zeek/src/file_analysis/File.h
2013-05-23 10:22:49 -05:00

274 lines
8.3 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#ifndef FILE_ANALYSIS_FILE_H
#define FILE_ANALYSIS_FILE_H
#include <string>
#include <vector>
#include "AnalyzerTags.h"
#include "Conn.h"
#include "Val.h"
#include "AnalyzerSet.h"
#include "BroString.h"
namespace file_analysis {
/**
* Wrapper class around \c fa_file record values from script layer.
*/
class File {
public:
/**
* Destructor. Nothing fancy, releases a reference to the wrapped
* \c fa_file value.
*/
~File();
/**
* @return the wrapped \c fa_file record value, #val.
*/
RecordVal* GetVal() const { return val; }
/**
* @return the value of the "source" field from #val record or an empty
* string if it's not initialized.
*/
string GetSource() const;
/**
* Set the "source" field from #val record to \a source.
* @param source the new value of the "source" field.
*/
void SetSource(const string& source);
/**
* @return value (seconds) of the "timeout_interval" field from #val record.
*/
double GetTimeoutInterval() const;
/**
* Set the "timeout_interval" field from #val record to \a interval seconds.
* @param interval the new value of the "timeout_interval" field.
*/
void SetTimeoutInterval(double interval);
/**
* @return value of the "id" field from #val record.
*/
string GetID() const { return id; }
/**
* @return value of "last_active" field in #val record;
*/
double GetLastActivityTime() const;
/**
* Refreshes "last_active" field of #val record with current network time.
*/
void UpdateLastActivityTime();
/**
* Set "total_bytes" field of #val record to \a size.
* @param size the new value of the "total_bytes" field.
*/
void SetTotalBytes(uint64 size);
/**
* Compares "seen_bytes" field to "total_bytes" field of #val record to
* determine if the full file has been seen.
* @return false if "total_bytes" hasn't been set yet or "seen_bytes" is
* less than it, else true.
*/
bool IsComplete() const;
/**
* Create a timer to be dispatched after the amount of time indicated by
* the "timeout_interval" field of the #val record in order to check if
* "last_active" field is old enough to timeout analysis of the file.
*/
void ScheduleInactivityTimer() const;
/**
* Queues attaching an analyzer. Only one analyzer per type can be attached
* at a time unless the arguments differ.
* @param args an \c AnalyzerArgs value representing a file analyzer.
* @return false if analyzer can't be instantiated, else true.
*/
bool AddAnalyzer(RecordVal* args);
/**
* Queues removal of an analyzer.
* @param args an \c AnalyzerArgs value representing a file analyzer.
* @return true if analyzer was active at time of call, else false.
*/
bool RemoveAnalyzer(const RecordVal* args);
/**
* Pass in non-sequential data and deliver to attached analyzers.
* @param data pointer to start of a chunk of file data.
* @param len number of bytes in the data chunk.
* @param offset number of bytes from start of file at which chunk occurs.
*/
void DataIn(const u_char* data, uint64 len, uint64 offset);
/**
* Pass in sequential data and deliver to attached analyzers.
* @param data pointer to start of a chunk of file data.
* @param len number of bytes in the data chunk.
*/
void DataIn(const u_char* data, uint64 len);
/**
* Inform attached analyzers about end of file being seen.
*/
void EndOfFile();
/**
* Inform attached analyzers about a gap in file stream.
* @param offset number of bytes in to file at which missing chunk starts.
* @param len length in bytes of the missing chunk of file data.
*/
void Gap(uint64 offset, uint64 len);
/**
* @param h pointer to an event handler.
* @return true if event has a handler and the file isn't ignored.
*/
bool FileEventAvailable(EventHandlerPtr h);
/**
* Raises an event related to the file's life-cycle, the only parameter
* to that event is the \c fa_file record..
* @param h pointer to an event handler.
*/
void FileEvent(EventHandlerPtr h);
/**
* Raises an event related to the file's life-cycle.
