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Merge pull request #6256
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65b9454 Use best header chain timestamps to detect partitioning (Gavin Andresen)
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laanwj committed Jun 12, 2015
2 parents ebab5d3 + 65b9454 commit 8ccc07c
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Showing 4 changed files with 16 additions and 14 deletions.
2 changes: 1 addition & 1 deletion src/init.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -1425,7 +1425,7 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
// Monitor the chain, and alert if we get blocks much quicker or slower than expected
int64_t nPowTargetSpacing = Params().GetConsensus().nPowTargetSpacing;
CScheduler::Function f = boost::bind(&PartitionCheck, &IsInitialBlockDownload,
boost::ref(cs_main), boost::cref(chainActive), nPowTargetSpacing);
boost::ref(cs_main), boost::cref(pindexBestHeader), nPowTargetSpacing);
scheduler.scheduleEvery(f, nPowTargetSpacing);

#ifdef ENABLE_WALLET
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16 changes: 10 additions & 6 deletions src/main.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -1723,9 +1723,10 @@ void ThreadScriptCheck() {
// we're being fed a bad chain (blocks being generated much
// too slowly or too quickly).
//
void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const CChain& chain, int64_t nPowTargetSpacing)
void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const CBlockIndex *const &bestHeader,
int64_t nPowTargetSpacing)
{
if (initialDownloadCheck()) return;
if (bestHeader == NULL || initialDownloadCheck()) return;

static int64_t lastAlertTime = 0;
int64_t now = GetAdjustedTime();
Expand All @@ -1741,10 +1742,13 @@ void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const
int64_t startTime = GetAdjustedTime()-SPAN_SECONDS;

LOCK(cs);
int h = chain.Height();
while (h > 0 && chain[h]->GetBlockTime() >= startTime)
--h;
int nBlocks = chain.Height()-h;
const CBlockIndex* i = bestHeader;
int nBlocks = 0;
while (i->GetBlockTime() >= startTime) {
++nBlocks;
i = i->pprev;
if (i == NULL) return; // Ran out of chain, we must not be fully sync'ed
}

// How likely is it to find that many by chance?
double p = boost::math::pdf(poisson, nBlocks);
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2 changes: 1 addition & 1 deletion src/main.h
Original file line number Diff line number Diff line change
Expand Up @@ -186,7 +186,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle);
/** Run an instance of the script checking thread */
void ThreadScriptCheck();
/** Try to detect Partition (network isolation) attacks against us */
void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const CChain& chain, int64_t nPowTargetSpacing);
void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const CBlockIndex *const &bestHeader, int64_t nPowTargetSpacing);
/** Check whether we are doing an initial block download (synchronizing from disk or network) */
bool IsInitialBlockDownload();
/** Format a string that describes several potential problems detected by the core */
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10 changes: 4 additions & 6 deletions src/test/alert_tests.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -201,7 +201,6 @@ BOOST_AUTO_TEST_CASE(PartitionAlert)
{
// Test PartitionCheck
CCriticalSection csDummy;
CChain chainDummy;
CBlockIndex indexDummy[100];
CChainParams& params = Params(CBaseChainParams::MAIN);
int64_t nPowTargetSpacing = params.GetConsensus().nPowTargetSpacing;
Expand All @@ -220,17 +219,16 @@ BOOST_AUTO_TEST_CASE(PartitionAlert)
// Other members don't matter, the partition check code doesn't
// use them
}
chainDummy.SetTip(&indexDummy[99]);

// Test 1: chain with blocks every nPowTargetSpacing seconds,
// as normal, no worries:
PartitionCheck(falseFunc, csDummy, chainDummy, nPowTargetSpacing);
PartitionCheck(falseFunc, csDummy, &indexDummy[99], nPowTargetSpacing);
BOOST_CHECK(strMiscWarning.empty());

// Test 2: go 3.5 hours without a block, expect a warning:
now += 3*60*60+30*60;
SetMockTime(now);
PartitionCheck(falseFunc, csDummy, chainDummy, nPowTargetSpacing);
PartitionCheck(falseFunc, csDummy, &indexDummy[99], nPowTargetSpacing);
BOOST_CHECK(!strMiscWarning.empty());
BOOST_TEST_MESSAGE(std::string("Got alert text: ")+strMiscWarning);
strMiscWarning = "";
Expand All @@ -239,7 +237,7 @@ BOOST_AUTO_TEST_CASE(PartitionAlert)
// code:
now += 60*10;
SetMockTime(now);
PartitionCheck(falseFunc, csDummy, chainDummy, nPowTargetSpacing);
PartitionCheck(falseFunc, csDummy, &indexDummy[99], nPowTargetSpacing);
BOOST_CHECK(strMiscWarning.empty());

// Test 4: get 2.5 times as many blocks as expected:
Expand All @@ -248,7 +246,7 @@ BOOST_AUTO_TEST_CASE(PartitionAlert)
int64_t quickSpacing = nPowTargetSpacing*2/5;
for (int i = 0; i < 100; i++) // Tweak chain timestamps:
indexDummy[i].nTime = now - (100-i)*quickSpacing;
PartitionCheck(falseFunc, csDummy, chainDummy, nPowTargetSpacing);
PartitionCheck(falseFunc, csDummy, &indexDummy[99], nPowTargetSpacing);
BOOST_CHECK(!strMiscWarning.empty());
BOOST_TEST_MESSAGE(std::string("Got alert text: ")+strMiscWarning);
strMiscWarning = "";
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