First version of the status engine implementation

The Status Engine allow the measurements of how many ModSecurity
instances are running around the world, as long as information
on how many times it had been restarted and so on. Everytime that
the server is started it perform a DNS query that is redirected
to our servers, that query constains information about the
ModSecurity version and it dependencies versions. It also sends a
unique indetification generate locally for the server, avoiding
counting the same server twice while generating the statistics.
This id is a sha-1 hash of the machine name + mac address of the
first network adapter. In this commit it is enabled by default,
in the release will be a configuration option to disable this
functionality. It also important to cite that the information
gather by this query will be also available in ModSecurity website
public open via a JSON stateless API. There will be an fancy
heatmap as well.

apache2/msc_status_engine.h

@@ -0,0 +1,32 @@
+/*
+* ModSecurity for Apache 2.x, http://www.modsecurity.org/
+* Copyright (c) 2004-2013 Trustwave Holdings, Inc. (http://www.trustwave.com/)
+*
+* You may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* If any of the files related to licensing are missing or if you have any
+* other questions related to licensing please contact Trustwave Holdings, Inc.
+* directly using the email address security@modsecurity.org.
+*/
+
+#ifndef MSC_STATUS_ENGINE_H
+#define MSC_STATUS_ENGINE_H
+
+#include "apr.h"
+#include "apr_pools.h"
+#include "apr_version.h"
+#include "apr_optional.h"
+#include "msc_pcre.h"
+
+#define STATUS_ENGINE_DNS_IN_BETWEEN_DOTS 13
+
+#define STATUS_ENGINE_DNS_SUFFIX "status.modsecurity.org"
+
+static const char msc_status_engine_basis_32[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+
+int msc_status_engine_call(void);
+
+#endif