openvpn.sh: Split in to smaller scripts

* Split soon to be massive wrapper into smaller managable scripts.
* Re-organized Dockerfile to exploit cache when rebuilding

bin/ovpn_init

@@ -0,0 +1,57 @@
+#!/bin/sh
+
+#
+# Initialize the PKI and OpenVPN configs
+#
+
+set -ex
+
+cn=$1
+
+if [ -z "$cn" ]; then
+    echo "Common name not specified"
+    exit 1
+fi
+
+# Provides a sufficient warning before erasing pre-existing files
+easyrsa init-pki
+
+# For a CA key with a password, manually init; this is autopilot
+easyrsa build-ca nopass
+
+easyrsa gen-dh
+openvpn --genkey --secret $OPENVPN/pki/ta.key
+
+if [ -z "$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=$ip4
+fi
+
+echo "$cn" > $OPENVPN/servername
+
+easyrsa build-server-full $cn nopass
+
+[ -f "$OPENVPN/udp1194.conf" ] || cat > "$OPENVPN/udp1194.conf" <<EOF
+server 192.168.255.128 255.255.255.128
+verb 3
+#duplicate-cn
+key $EASYRSA_PKI/private/$cn.key
+ca $EASYRSA_PKI/ca.crt
+cert $EASYRSA_PKI/issued/$cn.crt
+dh $EASYRSA_PKI/dh.pem
+#tls-auth $EASYRSA_PKI/ta.key
+#key-direction 0
+keepalive 10 60
+persist-key
+persist-tun
+push "dhcp-option DNS 8.8.4.4"
+push "dhcp-option DNS 8.8.8.8"
+
+proto udp
+port 1194
+dev tun1194
+status /tmp/openvpn-status-1194.log
+EOF