Using cross is probably a simpler solution, but booting up a 2GiB container for each compilation takes too long, so I decided to use a FreeBSD VM.

This is NOT a step-by-step tutorial but a collection of steps that I remember doing to get this to work.

• The following directories and files are synced to the FreeBSD VM using rsync
  • /Cargo.toml
  • /Cargo.lock
  • /src/*
• build_and_run.sh is executed on the FreeBSD VM in the project directory
  • Build the project in release mode for x86_64-unknown-freebsd
  • Send SIGTERM to all running openvpn-monitor processes using killall
  • Wait until all openvpn-monitor processes have exited
  • Copy the compiled binary to /usr/local/bin
  • Run the binary in the background

• Download a FreeBSD image
• Add the following to /etc/ssh/sshd_config
  • PermitRootLogin yes
  • AuthorizedKeysFile /root/.ssh/authorized_keys
• Add your SSH key from Windows to /root/.ssh/authorized_keys
• Install Rust on the FreeBSD VM
• Generate an SSH key using ssh-keygen -t ed25519
• Install rsync using pkg install rsync
• Install bash using pkg install bash

• Add the SSH key from the FreeBSD VM to the admin user
  • System -> User Manager -> Users -> admin -> Authorized SSH Keys

• Install a Debian WSL2 instance
  • linuxfordevices.com/tutorials/linux/install-debian-on-windows-wsl
• Create a symlink for convenience
  • ln -s /mnt/c/path/to/openvpn-monitor/ openvpn-monitor
• Run sync.sh to compile on the FreeBSD VM and deploy to pfSense