docker-openvpn/bin/start.sh

#!/bin/bash

if [ -z "$PUBLICIP" ]; then
    echo 'No PUBLICIP, exiting...'
    exit 1
fi


mkdir -p /dev/net
if [ ! -e /dev/net/tun ]; then
    mknod /dev/net/tun c 10 200
fi

if [ -z "$DNS_ONLY" ]; then
    DNS_ONLY=n
fi

if [ ! -e /etc/openvpn/server.conf ]; then
    echo "Configuration file not found. Initializing..."
    openvpn-initialize
fi

OPENVPN_CONFIG_FILE=/etc/openvpn/server.conf

if [ -z $DNS1 ]; then
    echo "DNS1 env variable not set, setting as deafault Cloudflare's 1.1.1.1"
    DNS1='1.1.1.1'
    sed -i -e 's/"dhcp-option DNS .*"/"dhcp-option DNS '${DNS1}'"/g' ${OPENVPN_CONFIG_FILE}
else

    if [[ $DNS1 =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
        echo "The DNS1 address is ${DNS1}"
        sed -i -e 's/"dhcp-option DNS .*"/"dhcp-option DNS '${DNS1}'"/g' ${OPENVPN_CONFIG_FILE}
    else
        if echo "$DNS1" | grep -qP '^[a-z0-9](?!.*--)[a-z0-9-]{1,61}[a-z0-9]$' ; then
            echo "DNS1 name of the container vaild"

            DNS1=$(host pihole | grep -oE "\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b")

            if [ ! -z "$DNS1" ]; then
                echo "The DNS1 container address is ${DNS1}"
                sed -i -e 's/"dhcp-option DNS .*"/"dhcp-option DNS '${DNS1}'"/g' ${OPENVPN_CONFIG_FILE}
            else
                echo "Impossible to resolve the DNS1 container address, exiting..."
                exit 1
            fi
        else
            echo "DNS1 name of the container not vaild, please try to not use spaces or special characters, exiting..."
            exit 1
        fi
    fi
fi

# Replace the whole line
# If DNS_ONLY is true make sure is commented, else make sure is uncommented
if [[ "$DNS_ONLY" = 'y' ]]; then
    sed -i '/push "redirect-gateway def1 bypass-dhcp"/c\#push "redirect-gateway def1 bypass-dhcp"' ${OPENVPN_CONFIG_FILE}
else
    sed -i '/push "redirect-gateway def1 bypass-dhcp"/c\push "redirect-gateway def1 bypass-dhcp"' ${OPENVPN_CONFIG_FILE}
fi


# Get the \"public\" interface from the default route
NIC=$(ip -4 route ls | grep default | grep -Po '(?<=dev )(\S+)' | head -1)
export NIC

# Add iptable rules
if [[ "$DNS_ONLY" = 'y' ]]; then
    add-openvpn-ipv4-dns-rules
else
    add-openvpn-ipv4-rules
fi

if [ "$IPV6_SUPPORT" = 'y' ]; then
    add-openvpn-ipv6-rules
fi

exec openvpn --config server.conf