[4097a] Added a new message for unconfigured classes

src/bin/dhcp4/dhcp4_messages.mes

@@ -84,6 +84,9 @@ The first argument specifies the client and transaction identification
 information. The second argument includes all classes to which the
 packet has been assigned.
 
+% DHCP4_CLASS_UNCONFIGURED %1: client packet belongs an unconfigured class: %2
+This debug message informs that incoming packet belongs to a class which cannot be found in the configuration. Either a hook written before the classification was added to Kea is used, or class naming is inconsistent.
+
 % DHCP4_CLIENTID_IGNORED_FOR_LEASES %1: not using client identifier for lease allocation for subnet %2
 This debug message is issued when the server is processing the DHCPv4 message
 for which client identifier will not be used when allocating new lease or

src/bin/dhcp4/dhcp4_srv.cc

@@ -2394,7 +2394,10 @@ Dhcpv4Srv::classSpecificProcessing(const Dhcpv4Exchange& ex) {
         const ClientClassDefPtr& ccdef = CfgMgr::instance().getCurrentCfg()->
             getClientClassDictionary()->findClass(*cclass);
         if (!ccdef) {
-            // Not found
+            // Not found: the class is not configured
+	    LOG_DEBUG(options4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_UNCONFIGURED)
+		.arg(query->getLabel())
+		.arg(*cclass);
             continue;
         }
 	// For each requested option code get the instance of the option