Initial support to load rules from a remote server

New directive `SecRemoteRules' was added. It allows the user to load a
set of rules from a given HTTP server.

apache2/msc_remote_rules.h

@@ -0,0 +1,67 @@
+/*
+* 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_REMOTE_RULES_H
+#define MSC_REMOTE_RULES_H
+
+#include <apr_general.h>
+#include <apr_optional.h>
+#include <apr_thread_pool.h>
+#include <curl/curl.h>
+
+#include <apr_sha1.h>
+#include <apr_crypto.h>
+#include "http_core.h"
+
+typedef struct msc_remote_rules_server msc_remote_rules_server;
+struct msc_curl_memory_buffer_t;
+
+#include "modsecurity.h"
+
+struct msc_remote_rules_server {
+        directory_config *context;
+        const char *context_label;
+        const char *uri;
+        const char *key;
+        int amount_of_rules;
+};
+
+const char *msc_remote_invoke_cmd(const command_rec *cmd, cmd_parms *parms,
+                              void *mconfig, const char *args);
+
+int msc_remote_grab_content(apr_pool_t *mp, const char *uri, const char *key,
+    struct msc_curl_memory_buffer_t *chunk, char **error_msg);
+
+int msc_remote_enc_key_setup(apr_pool_t *pool,
+        const char *key,
+        apr_crypto_key_t **apr_key,
+        apr_crypto_t *f,
+        unsigned char *salt,
+        char **error_msg);
+
+int msc_remote_decrypt(apr_pool_t *pool,
+        const char *key,
+        struct msc_curl_memory_buffer_t *chunk,
+        unsigned char **plain_text,
+        apr_size_t *plain_text_len,
+        char **error_msg);
+
+int msc_remote_add_rules_from_uri(cmd_parms *orig_parms,
+        msc_remote_rules_server *remote_rules_server,
+        char **error_msg);
+
+int msc_remote_clean_chunk(struct msc_curl_memory_buffer_t *chunk);
+
+#endif
+