zeek/src/file_analysis/analyzer/entropy/Entropy.h
Seth Hall b7877792c9 First commit of file entropy analyzer.
- Code comments need cleaned up still.
2013-08-05 00:02:48 -04:00

84 lines
2.2 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#ifndef FILE_ANALYSIS_ENTROPY_H
#define FILE_ANALYSIS_ENTROPY_H
#include <string>
#include "Val.h"
#include "OpaqueVal.h"
#include "File.h"
#include "Analyzer.h"
#include "events.bif.h"
namespace file_analysis {
/**
* An analyzer to produce a hash of file contents.
*/
class Entropy : public file_analysis::Analyzer {
public:
/**
* Destructor.
*/
virtual ~Entropy();
/**
* Create a new instance of an Extract analyzer.
* @param args the \c AnalyzerArgs value which represents the analyzer.
* @param file the file to which the analyzer will be attached.
* @return the new Extract analyzer instance or a null pointer if the
* the "extraction_file" field of \a args wasn't set.
*/
static file_analysis::Analyzer* Instantiate(RecordVal* args, File* file);
/**
* Incrementally hash next chunk of file contents.
* @param data pointer to start of a chunk of a file data.
* @param len number of bytes in the data chunk.
* @return false if the digest is in an invalid state, else true.
*/
virtual bool DeliverStream(const u_char* data, uint64 len);
/**
* Finalizes the hash and raises a "file_entropy_test" event.
* @return always false so analyze will be deteched from file.
*/
virtual bool EndOfFile();
/**
* Missing data can't be handled, so just indicate the this analyzer should
* be removed from receiving further data. The hash will not be finalized.
* @param offset byte offset in file at which missing chunk starts.
* @param len number of missing bytes.
* @return always false so analyzer will detach from file.
*/
virtual bool Undelivered(uint64 offset, uint64 len);
protected:
/**
* Constructor.
* @param args the \c AnalyzerArgs value which represents the analyzer.
* @param file the file to which the analyzer will be attached.
* @param hv specific hash calculator object.
* @param kind human readable name of the hash algorithm to use.
*/
Entropy(RecordVal* args, File* file);
/**
* If some file contents have been seen, finalizes the hash of them and
* raises the "file_hash" event with the results.
*/
void Finalize();
private:
EntropyVal* entropy;
bool fed;
};
} // namespace file_analysis
#endif