libraries/pcappp/include/pcapplusplus/TLVData.h

399 lines
13 KiB
C++

#ifndef PACKETPP_TLV_DATA
#define PACKETPP_TLV_DATA
#include "Layer.h"
#include "IpAddress.h"
#include <string.h>
/// @file
/**
* \namespace pcpp
* \brief The main namespace for the PcapPlusPlus lib
*/
namespace pcpp
{
/**
* @class TLVRecord
* A wrapper class for a Type-Length-Value (TLV) record. This class does not create or modify TLV records, but rather
* serves as a wrapper and provides useful methods for retrieving data from them. This class has several abstract methods
* that should be implemented in derived classes. These methods are for record length value calculation (the 'L' in TLV)
* which is implemented differently in different protocols
*/
template<typename TRecType, typename TRecLen>
class TLVRecord
{
protected:
/** A struct representing the TLV construct */
struct TLVRawData
{
/** Record type */
TRecType recordType;
/** Record length in bytes */
TRecLen recordLen;
/** Record value (variable size) */
uint8_t recordValue[];
};
TLVRawData* m_Data;
public:
/**
* A c'tor for this class that gets a pointer to the TLV record raw data (byte array)
* @param[in] recordRawData A pointer to the TLV record raw data
*/
TLVRecord(uint8_t* recordRawData)
{
assign(recordRawData);
}
/**
* A copy c'tor for this class. This copy c'tor doesn't copy the TLV data, but only the pointer to it,
* which means that after calling it both the old and the new instance will point to the same TLV raw data
* @param[in] other The TLVRecord instance to copy from
*/
TLVRecord(const TLVRecord& other)
{
m_Data = other.m_Data;
}
/**
* A d'tor for this class, currently does nothing
*/
virtual ~TLVRecord() { }
/**
* Assign a pointer to the TLV record raw data (byte array)
* @param[in] recordRawData A pointer to the TLV record raw data
*/
void assign(uint8_t* recordRawData)
{
if(recordRawData == NULL)
m_Data = NULL;
else
m_Data = (TLVRawData*)recordRawData;
}
/**
* Overload of the assignment operator. This operator doesn't copy the TLV data, but rather copies the pointer to it,
* which means that after calling it both the old and the new instance will point to the same TLV raw data
* @param[in] other The TLVRecord instance to assign
*/
TLVRecord& operator=(const TLVRecord& other)
{
m_Data = other.m_Data;
return *this;
}
/**
* Overload of the equality operator. Two record are equal if both of them point to the same data, or if they point
* to different data but their total size is equal and the raw data they both contain is similar.
* @param[in] rhs The object to compare to
* @return True if both objects are equal, false otherwise
*/
bool operator==(const TLVRecord& rhs) const
{
if (m_Data == rhs.m_Data)
return true;
if (getTotalSize() != rhs.getTotalSize())
return false;
if (isNull() || ((TLVRecord&)rhs).isNull())
return false;
return (memcmp(m_Data, rhs.m_Data, getTotalSize()) == 0);
}
/**
* Overload of the not equal operator.
