diff options
author | MarcoFalke <falke.marco@gmail.com> | 2021-09-29 17:22:44 +0200 |
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committer | MarcoFalke <falke.marco@gmail.com> | 2021-10-05 11:10:37 +0200 |
commit | fa1e5de2db2c7c95b96773a4ac231ab4249317e9 (patch) | |
tree | 310df62d3f7aea8b643f9b01e9caf2a3a9490e25 /src/bloom.h | |
parent | fac303c504ab19b863fddc7a0093068fee9d4ef3 (diff) |
scripted-diff: Move bloom to src/common
-BEGIN VERIFY SCRIPT-
# Move to directory
mkdir src/common
git mv src/bloom.cpp src/common/
git mv src/bloom.h src/common/
# Replace occurrences
sed -i 's|\<bloom\.cpp\>|common/bloom.cpp|g' $(git grep -l 'bloom.cpp')
sed -i 's|\<bloom\.h\>|common/bloom.h|g' $(git grep -l 'bloom.h')
sed -i 's|BITCOIN_BLOOM_H|BITCOIN_COMMON_BLOOM_H|g' $(git grep -l 'BLOOM_H')
-END VERIFY SCRIPT-
Diffstat (limited to 'src/bloom.h')
-rw-r--r-- | src/bloom.h | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/src/bloom.h b/src/bloom.h deleted file mode 100644 index 422646d8b9..0000000000 --- a/src/bloom.h +++ /dev/null @@ -1,127 +0,0 @@ -// Copyright (c) 2012-2020 The Bitcoin Core developers -// Distributed under the MIT 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 <serialize.h> -#include <span.h> - -#include <vector> - -class COutPoint; -class CTransaction; - -//! 20,000 items with fp rate < 0.1% or 10,000 items and <0.0001% -static constexpr unsigned int MAX_BLOOM_FILTER_SIZE = 36000; // bytes -static constexpr unsigned int MAX_HASH_FUNCS = 50; - -/** - * First two bits of nFlags control how much IsRelevantAndUpdate actually updates - * The remaining bits are reserved - */ -enum bloomflags -{ - BLOOM_UPDATE_NONE = 0, - BLOOM_UPDATE_ALL = 1, - // Only adds outpoints to the filter if the output is a pay-to-pubkey/pay-to-multisig script - BLOOM_UPDATE_P2PUBKEY_ONLY = 2, - BLOOM_UPDATE_MASK = 3, -}; - -/** - * 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. - */ -class CBloomFilter -{ -private: - std::vector<unsigned char> vData; - unsigned int nHashFuncs; - unsigned int nTweak; - unsigned char nFlags; - - unsigned int Hash(unsigned int nHashNum, Span<const 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. - * 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) - */ - CBloomFilter(const unsigned int nElements, const double nFPRate, const unsigned int nTweak, unsigned char nFlagsIn); - CBloomFilter() : nHashFuncs(0), nTweak(0), nFlags(0) {} - - SERIALIZE_METHODS(CBloomFilter, obj) { READWRITE(obj.vData, obj.nHashFuncs, obj.nTweak, obj.nFlags); } - - void insert(Span<const unsigned char> vKey); - void insert(const COutPoint& outpoint); - - bool contains(Span<const unsigned char> vKey) const; - bool contains(const COutPoint& outpoint) 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); -}; - -/** - * RollingBloomFilter is a probabilistic "keep track of most recently inserted" set. - * Construct it with the number of items to keep track of, and a false-positive - * rate. Unlike CBloomFilter, by default nTweak is set to a cryptographically - * secure random value for you. Similarly rather than clear() the method - * reset() is provided, which also changes nTweak to decrease the impact of - * false-positives. - * - * contains(item) will always return true if item was one of the last N to 1.5*N - * insert()'ed ... but may also return true for items that were not inserted. - * - * It needs around 1.8 bytes per element per factor 0.1 of false positive rate. - * For example, if we want 1000 elements, we'd need: - * - ~1800 bytes for a false positive rate of 0.1 - * - ~3600 bytes for a false positive rate of 0.01 - * - ~5400 bytes for a false positive rate of 0.001 - * - * If we make these simplifying assumptions: - * - logFpRate / log(0.5) doesn't get rounded or clamped in the nHashFuncs calculation - * - nElements is even, so that nEntriesPerGeneration == nElements / 2 - * - * Then we get a more accurate estimate for filter bytes: - * - * 3/(log(256)*log(2)) * log(1/fpRate) * nElements - */ -class CRollingBloomFilter -{ -public: - CRollingBloomFilter(const unsigned int nElements, const double nFPRate); - - void insert(Span<const unsigned char> vKey); - bool contains(Span<const unsigned char> vKey) const; - - void reset(); - -private: - int nEntriesPerGeneration; - int nEntriesThisGeneration; - int nGeneration; - std::vector<uint64_t> data; - unsigned int nTweak; - int nHashFuncs; -}; - -#endif // BITCOIN_BLOOM_H |