BloomFilter is a probabilistic filter which SPV clients provide so that we can filter the transactions we send them. More...

#include <bloom.h>

Public Member Functions
	CBloomFilter (const unsigned int nElements, const double nFPRate, const unsigned int nTweak, unsigned char nFlagsIn)
	Creates a new bloom filter which will provide the given fp rate when filled with the given number of elements Note that if the given parameters will result in a filter outside the bounds of the protocol limits, the filter created will be as close to the given parameters as possible within the protocol limits. More...

	CBloomFilter ()

template<typename Stream , typename Operation >
void	SerializationOp (Stream &s, Operation ser_action)

void	insert (const std::vector< unsigned char > &vKey)

void	insert (const COutPoint &outpoint)

void	insert (const uint256 &hash)

bool	contains (const std::vector< unsigned char > &vKey) const

bool	contains (const COutPoint &outpoint) const

bool	contains (const uint256 &hash) const

bool	contains (const uint160 &hash) const

void	clear ()

void	reset (const unsigned int nNewTweak)

bool	IsWithinSizeConstraints () const
	True if the size is <= MAX_BLOOM_FILTER_SIZE and the number of hash functions is <= MAX_HASH_FUNCS (catch a filter which was just deserialized which was too big) More...

bool	IsRelevantAndUpdate (const CTransaction &tx)
	Also adds any outputs which match the filter to the filter (to match their spending txes) More...

void	UpdateEmptyFull ()
	Checks for empty and full filters to avoid wasting cpu. More...

Public Attributes
	ADD_SERIALIZE_METHODS

Private Member Functions
unsigned int	Hash (unsigned int nHashNum, const std::vector< unsigned char > &vDataToHash) const

	CBloomFilter (const unsigned int nElements, const double nFPRate, const unsigned int nTweak)

bool	CheckScript (const CScript &script) const

bool	CheckSpecialTransactionMatchesAndUpdate (const CTransaction &tx)

Private Attributes
std::vector< unsigned char >	vData

bool	isFull

bool	isEmpty

unsigned int	nHashFuncs

unsigned int	nTweak

unsigned char	nFlags

Friends
class	CRollingBloomFilter

Detailed Description

BloomFilter is a probabilistic filter which SPV clients provide so that we can filter the transactions we send them.

This allows for significantly more efficient transaction and block downloads.

Because bloom filters are probabilistic, a SPV node can increase the false- positive rate, making us send it transactions which aren't actually its, allowing clients to trade more bandwidth for more privacy by obfuscating which keys are controlled by them.

Definition at line 46 of file bloom.h.

Constructor & Destructor Documentation

◆ CBloomFilter() [1/3]

CBloomFilter::CBloomFilter	(	const unsigned int	nElements,
		const double	nFPRate,
		const unsigned int	nTweak
	)

private

Definition at line 46 of file bloom.cpp.

◆ CBloomFilter() [2/3]

CBloomFilter::CBloomFilter	(	const unsigned int	nElements,
		const double	nFPRate,
		const unsigned int	nTweakIn,
		unsigned char	nFlagsIn
	)

Creates a new bloom filter which will provide the given fp rate when filled with the given number of elements Note that if the given parameters will result in a filter outside the bounds of the protocol limits, the filter created will be as close to the given parameters as possible within the protocol limits.

The ideal size for a bloom filter with a given number of elements and false positive rate is:

This will apply if nFPRate is very low or nElements is unreasonably high. nTweak is a constant which is added to the seed value passed to the hash function It should generally always be a random value (and is largely only exposed for unit testing) nFlags should be one of the BLOOM_UPDATE_* enums (not _MASK)

nElements * log(fp rate) / ln(2)^2 We ignore filter parameters which will create a bloom filter larger than the protocol limits The ideal number of hash functions is filter size * ln(2) / number of elements Again, we ignore filter parameters which will create a bloom filter with more hash functions than the protocol limits See https://en.wikipedia.org/wiki/Bloom_filter for an explanation of these formulas

Definition at line 25 of file bloom.cpp.

