container-openvpn/bin/ovpn_init

#!/bin/bash

#
# Initialize the PKI and OpenVPN configs
#

set -ex

server_url=$1

# Server name is in the form "udp://vpn.example.com:1194"
if [[ "$server_url" =~ ^((udp|tcp)://)?([0-9a-zA-Z\.]+)(:([0-9]+))?$ ]]; then
    proto=${BASH_REMATCH[2]};
    cn=${BASH_REMATCH[3]};
    port=${BASH_REMATCH[5]};
else
    echo "Common name not specified"
    exit 1
fi

# Apply defaults
[ -z "$proto" ] && proto=1194
[ -z "$port" ] && port=udp

# Specify "nopass" as arg[2] to make the CA insecure
nopass=$2

# Provides a sufficient warning before erasing pre-existing files
easyrsa init-pki

# CA always has a password for protection in event server is compromised. The
# password is only needed to sign client/server certificates.  No password is
# needed for normal OpenVPN operation.
easyrsa build-ca $nopass

easyrsa gen-dh
openvpn --genkey --secret $OPENVPN/pki/ta.key

# Was nice to autoset, but probably a bad idea in practice, users should
# have to explicitly specify the common name of their server
#if [ -z "$cn"]; then
#    #TODO: Handle IPv6 (when I get a VPS with IPv6)...
#    ip4=$(dig +short myip.opendns.com @resolver1.opendns.com)
#    ptr=$(dig +short -x $ip4 | sed -e 's:\.$::')
#
#    [ -n "$ptr" ] && cn=$ptr || cn=$ip4
#fi

echo "$server_url" > $OPENVPN/server_url

# For a server key with a password, manually init; this is autopilot
easyrsa build-server-full $cn nopass

ovpn_genconfig "$cn"