Add extract_metadata to main PDU classes

include/tins/eapol.h

@@ -69,6 +69,14 @@ public:
         EAPOL_WPA = 254
     };
     
+    /**
+     * \brief Extracts metadata for this protocol based on the buffer provided
+     *
+     * \param buffer Pointer to a buffer
+     * \param total_sz Size of the buffer pointed by buffer
+     */
+    static metadata extract_metadata(const uint8_t *buffer, uint32_t total_sz);
+    
     /**
      * \brief Static method to instantiate the correct EAPOL subclass 
      * based on a raw buffer.