◆ CBloomFilter() [3/3]

CBloomFilter::CBloomFilter ( )

inline

Definition at line 77 of file bloom.h.

Member Function Documentation

◆ CheckScript()

bool CBloomFilter::CheckScript ( const CScript & script ) const

private

Definition at line 144 of file bloom.cpp.

References prevector< N, T, Size, Diff >::begin(), contains(), prevector< N, T, Size, Diff >::end(), and CScript::GetOp().

Referenced by CheckSpecialTransactionMatchesAndUpdate(), and IsRelevantAndUpdate().

◆ CheckSpecialTransactionMatchesAndUpdate()

bool CBloomFilter::CheckSpecialTransactionMatchesAndUpdate ( const CTransaction & tx )

private

◆ clear()

void CBloomFilter::clear ( )

Definition at line 125 of file bloom.cpp.

References isEmpty, isFull, and vData.

Referenced by CGovernanceManager::ProcessMessage(), CGovernanceManager::RequestGovernanceObject(), reset(), and CMasternodeSync::SendGovernanceSyncRequest().

◆ contains() [1/4]

bool CBloomFilter::contains ( const std::vector< unsigned char > & vKey ) const

Definition at line 89 of file bloom.cpp.

References Hash(), isEmpty, isFull, nHashFuncs, and vData.

Referenced by CheckScript(), CheckSpecialTransactionMatchesAndUpdate(), contains(), IsRelevantAndUpdate(), and CGovernanceManager::SyncSingleObjVotes().

◆ contains() [2/4]

bool CBloomFilter::contains ( const COutPoint & outpoint ) const

Definition at line 105 of file bloom.cpp.

References CDataStream::begin(), contains(), CDataStream::end(), PROTOCOL_VERSION, and SER_NETWORK.

◆ contains() [3/4]

bool CBloomFilter::contains ( const uint256 & hash ) const

Definition at line 113 of file bloom.cpp.

References base_blob< BITS >::begin(), contains(), and base_blob< BITS >::end().

◆ contains() [4/4]

bool CBloomFilter::contains ( const uint160 & hash ) const

Definition at line 119 of file bloom.cpp.

References base_blob< BITS >::begin(), contains(), and base_blob< BITS >::end().

◆ Hash()

unsigned int CBloomFilter::Hash	(	unsigned int	nHashNum,
		const std::vector< unsigned char > &	vDataToHash
	)		const

inlineprivate

Definition at line 56 of file bloom.cpp.

References MurmurHash3(), nTweak, and vData.

Referenced by contains(), and insert().

◆ insert() [1/3]

void CBloomFilter::insert ( const std::vector< unsigned char > & vKey )

Definition at line 62 of file bloom.cpp.

References Hash(), isEmpty, isFull, nHashFuncs, and vData.

Referenced by CheckSpecialTransactionMatchesAndUpdate(), insert(), IsRelevantAndUpdate(), and CGovernanceManager::RequestGovernanceObject().

◆ insert() [2/3]

void CBloomFilter::insert ( const COutPoint & outpoint )

Definition at line 75 of file bloom.cpp.

References CDataStream::begin(), CDataStream::end(), insert(), PROTOCOL_VERSION, and SER_NETWORK.

◆ insert() [3/3]

void CBloomFilter::insert ( const uint256 & hash )

Definition at line 83 of file bloom.cpp.

References base_blob< BITS >::begin(), base_blob< BITS >::end(), and insert().

◆ IsRelevantAndUpdate()

bool CBloomFilter::IsRelevantAndUpdate ( const CTransaction & tx )

Also adds any outputs which match the filter to the filter (to match their spending txes)

Definition at line 233 of file bloom.cpp.

References BLOOM_UPDATE_ALL, BLOOM_UPDATE_MASK, BLOOM_UPDATE_P2PUBKEY_ONLY, CheckScript(), CheckSpecialTransactionMatchesAndUpdate(), contains(), CTransaction::GetHash(), insert(), isEmpty, isFull, nFlags, CTxIn::prevout, CTxOut::scriptPubKey, CTxIn::scriptSig, Solver(), TX_MULTISIG, TX_PUBKEY, CTransaction::vin, and CTransaction::vout.

