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-rw-r--r--src/bloom.cpp19
-rw-r--r--src/bloom.h12
-rw-r--r--src/main.cpp2
-rw-r--r--src/net.cpp2
-rw-r--r--src/test/bloom_tests.cpp6
5 files changed, 29 insertions, 12 deletions
diff --git a/src/bloom.cpp b/src/bloom.cpp
index 3f50b1da91..89959d7326 100644
--- a/src/bloom.cpp
+++ b/src/bloom.cpp
@@ -8,6 +8,7 @@
#include "hash.h"
#include "script/script.h"
#include "script/standard.h"
+#include "random.h"
#include "streams.h"
#include <math.h>
@@ -121,6 +122,12 @@ void CBloomFilter::clear()
isEmpty = true;
}
+void CBloomFilter::reset(unsigned int nNewTweak)
+{
+ clear();
+ nTweak = nNewTweak;
+}
+
bool CBloomFilter::IsWithinSizeConstraints() const
{
return vData.size() <= MAX_BLOOM_FILTER_SIZE && nHashFuncs <= MAX_HASH_FUNCS;
@@ -217,7 +224,8 @@ CRollingBloomFilter::CRollingBloomFilter(unsigned int nElements, double fpRate,
// inserted, so at least one always contains the last nElements
// inserted.
nBloomSize = nElements * 2;
- nInsertions = 0;
+
+ reset(nTweak);
}
void CRollingBloomFilter::insert(const std::vector<unsigned char>& vKey)
@@ -254,9 +262,12 @@ bool CRollingBloomFilter::contains(const uint256& hash) const
return contains(data);
}
-void CRollingBloomFilter::clear()
+void CRollingBloomFilter::reset(unsigned int nNewTweak)
{
- b1.clear();
- b2.clear();
+ if (!nNewTweak)
+ nNewTweak = GetRand(std::numeric_limits<unsigned int>::max());
+
+ b1.reset(nNewTweak);
+ b2.reset(nNewTweak);
nInsertions = 0;
}
diff --git a/src/bloom.h b/src/bloom.h
index 0daa3728ed..12bf6d99a8 100644
--- a/src/bloom.h
+++ b/src/bloom.h
@@ -89,6 +89,7 @@ public:
bool contains(const uint256& hash) const;
void clear();
+ void reset(unsigned int nNewTweak);
//! 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)
@@ -103,7 +104,11 @@ public:
/**
* 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.
+ * 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 things
* insert()'ed ... but may also return true for items that were not inserted.
@@ -111,14 +116,15 @@ public:
class CRollingBloomFilter
{
public:
- CRollingBloomFilter(unsigned int nElements, double nFPRate, unsigned int nTweak);
+ CRollingBloomFilter(unsigned int nElements, double nFPRate,
+ unsigned int nTweak = 0);
void insert(const std::vector<unsigned char>& vKey);
void insert(const uint256& hash);
bool contains(const std::vector<unsigned char>& vKey) const;
bool contains(const uint256& hash) const;
- void clear();
+ void reset(unsigned int nNewTweak = 0);
private:
unsigned int nBloomSize;
diff --git a/src/main.cpp b/src/main.cpp
index 7477d08b18..01b62bdf60 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -4812,7 +4812,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
{
// Periodically clear addrKnown to allow refresh broadcasts
if (nLastRebroadcast)
- pnode->addrKnown.clear();
+ pnode->addrKnown.reset();
// Rebroadcast our address
AdvertizeLocal(pnode);
diff --git a/src/net.cpp b/src/net.cpp
index 3cece520de..176fd7195b 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -2060,7 +2060,7 @@ unsigned int SendBufferSize() { return 1000*GetArg("-maxsendbuffer", 1*1000); }
CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNameIn, bool fInboundIn) :
ssSend(SER_NETWORK, INIT_PROTO_VERSION),
- addrKnown(5000, 0.001, insecure_rand()),
+ addrKnown(5000, 0.001),
setInventoryKnown(SendBufferSize() / 1000)
{
nServices = 0;
diff --git a/src/test/bloom_tests.cpp b/src/test/bloom_tests.cpp
index 1bda8a7ea1..d927be6b81 100644
--- a/src/test/bloom_tests.cpp
+++ b/src/test/bloom_tests.cpp
@@ -469,7 +469,7 @@ static std::vector<unsigned char> RandomData()
BOOST_AUTO_TEST_CASE(rolling_bloom)
{
// last-100-entry, 1% false positive:
- CRollingBloomFilter rb1(100, 0.01, 0);
+ CRollingBloomFilter rb1(100, 0.01, 1);
// Overfill:
static const int DATASIZE=399;
@@ -500,7 +500,7 @@ BOOST_AUTO_TEST_CASE(rolling_bloom)
BOOST_CHECK(nHits < 175);
BOOST_CHECK(rb1.contains(data[DATASIZE-1]));
- rb1.clear();
+ rb1.reset(1);
BOOST_CHECK(!rb1.contains(data[DATASIZE-1]));
// Now roll through data, make sure last 100 entries
@@ -527,7 +527,7 @@ BOOST_AUTO_TEST_CASE(rolling_bloom)
BOOST_CHECK(nHits < 100);
// last-1000-entry, 0.01% false positive:
- CRollingBloomFilter rb2(1000, 0.001, 0);
+ CRollingBloomFilter rb2(1000, 0.001, 1);
for (int i = 0; i < DATASIZE; i++) {
rb2.insert(data[i]);
}