elks-enhanced

# ELKS Enhanced

ELKS Enhanced is a maintained ELKS fork for Intel IA16 systems: 8086, 8088,
80186, 80188, 80286, NEC V20/V30 and close compatibles. It targets real XT/AT
class hardware, SBCs and FPGA systems, and emulator setups such as QEMU.

This tree keeps the ELKS kernel, driver model, filesystems and userspace
environment, but replaces the historical userspace networking stack with Adam
Dunkels' uIP. The goal is to keep the ELKS hardware and kernel boundaries
stable while moving protocol handling onto a smaller, better understood TCP/IP
engine that fits 16-bit systems well.

## Platform

- 16-bit x86 and IA16-compatible systems
- ELKS kernels and userspace images
- Real ISA hardware and QEMU test targets

## Networking Direction

The major change in this fork is the networking stack replacement:

- the old `ktcp` userspace stack is removed
- `/bin/uip` is the active network daemon
- ELKS keeps its kernel-side socket layer and hardware drivers
- the userspace bridge is unified as `/dev/netdev`
- TCP and UDP both run through the uIP-backed bridge
- uIP DHCP client and resolver support are available through build options

The integration was done to keep changes minimal on both sides:

- ELKS keeps its NIC drivers, kernel socket code and application model
- uIP stays close to its original structure and naming where possible
- the bridge layer is where ELKS and uIP are adapted to each other

## Why Replace The Old Stack

- uIP is much smaller and simpler than the old ELKS-specific networking stack
- the code path is easier to reason about on 8086-class memory budgets
- upstream uIP already provides TCP, UDP, DHCP and resolver building blocks
- serial links and ethernet links can be smoke-tested in QEMU with one daemon
- less ELKS-only network protocol code has to be maintained going forward

In practice, this gives ELKS a cleaner split between hardware access,
kernel/userspace socket ABI, and the protocol implementation itself.

## External Repositories

This repository no longer vendors the ELKS BearSSL or Dropbear ports.
They live in separate repositories and are fetched into `extapps/` when needed:

- `ssh-daemon-project` for the Dropbear ELKS port
- `bearssl` for the BearSSL ELKS port

Use `./buildext.sh dropbear bearssl` to fetch and build them locally.
The `menuconfig` entries for these extapps remain in ELKS so images can still
include them, but their source now lives outside this tree.

## Building

Base ELKS build instructions remain in [BUILD.md](BUILD.md).

Typical workflow:

```sh
. ./env.sh
make menuconfig
make -j1 all
./buildext.sh dropbear bearssl
```

For extapp smoke tests, the fetched trees must exist under `extapps/`.
The helper scripts will tell you which `buildext.sh` target to run if an
external tree is missing.

## Current Networking Scope

The uIP-backed networking work in this fork includes:

- ethernet via existing ELKS NIC drivers
- SLIP and CSLIP serial networking
- unified TCP and UDP userspace bridge
- DHCP client support
- resolver integration for ELKS networking tools
- QEMU smoke coverage for ethernet, SLIP and CSLIP paths

## Upstream ELKS

This fork starts from upstream ELKS and remains compatible with the general
ELKS build and image model. For the broader project history and upstream
documentation, see the ELKS documentation tree in `Documentation/`.