openvpn_otp.sh

#!/bin/bash

# Import your .ovpn file using Network Manager
# Mark the option:"Use this connection only for resources on its network" both on IPv4 and IPv6 tabs
# Set the next 3 variables
# Run the script to connect, you may disconnect using Network Manager's UI

VPNUSER="user.name"
VPNPASS="yourshamefulpassword"
VPNTOTP="base32token"

if ! command -v oathtool &> /dev/null; then
    echo "Error: oathtool is not installed. Install it using: sudo apt install oathtool"
    exit 1
fi

TOTP_CODE=$(oathtool --totp --base32 "$VPNTOTP")
FINAL_PASSWORD="${VPNPASS}${TOTP_CODE}"

CONN=$(nmcli connection show | grep $VPNUSER | awk '{print $1}')
if [ -z "$CONN" ]; then
    echo "Connection with '$VPNUSER' in the name not configured"
    exit 1
fi

nmcli connection down "$CONN"
nmcli connection modify "$CONN" vpn.user-name "$VPNUSER"
nmcli connection up "$CONN" --ask <<< "$FINAL_PASSWORD"