* @param[in] rhs The object to compare to
* @return True if objects are not equal, false otherwise
*/
bool operator!=(const TLVRecord& rhs) const
{
return !operator==(rhs);
}
/**
* @return The type field of the record (the 'T' in __Type__-Length-Value)
*/
TRecType getType() const { return m_Data->recordType; }
/**
* @return A pointer to the value of the record as byte array (the 'V' in Type-Length- __Value__)
*/
uint8_t* getValue() const { return m_Data->recordValue; }
/**
* @return True if the TLV record raw data is NULL, false otherwise
*/
bool isNull() const { return (m_Data == NULL); }
/**
* @return True if the TLV record raw data is not NULL, false otherwise
*/
bool isNotNull() const { return (m_Data != NULL); }
/**
* @return A pointer to the TLV record raw data byte stream
*/
uint8_t* getRecordBasePtr() const { return (uint8_t*)m_Data; }
/**
* Free the memory of the TLV record raw data
*/
void purgeRecordData() { if (!isNull()) delete [] m_Data; }
/**
* A templated method to retrieve the record data as a certain type T. For example, if record data is 4B long
* (integer) then this method should be used as getValueAs<int>() and it will return the record data as an integer.<BR>
* Notice this return value is a copy of the data, not a pointer to the actual data
* @param[in] offset The offset in the record data to start reading the value from. Useful for cases when you want
* to read some of the data that doesn't start at offset 0. This is an optional parameter and the default value
* is 0, meaning start reading the value at the beginning of the record data
* @return The record data as type T
*/
template<typename T>
T getValueAs(size_t offset = 0) const
{
if (getDataSize() - offset < sizeof(T))
return 0;
T result;
memcpy(&result, m_Data->recordValue + offset, sizeof(T));
return result;
}
/**
* A templated method to copy data of type T into the TLV record data. For example: if record data is 4[Bytes] long use
* this method with \<int\> to set an integer value into the record data: setValue<int>(num)
* @param[in] newValue The value of type T to copy to the record data
* @param[in] valueOffset An optional parameter that specifies where to start setting the record data (default set to 0). For example:
* if record data is 20 bytes long and you only need to set the 4 last bytes as integer then use this method like this:
* setValue<int>(num, 16)
* @return True if value was set successfully or false if the size of T is larger than the record data size
*/
template<typename T>
bool setValue(T newValue, int valueOffset = 0)
{
if (getDataSize() < sizeof(T))
return false;
memcpy(m_Data->recordValue + valueOffset, &newValue, sizeof(T));
return true;
}
/**
* @return The total size of the TLV record (in bytes)
*/
virtual size_t getTotalSize() const = 0;
/**
* @return The size of the record value (meaning the size of the 'V' part in TLV)
*/
virtual size_t getDataSize() const = 0;
};
/**
* @class TLVRecordReader
* A class for reading TLV records data out of a byte stream. This class contains helper methods for retrieving and
* counting TLV records. This is a template class that expects template argument class derived from TLVRecord.
*/
template<typename TLVRecordType>
class TLVRecordReader
{
private:
mutable size_t m_RecordCount;
public:
/**
* A default c'tor for this class
*/
TLVRecordReader() { m_RecordCount = (size_t)-1; }
/**
* A default copy c'tor for this class
*/
TLVRecordReader(const TLVRecordReader& other)
{
m_RecordCount = other.m_RecordCount;
}
/**
* A d'tor for this class which currently does nothing
*/
virtual ~TLVRecordReader() { }
/**
* Overload of the assignment operator for this class
* @param[in] other The TLVRecordReader instance to assign
*/
TLVRecordReader& operator=(const TLVRecordReader& other)
{
m_RecordCount = other.m_RecordCount;
return *this;
}
/**
* Get the first TLV record out of a byte stream
* @param[in] tlvDataBasePtr A pointer to the TLV data byte stream
* @param[in] tlvDataLen The TLV data byte stream length
* @return An instance of type TLVRecordType that contains the first TLV record. If tlvDataBasePtr is NULL or
* tlvDataLen is zero the returned TLVRecordType instance will be logically NULL, meaning TLVRecordType.isNull() will
* return true
*/
TLVRecordType getFirstTLVRecord(uint8_t* tlvDataBasePtr, size_t tlvDataLen) const
{
// In most cases tlvDataLen is not zero and the size is correct therefore the overhead is not significant if the checks will be done later
TLVRecordType resRec(tlvDataBasePtr); // for NRVO optimization
// check if there are records at all and the total size is not zero
if (tlvDataLen == 0 || resRec.getTotalSize() == 0)
resRec.assign(NULL);
return resRec;
}
/**
* Get a TLV record that follows a given TLV record in a byte stream
* @param[in] record A given TLV record
* @param[in] tlvDataBasePtr A pointer to the TLV data byte stream
