IS NOT IMPLEMENTED. CLIENT PROGRAMS AND ASSOCIATED SERVERS: SERVERS CLIENT PROGRAMS PORT UNIX AMIGA UNIX AMIGA ---- --------------- -------------------------- 8192 SCOPY SCOPY PUTFILES PUTFILES 8193 SSHELL - - FTERM 8193 8194 - - - - 8195 (1) STERM DRAW 8195 FTERM 8196 - SCLI DSOC 8196 - 8197 SLOADAV - - LOADAV (1) This servers is implemented internally. AMIGA SERVERS: STERM -'talk' window. Brings up a talk window. You can talk with whoever is on the other end (an FTERM if the other end is another Amiga, or a DRAW 8195 if the other end is a UNIX machine). SCLI -remote shell unix->amiga. NOTE1: My PIPE: device must exist for this to work. NOTE2: Only works properly if you are at a CLI prompt when you exit (^C). NOTE3: Currently a hack. Currently can handle only one connection at a time. SCOPY -File copy server. Receives files and directory structures from the remote client and places them in the specified directory. If no directory specified by the remote client, they are placed in DF0: . Currently can handle only one connection at a time. UNIX SERVERS: SCOPY -same as Amiga server, but for Amiga->UNIX transfers. However, the UNIX version can handle multiple connections (multiple putfiles from the Amiga end). SSHELL -shell server, for use with the FTERM program on the Amiga end (when qualified by port 8193). This is the same as FTERM's default port, but automatically exec'd an 'rlogin localhost' in the terminal window yielding a named shell. SLOADAV -Load average server, for use the LOADAV on the Amiga end. The program 'la' must exist on the UNIX end. CLIENT PROGRAMS: (unix) DRAW port# Put terminal in RAW mode and connect to the specified port. The remote end must recognize some way of sending an EOF (STERM recognizes a ^C, for instance) because only the remote end can close the connection. (unix) DSOC port# Leave terminal in cooked mode and connect to the specified port #. This has the advantage that ^C's will kill the DSOC. Additionaly, you have input-editing. Used mainly with remote shells. (unix/amiga) PUTFILES [-ddirectory] file/dir file/dir file/dir .... Send one or more files or directories to the remote host, placing them in the directory specified by the -d command. If no -d is specified, DF0: is used (amiga server). The UNIX server uses the directory specified in dnet.servers on the UNIX end as a default. Currently, no file compression is done. (amiga) TERM [port#] OBSOLETE (amiga) FTERM [port#] Used to connect to a pty/shell on the UNIX end. This is faster than TERM (one less process to go through). (amiga) LOADAV [seconds/sample] Connect to the remote SLOADAV server on the UNIX system, and display the load graphically. Updates occur every 60 seconds, or in the time specified by the argument. (amiga) QUITDNET First close any active clients (terminal windows, loadav windows, etc....). Ensure the remote end is not connected to any local servers. Cause the DNET on the UNIX end to quit. You then BREAK the DNET on the Amiga end, getting a terminal window. You can then close the window and thus quit out of DNET on the local end. QUICKIE DESCRIPTION OF LOW LEVEL PACKET THEORY: DNET uses a windowed-packet scheme, as in transmission windows... up to 4 packets can be sent before one of them is acked. Each packet is fully checked with three check bytes (one for the header, and two for the data). If a packet fails it is ignored. If the receiver detects a missing packet it requests it be resent. If the sender doesn't get an ack within a given timeout it sends a CHECK packet, which asks the receiver if it got it or not (rather than just resend the packet, which might take a while). Taking the possibilities of long freeze times on the UNIX end due to high load factor, the UNIX DNET will play catch up if it receives multiple CHECK packets for the same window, responding only to the last one received. The channel multiplexing is embedded in the packet data... that is, you might have the data for several channels in a single packet, so maximum throughput is maintained even when you have a lot of little things going on. The packet protocol can handle up to 65535 channels. The actual implementation can only handle 128 handles, and is further limited by the number of file descriptors available on the UNIX side. This is usually around 64, or approximately 60 connections. -Matt