|
|
|
|
// Copyright (c) 2012 The Bitcoin developers
|
|
|
|
|
// Distributed under the MIT/X11 software license, see the accompanying
|
|
|
|
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
|
#ifndef BITCOIN_BLOOM_H
|
|
|
|
|
#define BITCOIN_BLOOM_H
|
|
|
|
|
|
|
|
|
|
#include <vector>
|
|
|
|
|
|
|
|
|
|
#include "uint256.h"
|
|
|
|
|
#include "serialize.h"
|
|
|
|
|
|
|
|
|
|
class COutPoint;
|
|
|
|
|
class CTransaction;
|
|
|
|
|
|
|
|
|
|
// 20,000 items with fp rate < 0.1% or 10,000 items and <0.0001%
|
|
|
|
|
static const unsigned int MAX_BLOOM_FILTER_SIZE = 36000; // bytes
|
|
|
|
|
static const unsigned int MAX_HASH_FUNCS = 50;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* BloomFilter is a probabilistic filter which SPV clients provide
|
|
|
|
|
* so that we can filter the transactions we sends them.
|
|
|
|
|
*
|
|
|
|
|
* This allows for significantly more efficient transaction and block downloads.
|
|
|
|
|
*
|
|
|
|
|
* Because bloom filters are probabilistic, an SPV node can increase the false-
|
|
|
|
|
* positive rate, making us send them transactions which aren't actually theirs,
|
|
|
|
|
* allowing clients to trade more bandwidth for more privacy by obfuscating which
|
|
|
|
|
* keys are owned by them.
|
|
|
|
|
*/
|
|
|
|
|
class CBloomFilter
|
|
|
|
|
{
|
|
|
|
|
private:
|
|
|
|
|
std::vector<unsigned char> vData;
|
|
|
|
|
unsigned int nHashFuncs;
|
|
|
|
|
|
|
|
|
|
unsigned int Hash(unsigned int nHashNum, const std::vector<unsigned char>& vDataToHash) const;
|
|
|
|
|
|
|
|
|
|
public:
|
|
|
|
|
// 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.
|
|
|
|
|
// This will apply if nFPRate is very low or nElements is unreasonably high.
|
|
|
|
|
CBloomFilter(unsigned int nElements, double nFPRate);
|
|
|
|
|
// Using a filter initialized with this results in undefined behavior
|
|
|
|
|
// Should only be used for deserialization
|
|
|
|
|
CBloomFilter() {}
|
|
|
|
|
|
|
|
|
|
IMPLEMENT_SERIALIZE
|
|
|
|
|
(
|
|
|
|
|
READWRITE(vData);
|
|
|
|
|
READWRITE(nHashFuncs);
|
|
|
|
|
)
|
|
|
|
|
|
|
|
|
|
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;
|
|
|
|
|
|
|
|
|
|
// 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)
|
|
|
|
|
bool IsWithinSizeConstraints() const;
|
|
|
|
|
|
|
|
|
|
// Also adds any outputs which match the filter to the filter (to match their spending txes)
|
|
|
|
|
bool IsRelevantAndUpdate(const CTransaction& tx, const uint256& hash);
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
#endif /* BITCOIN_BLOOM_H */
|