* @param[in] tlvDataLen The TLV data byte stream length
* @return An instance of type TLVRecordType that wraps the record following the record given as input. If the
* input record.isNull() is true or if the next record is out of bounds of the byte stream, a logical NULL instance
* of TLVRecordType will be returned, meaning TLVRecordType.isNull() will return true
*/
TLVRecordType getNextTLVRecord(TLVRecordType& record, uint8_t* tlvDataBasePtr, size_t tlvDataLen) const
{
TLVRecordType resRec(NULL); // for NRVO optimization
if (record.isNull())
return resRec;
// record pointer is out-bounds of the TLV records memory
if ((record.getRecordBasePtr() - tlvDataBasePtr) < 0)
return resRec;
// record pointer is out-bounds of the TLV records memory
if (record.getRecordBasePtr() - tlvDataBasePtr + (int)record.getTotalSize() >= (int)tlvDataLen)
return resRec;
resRec.assign(record.getRecordBasePtr() + record.getTotalSize());
if (resRec.getTotalSize() == 0)
resRec.assign(NULL);
return resRec;
}
/**
* Search for the first TLV record that corresponds to a given record type (the 'T' in __Type__-Length-Value)
* @param[in] recordType The record type to search for
* @param[in] tlvDataBasePtr A pointer to the TLV data byte stream
* @param[in] tlvDataLen The TLV data byte stream length
* @return An instance of type TLVRecordType that contains the result record. If record was not found a logical
* NULL instance of TLVRecordType will be returned, meaning TLVRecordType.isNull() will return true
*/
TLVRecordType getTLVRecord(uint32_t recordType, uint8_t* tlvDataBasePtr, size_t tlvDataLen) const
{
TLVRecordType curRec = getFirstTLVRecord(tlvDataBasePtr, tlvDataLen);
while (!curRec.isNull())
{
if (curRec.getType() == recordType)
{
return curRec;
}
curRec = getNextTLVRecord(curRec, tlvDataBasePtr, tlvDataLen);
}
curRec.assign(NULL);
return curRec; // for NRVO optimization
}
/**
* Get the TLV record count in a given TLV data byte stream. For efficiency purposes the count is being cached
* so only the first call to this method will go over all the TLV records, while all consequent calls will return
* the cached number. This implies that if there is a change in the number of records, it's the user's responsibility
* to call changeTLVRecordCount() with the record count change
* @param[in] tlvDataBasePtr A pointer to the TLV data byte stream
* @param[in] tlvDataLen The TLV data byte stream length
* @return The TLV record count
*/
size_t getTLVRecordCount(uint8_t* tlvDataBasePtr, size_t tlvDataLen) const
{
if (m_RecordCount != (size_t)-1)
return m_RecordCount;
m_RecordCount = 0;
TLVRecordType curRec = getFirstTLVRecord(tlvDataBasePtr, tlvDataLen);
while (!curRec.isNull())
{
m_RecordCount++;
curRec = getNextTLVRecord(curRec, tlvDataBasePtr, tlvDataLen);
}
return m_RecordCount;
}
/**
* As described in getTLVRecordCount(), the TLV record count is being cached for efficiency purposes. So if the
* number of TLV records change, it's the user's responsibility to call this method with the number of TLV records
* being added or removed. If records were added the change should be a positive number, or a negative number
* if records were removed
* @param[in] changedBy Number of records that were added or removed
*/
void changeTLVRecordCount(int changedBy) { if (m_RecordCount != (size_t)-1) m_RecordCount += changedBy; }
};
/**
* @class TLVRecordBuilder
* A base class for building Type-Length-Value (TLV) records. This builder receives the record parameters in its c'tor,
* builds the record raw buffer and provides a method to build a TLVRecord object out of it. Please notice this is
* a base class that lacks the capability of actually building TLVRecord objects and also cannot be instantiated. The
* reason for that is that different protocols build TLV records in different ways, so these missing capabilities will
* be implemented by the derived classes which are specific to each protocol. This class only provides the common
* infrastructure that will be used by them
*/
class TLVRecordBuilder
{
protected:
TLVRecordBuilder();
TLVRecordBuilder(uint32_t recType, const uint8_t* recValue, uint8_t recValueLen);
TLVRecordBuilder(uint32_t recType, uint8_t recValue);
TLVRecordBuilder(uint32_t recType, uint16_t recValue);
TLVRecordBuilder(uint32_t recType, uint32_t recValue);
TLVRecordBuilder(uint32_t recType, const IPv4Address& recValue);
TLVRecordBuilder(uint32_t recType, const std::string& recValue, bool valueIsHexString = false);
TLVRecordBuilder(const TLVRecordBuilder& other);
TLVRecordBuilder& operator=(const TLVRecordBuilder& other);
virtual ~TLVRecordBuilder();
void init(uint32_t recType, const uint8_t* recValue, size_t recValueLen);
uint8_t* m_RecValue;
size_t m_RecValueLen;
uint32_t m_RecType;
private:
void copyData(const TLVRecordBuilder& other);
};
}
#endif // PACKETPP_TLV_DATA