![fwlnx](https://gitlab.com/fwlnx/fwlnx/-/raw/master/fwlnx.png)

# fwlnx

Firewall Linux - A small and simple Busybox/Linux Firewall Distribution

It combines an optimized Linux Kernel, Busybox and a simple Webinterface and API to configure. It is not meant to be a replacement to far superiour Appliances but as an alternative solution for typical home use.

## Target platforms

- QEMU/KVM
- [PCEngines APU2](https://www.pcengines.ch/apu2.htm)

## Planned initial features

- Firewall
  - [ ] NAT
  - [ ] Rules
  - [ ] UPnP
- [ ] DynDNS
- VPN
  - [ ] OpenVPN
  - [ ] Wireguard
- [ ] NTP
- [ ] DHCP
- [ ] DNS
- [ ] Auto config backup
- [ ] Cron/Timers

## Design

### Partitioning

MBR/BIOS:

```
/dev/disk:
  /dev/disk1  ext4                   /boot
  /dev/disk2  swap                   [SWAP]
  /dev/disk3  btrfs@home             /home
  /dev/disk3  btrfs@root-2021-04-01  /
  /dev/disk3  btrfs@root-2021-04-20  /
  /dev/disk3  btrfs@conf-2021-04-01  /config
  /dev/disk3  btrfs@conf-2021-04-20  /config
```

- Every installed release has it's own subvolume for rootfs and config in case a configuration changes with an update
- The user can choose which one to boot into

### Update flow

State before the update:

- boot entry `last` is set to version 1 (last known working version)
- boot entry `current` is also set to version 1
- on every boot the default boot entry is set to `last` automatically in early boot

Update process:

- a new version is downloaded as a btrfs snapshot and put into place as version 2
- `current` boot entry is modified to boot the new version
- `current` is set as default boot entry

- device reboots into new version 2 via `current` boot entry
- early boot sets `last` as default boot entry
- after successful boot:
  - the user marks the system as functional which sets the `last` boot entry to the current version
- if something goes wrong:
  - the system reboots, now with the `last` entry being the default booting into the last known working system
  - the user gets displayed an error because `last` and `current` is not the pointing to the same version and `last` is booted indicating an error

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Icon partly from [stockio](https://www.stockio.com/free-icon/nature-icons-penguin)