TinyTcp Public Domain Release

The files in this release contain a simple implementation of TCP & FTP, suitable for burning into ROM. It is, in effect, a big hack put together in two or three days. It works for us, though, and you might like it, too. We use it to boot our image processor by retrieving a load file using the standard FTP server.

The code is intended to use the buffers from the Ethernet interface, although shadow buffers could be hidden in the driver with no problem. On one home-brew board here and didn't support byte-mode access to it. Hence, the code takes pains to fool our local compiler into never generating byte- or bit-mode instructions.

Since we have already burned the TCP into ROM, it is unlikely that any further development will take place at IMAGEN. I would be willing to act as a clearinghouse for future improvements to the code.

Warning: the code was intended for a 68000, and doesn't have any byte swapping support in it. Shouldn't be too hard to add if you want to run it on a little-endian machine.

Please note (and honor) the copyright on each file:

Copyright (C) 1986, IMAGEN Corporation "This code may be duplicated in whole or in part provided that [1] there is no commercial gain involved in the duplication, and [2] that this copyright notice is preserved on all copies. Any other duplication requires written notice of the author (Geoffrey H. Cooper)."

...in other words, do what you want with the code, but don't sell it and give IMAGEN and me credit on whatever you produce. If you develop a product based on this code and want to sell it, give me a call and I'll be reasonable.

This code is distributed "as is." Neither the author nor IMAGEN Corporation guarantees that it works or meets any particular specifications. The act of distributing this software does not represent a commitment by either the author nor IMAGEN Corporation to provide maintenance or consulting services related to this software.

But feel free to ask me any questions that you can't answer for yourself.

- Geof Cooper
  Imagen Corporation
  (408)986 9400
  [imagen!geof@decwrl.dec.com, {decwrl,saber}!imagen!geof]
  April 16, 1986

The package requires some system support:

clock_ValueRough() - should be a procedure that returns the current
    value of a millisecond clock.  The procedure is called frequently,
    so that interrupts are not needed to service the clock.  Our
    implementation polls the real time timer and assumes that it is
    called frequently enough so that it doesn't miss clock ticks (Since
    the timer is only used for network timeouts, it doesn't really matter
    if it does miss clock ticks, of course).  Systems without a clock
    could probably get by with a procedure that increments a static
    variable and returns it, by adjusting the timeout constants in the
    program.

Network driver - some network interface  driver is needed.  A driver for a
    3Com multibus (ethernet) board is included; this board isn't made
    anymore (at least not by 3Com, there are still compatible boards
    being made, but I don't know of any being popularly distributed),
    so you'll probably need to write a driver for the board in your system.

Guide to source files:

sed.c - Simple Ethernet Driver - Driver for 3Com multibus card.  If you
        have another type of Ethernet board, you can use this driver as
        a template.

sed.h - header file for the above.

arp.c - Implementation of Address Resolution Protocol.  Note that there
        is no arp "mapping" per se.  The higher level code (tcp, in this
        case) is required to keep track of internet and ethernet addresses.

tinytcp.c - Implementation of TCP.

tinytcp.h - Header file for above, and for everything else.

tinyftp.c - Implementation of FTP, only allows files to be retrieved,
            not sent.