ovpn: Convert from servername -> server_url

* Previously the server name cached the common name generated during
  init and assumed always 1194/udp.
* The new configuration allows for users to pass in a url in a new form
  that allows the protocol to be specified as well as the port.
* Example: udp://vpn.example.com:1194
* Try to be backwards compatible.

bin/ovpn_getclient

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 #
 # Get an OpenVPN client configuration file
@@ -6,19 +6,30 @@
 
 set -ex
 
-cn=$1
+if [ -s "$OPENVPN/server_url" ]; then
+    server_url=$(cat "$OPENVPN/server_url" 2> /dev/null)
+else
+    # TODO Backwards compatible, need to throw away eventually
+    server_url=$(cat "$OPENVPN/servername" 2> /dev/null)
+fi
 
-if [ -z "$cn" ]; then
+if [[ "$server_url" =~ ^((udp|tcp)://)?([0-9a-zA-Z\.]+)(:([0-9]+))?$ ]]; then
+    proto=${BASH_REMATCH[2]};
+    servername=${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
+
 if [ ! -f "$EASYRSA_PKI/private/$cn.key" ]; then
     easyrsa build-server-full $cn nopass
 fi
 
-servername=$(cat $OPENVPN/servername)
-
 cat <<EOF
 client
 nobind
@@ -44,6 +55,6 @@ $(cat $EASYRSA_PKI/ta.key)
 key-direction 1
 
 <connection>
-remote $servername 1194 udp
+remote $servername $port $proto
 </connection>
 EOF