* @param h pointer to an event handler.
* @param vl list of argument values to pass to event call.
*/
void FileEvent(EventHandlerPtr h, val_list* vl);
protected:
friend class Manager;
/**
* Constructor; only file_analysis::Manager should be creating these.
* @param file_id an identifier string for the file in pretty hash form
* (similar to connection uids).
* @param conn a network connection over which the file is transferred.
* @param tag the network protocol over which the file is transferred.
* @param is_orig true if the file is being transferred from the originator
* of the connection to the responder. False indicates the other
* direction.
*/
File(const string& file_id, Connection* conn = 0,
AnalyzerTag::Tag tag = AnalyzerTag::Error, bool is_orig = false);
/**
* Updates the "conn_ids" and "conn_uids" fields in #val record with the
* \c conn_id and UID taken from \a conn.
* @param conn the connection over which a part of the file has been seen.
*/
void UpdateConnectionFields(Connection* conn);
/**
* Increment a byte count field of #val record by \a size.
* @param size number of bytes by which to increment.
* @param field_idx the index of the field in \c fa_file to increment.
*/
void IncrementByteCount(uint64 size, int field_idx);
/**
* Wrapper to RecordVal::LookupWithDefault for the field in #val at index
* \a idx which automatically unrefs the Val and returns a converted value.
* @param idx the index of a field of type "count" in \c fa_file.
* @return the value of the field, which may be it &default.
*/
uint64 LookupFieldDefaultCount(int idx) const;
/**
* Wrapper to RecordVal::LookupWithDefault for the field in #val at index
* \a idx which automatically unrefs the Val and returns a converted value.
* @param idx the index of a field of type "interval" in \c fa_file.
* @return the value of the field, which may be it &default.
*/
double LookupFieldDefaultInterval(int idx) const;
/**
* Buffers incoming data at the beginning of a file.
* @param data pointer to a data chunk to buffer.
* @param len number of bytes in the data chunk.
* @return true if buffering is still required, else false
*/
bool BufferBOF(const u_char* data, uint64 len);
/**
* Forward any beginning-of-file buffered data on to DataIn stream.
*/
void ReplayBOF();
/**
* Does mime type detection and assigns type (if available) to \c mime_type
* field in #val.
* @param data pointer to a chunk of file data.
* @param len number of bytes in the data chunk.
* @return whether mime type was available.
*/
bool DetectMIME(const u_char* data, uint64 len);
/**
* Lookup a record field index/offset by name.
* @param field_name the name of the \c fa_file record field.
* @return the field offset in #val record corresponding to \a field_name.
*/
static int Idx(const string& field_name);
/**
* Initializes static member.
*/
static void StaticInit();
private:
string id; /**< A pretty hash that likely identifies file */
RecordVal* val; /**< \c fa_file from script layer. */
bool postpone_timeout; /**< Whether postponing timeout is requested. */
bool first_chunk; /**< Track first non-linear chunk. */
bool missed_bof; /**< Flags that we missed start of file. */
bool need_reassembly; /**< Whether file stream reassembly is needed. */
bool done; /**< If this object is about to be deleted. */
AnalyzerSet analyzers; /**< A set of attached file analyzer. */
struct BOF_Buffer {
BOF_Buffer() : full(false), replayed(false), size(0) {}
~BOF_Buffer()
{ for ( size_t i = 0; i < chunks.size(); ++i ) delete chunks[i]; }
bool full;
bool replayed;
uint64 size;
BroString::CVec chunks;
} bof_buffer; /**< Beginning of file buffer. */
static int id_idx;
static int parent_id_idx;
static int source_idx;
static int is_orig_idx;
static int conns_idx;
static int last_active_idx;
static int seen_bytes_idx;
static int total_bytes_idx;
static int missing_bytes_idx;
static int overflow_bytes_idx;
static int timeout_interval_idx;
static int bof_buffer_size_idx;
static int bof_buffer_idx;
static int mime_type_idx;
};
} // namespace file_analysis
#endif