README

PKTNDIS

An NDIS 2.0 MAC driver for DOS that bridges a Packet Driver interface to NDIS. This allows NDIS-based protocol stacks (such as Microsoft LAN Manager, Windows for Workgroups, or MS TCP/IP) to operate over emulators and environments that only provide a Packet Driver interface — most notably dosemu2.

This is a retro-computing project. The code is written and built entirely in DOS using period-correct tools — Borland Pascal 7, Borland MAKE, and a real-mode debugger. The only concession to modernity is a comfortable editor.

Download

Pre-built binaries are available on the Releases page. No build tools are required to use them.

Installation

Copy pktndis.dos and oemsetup.inf from the release archive to a directory accessible from DOS. In the LAN Manager or WfW Setup program, select "Unlisted or Updated Network Adapter" and point it to that directory.

PROTOCOL.INI Parameters

; section name may differ in your installation
[pktndis]
DriverName=PKTNDIS$     ; mandatory, must be PKTNDIS$
interrupt=0             ; auto-detect Packet Driver interrupt (default)
interrupt=0x61          ; use a specific interrupt number
hide=1                  ; hide the Packet Driver interface (default)
hide=0                  ; don't hide the Packet Driver interface

The hide option makes the underlying Packet Driver invisible, forcing dual-stack software to use the NDIS interface.

Building from Source

Source code is provided for reference. The release binaries are built from a larger codebase that provides an optimized runtime, a more efficient buffer allocator, and a smaller memory footprint. That codebase cannot be open-sourced due to Borland's RTL license terms, so official binaries are available on the Releases page.

Requirements

• Borland Pascal 7.01 (untested with earlier versions)

Build

Edit src/makefile and set BPROOT to your Borland Pascal installation directory. Then:

cd src
make

The output (pktndis.exe) is placed in src/build/. Rename it to pktndis.dos for use as an NDIS driver.

Distribution build

cd src
make dist

Performs a build and places the driver and all necessary files, like end-user documentation, in src/dist.

Project Structure

src/
  pktndis.pas   Main program and DOS driver entry point
  driver.pas    NDIS MAC driver implementation
  ndis.pas      NDIS 2.0 interface (Pascal translation of IBM DDK headers)
  pktdrv.pas    Packet Driver interface
  tinyheap.pas  Fixed-size pool allocator for network buffers
  tinyque.pas   Static queue for interrupt-context packet handling
  utils.pas     Minimal console/debug I/O routines
  bits.pas      Low-level types and memory primitives
  doslib.pas    DOS system call interface
  makefile      Borland MAKE makefile
  bpc.cfg       Compiler configuration
etc/
  oemsetup.inf  NDIS driver installation file
bin/
  xdate.exe     Build tool: timestamp generator (DOS binary)

How It Works

PKTNDIS locates an existing Packet Driver on a software interrupt, registers itself as an NDIS MAC driver, and translates between the two interfaces:

• Receive path, sync: Packet Driver receive upcalls are queued and delivered to NDIS protocol drivers via ReceiveLookahead and TransferData.
• Receive path, async: Packet Driver receive upcalls are delivered via ReceiveChain.
• Transmit path: NDIS TransmitChain calls are forwarded to the Packet Driver's SendPkt.

The driver operates entirely in real mode. The release binaries require a 386 or above. The reference source can be built for 8086.

See Also

DIS_PKT — the reverse: an NDIS to Packet Driver shim for DOS.

License

MIT