Referenced by CMerkleBlock::CMerkleBlock().

◆ IsWithinSizeConstraints()

bool CBloomFilter::IsWithinSizeConstraints ( ) const

True if the size is <= MAX_BLOOM_FILTER_SIZE and the number of hash functions is <= MAX_HASH_FUNCS (catch a filter which was just deserialized which was too big)

Definition at line 138 of file bloom.cpp.

References MAX_BLOOM_FILTER_SIZE, MAX_HASH_FUNCS, nHashFuncs, and vData.

◆ reset()

void CBloomFilter::reset ( const unsigned int nNewTweak )

Definition at line 132 of file bloom.cpp.

References clear(), and nTweak.

◆ SerializationOp()

template<typename Stream , typename Operation >

void CBloomFilter::SerializationOp	(	Stream &	s,
		Operation	ser_action
	)

inline

Definition at line 82 of file bloom.h.

References nFlags, nHashFuncs, nTweak, READWRITE, and vData.

◆ UpdateEmptyFull()

void CBloomFilter::UpdateEmptyFull ( )

Checks for empty and full filters to avoid wasting cpu.

Definition at line 288 of file bloom.cpp.

References immer::detail::dvektor::empty, isEmpty, isFull, and vData.

Referenced by CGovernanceManager::ProcessMessage().

Friends And Related Function Documentation

◆ CRollingBloomFilter

friend class CRollingBloomFilter

friend

Definition at line 60 of file bloom.h.

Member Data Documentation

◆ ADD_SERIALIZE_METHODS

CBloomFilter::ADD_SERIALIZE_METHODS

Definition at line 79 of file bloom.h.

◆ isEmpty

bool CBloomFilter::isEmpty

private

Definition at line 51 of file bloom.h.

Referenced by clear(), contains(), insert(), IsRelevantAndUpdate(), and UpdateEmptyFull().

◆ isFull

bool CBloomFilter::isFull

private

Definition at line 50 of file bloom.h.

Referenced by clear(), contains(), insert(), IsRelevantAndUpdate(), and UpdateEmptyFull().

◆ nFlags

unsigned char CBloomFilter::nFlags

private

Definition at line 54 of file bloom.h.

Referenced by CheckSpecialTransactionMatchesAndUpdate(), IsRelevantAndUpdate(), and SerializationOp().

◆ nHashFuncs

unsigned int CBloomFilter::nHashFuncs

private

Definition at line 52 of file bloom.h.

Referenced by contains(), insert(), IsWithinSizeConstraints(), and SerializationOp().

◆ nTweak

unsigned int CBloomFilter::nTweak

private

Definition at line 53 of file bloom.h.

Referenced by Hash(), reset(), and SerializationOp().

◆ vData

std::vector<unsigned char> CBloomFilter::vData

private

Definition at line 49 of file bloom.h.

Referenced by clear(), contains(), Hash(), insert(), IsWithinSizeConstraints(), SerializationOp(), and UpdateEmptyFull().

The documentation for this class was generated from the following files:

src/bloom.h
src/bloom.cpp

Dash Core Source Documentation (0.16.0.1)

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ CBloomFilter() [1/3]

◆ CBloomFilter() [2/3]

◆ CBloomFilter() [3/3]

Member Function Documentation

◆ CheckScript()

◆ CheckSpecialTransactionMatchesAndUpdate()

◆ clear()

◆ contains() [1/4]

◆ contains() [2/4]

◆ contains() [3/4]

◆ contains() [4/4]

◆ Hash()

◆ insert() [1/3]

◆ insert() [2/3]

◆ insert() [3/3]

◆ IsRelevantAndUpdate()

◆ IsWithinSizeConstraints()

◆ reset()

◆ SerializationOp()

◆ UpdateEmptyFull()

Friends And Related Function Documentation

◆ CRollingBloomFilter

Member Data Documentation

◆ ADD_SERIALIZE_METHODS

◆ isEmpty

◆ isFull

◆ nFlags

◆ nHashFuncs

◆ nTweak

◆ vData