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https://github.com/PurpleI2P/i2pd
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implement simple bloom filter
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69
BloomFilter.cpp
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69
BloomFilter.cpp
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#include "BloomFilter.h"
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#include "I2PEndian.h"
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#include <array>
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#include <openssl/sha.h>
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namespace i2p
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{
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namespace util
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{
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/** @brief decaying bloom filter implementation */
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class DecayingBloomFilter : public IBloomFilter
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{
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public:
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DecayingBloomFilter(const std::size_t size)
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{
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m_Size = size;
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m_Data = new uint8_t[size];
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}
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/** @brief implements IBloomFilter::~IBloomFilter */
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~DecayingBloomFilter()
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{
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delete [] m_Data;
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}
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/** @brief implements IBloomFilter::Add */
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bool Add(const uint8_t * data, std::size_t len)
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{
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std::size_t idx;
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uint8_t mask;
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Get(data, len, idx, mask);
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if(m_Data[idx] & mask) return false; // filter hit
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m_Data[idx] |= mask;
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return true;
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}
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/** @brief implements IBloomFilter::Decay */
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void Decay()
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{
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// reset bloom filter buffer
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memset(m_Data, 0, m_Size);
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}
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private:
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/** @brief get bit index for for data */
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void Get(const uint8_t * data, std::size_t len, std::size_t & idx, uint8_t & bm)
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{
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bm = 1;
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uint8_t digest[32];
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// TODO: use blake2 because it's faster
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SHA256(data, len, digest);
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uint64_t i = buf64toh(digest);
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idx = i % m_Size;
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bm <<= (i % 8);
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}
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uint8_t * m_Data;
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std::size_t m_Size;
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};
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BloomFilterPtr BloomFilter(std::size_t capacity)
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{
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return std::make_shared<DecayingBloomFilter>(capacity);
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}
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}
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}
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31
BloomFilter.h
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31
BloomFilter.h
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#ifndef BLOOM_FILTER_H_
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#define BLOOM_FILTER_H_
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#include <memory>
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#include <cstdint>
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namespace i2p
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{
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namespace util
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{
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/** @brief interface for bloom filter */
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struct IBloomFilter
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{
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/** @brief destructor */
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virtual ~IBloomFilter();
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/** @brief add entry to bloom filter, return false if filter hit otherwise return true */
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virtual bool Add(const uint8_t * data, std::size_t len) = 0;
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/** @brief optionally decay old entries */
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virtual void Decay();
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};
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typedef std::shared_ptr<IBloomFilter> BloomFilterPtr;
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/** @brief create bloom filter */
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BloomFilterPtr BloomFilter(std::size_t capacity = 1024 * 8);
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}
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}
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#endif
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@ -26,6 +26,7 @@ set ( CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake_modules" )
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set ( CMAKE_SOURCE_DIR ".." )
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set (LIBI2PD_SRC
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"${CMAKE_SOURCE_DIR}/BloomFilter.cpp"
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"${CMAKE_SOURCE_DIR}/Config.cpp"
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"${CMAKE_SOURCE_DIR}/Crypto.cpp"
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"${CMAKE_SOURCE_DIR}/Garlic.cpp"
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@ -1,5 +1,5 @@
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LIB_SRC = \
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Gzip.cpp Crypto.cpp Datagram.cpp Garlic.cpp I2NPProtocol.cpp LeaseSet.cpp \
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BloomFilter.cpp Gzip.cpp Crypto.cpp Datagram.cpp Garlic.cpp I2NPProtocol.cpp LeaseSet.cpp \
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Log.cpp NTCPSession.cpp NetDb.cpp NetDbRequests.cpp Profiling.cpp \
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Reseed.cpp RouterContext.cpp RouterInfo.cpp Signature.cpp SSU.cpp \
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SSUSession.cpp SSUData.cpp Streaming.cpp Identity.cpp TransitTunnel.cpp \
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