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authorPieter Wuille <pieter.wuille@gmail.com>2014-09-06 21:16:25 +0200
committerPieter Wuille <pieter.wuille@gmail.com>2014-10-14 15:42:01 -0700
commitf244c99c96636136678f17e7ef3952a864613ad0 (patch)
tree46fe2c8f9c9b9f5d16e8b9804e9c3c1d3b4a6e45 /src
parentad6e6017127ec2a3a8d1a71aaab7a6e945c5b0f9 (diff)
Remove CheckMinWork, as we always know all parent headers
Diffstat (limited to 'src')
-rw-r--r--src/main.cpp17
-rw-r--r--src/pow.cpp33
-rw-r--r--src/pow.h2
-rw-r--r--src/test/DoS_tests.cpp45
4 files changed, 0 insertions, 97 deletions
diff --git a/src/main.cpp b/src/main.cpp
index 604ca670ef..dba4292f50 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2329,23 +2329,6 @@ bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, CBloc
return true;
}
- CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint();
- if (pcheckpoint && block.hashPrevBlock != (chainActive.Tip() ? chainActive.Tip()->GetBlockHash() : uint256(0)))
- {
- // Extra checks to prevent "fill up memory by spamming with bogus blocks"
- int64_t deltaTime = block.GetBlockTime() - pcheckpoint->GetBlockTime();
- if (deltaTime < 0)
- {
- return state.DoS(100, error("%s : block with timestamp before last checkpoint", __func__),
- REJECT_CHECKPOINT, "time-too-old");
- }
- if (!CheckMinWork(block.nBits, pcheckpoint->nBits, deltaTime))
- {
- return state.DoS(100, error("%s : block with too little proof-of-work", __func__),
- REJECT_INVALID, "bad-diffbits");
- }
- }
-
// Get prev block index
CBlockIndex* pindexPrev = NULL;
int nHeight = 0;
diff --git a/src/pow.cpp b/src/pow.cpp
index d50222849c..75fbfc6a6d 100644
--- a/src/pow.cpp
+++ b/src/pow.cpp
@@ -98,39 +98,6 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits)
return true;
}
-//
-// true if nBits is greater than the minimum amount of work that could
-// possibly be required deltaTime after minimum work required was nBase
-//
-bool CheckMinWork(unsigned int nBits, unsigned int nBase, int64_t deltaTime)
-{
- bool fOverflow = false;
- uint256 bnNewBlock;
- bnNewBlock.SetCompact(nBits, NULL, &fOverflow);
- if (fOverflow)
- return false;
-
- const uint256 &bnLimit = Params().ProofOfWorkLimit();
- // Testnet has min-difficulty blocks
- // after Params().TargetSpacing()*2 time between blocks:
- if (Params().AllowMinDifficultyBlocks() && deltaTime > Params().TargetSpacing()*2)
- return bnNewBlock <= bnLimit;
-
- uint256 bnResult;
- bnResult.SetCompact(nBase);
- while (deltaTime > 0 && bnResult < bnLimit)
- {
- // Maximum 400% adjustment...
- bnResult *= 4;
- // ... in best-case exactly 4-times-normal target time
- deltaTime -= Params().TargetTimespan()*4;
- }
- if (bnResult > bnLimit)
- bnResult = bnLimit;
-
- return bnNewBlock <= bnResult;
-}
-
void UpdateTime(CBlockHeader* pblock, const CBlockIndex* pindexPrev)
{
pblock->nTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
diff --git a/src/pow.h b/src/pow.h
index 5d91108ac4..233d1f3795 100644
--- a/src/pow.h
+++ b/src/pow.h
@@ -16,8 +16,6 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
/** Check whether a block hash satisfies the proof-of-work requirement specified by nBits */
bool CheckProofOfWork(uint256 hash, unsigned int nBits);
-/** Check the work is more than the minimum a received block needs, without knowing its direct parent */
-bool CheckMinWork(unsigned int nBits, unsigned int nBase, int64_t deltaTime);
void UpdateTime(CBlockHeader* block, const CBlockIndex* pindexPrev);
diff --git a/src/test/DoS_tests.cpp b/src/test/DoS_tests.cpp
index 7bec12b665..f9746fdaa5 100644
--- a/src/test/DoS_tests.cpp
+++ b/src/test/DoS_tests.cpp
@@ -106,51 +106,6 @@ BOOST_AUTO_TEST_CASE(DoS_bantime)
BOOST_CHECK(!CNode::IsBanned(addr));
}
-static bool CheckNBits(unsigned int nbits1, int64_t time1, unsigned int nbits2, int64_t time2)\
-{
- if (time1 > time2)
- return CheckNBits(nbits2, time2, nbits1, time1);
- int64_t deltaTime = time2-time1;
-
- return CheckMinWork(nbits2, nbits1, deltaTime);
-}
-
-BOOST_AUTO_TEST_CASE(DoS_checknbits)
-{
- using namespace boost::assign; // for 'map_list_of()'
-
- // Timestamps,nBits from the bitcoin block chain.
- // These are the block-chain checkpoint blocks
- typedef std::map<int64_t, unsigned int> BlockData;
- BlockData chainData =
- map_list_of(1239852051,486604799)(1262749024,486594666)
- (1279305360,469854461)(1280200847,469830746)(1281678674,469809688)
- (1296207707,453179945)(1302624061,453036989)(1309640330,437004818)
- (1313172719,436789733);
-
- // Make sure CheckNBits considers every combination of block-chain-lock-in-points
- // "sane":
- BOOST_FOREACH(const BlockData::value_type& i, chainData)
- {
- BOOST_FOREACH(const BlockData::value_type& j, chainData)
- {
- BOOST_CHECK(CheckNBits(i.second, i.first, j.second, j.first));
- }
- }
-
- // Test a couple of insane combinations:
- BlockData::value_type firstcheck = *(chainData.begin());
- BlockData::value_type lastcheck = *(chainData.rbegin());
-
- // First checkpoint difficulty at or a while after the last checkpoint time should fail when
- // compared to last checkpoint
- BOOST_CHECK(!CheckNBits(firstcheck.second, lastcheck.first+60*10, lastcheck.second, lastcheck.first));
- BOOST_CHECK(!CheckNBits(firstcheck.second, lastcheck.first+60*60*24*14, lastcheck.second, lastcheck.first));
-
- // ... but OK if enough time passed for difficulty to adjust downward:
- BOOST_CHECK(CheckNBits(firstcheck.second, lastcheck.first+60*60*24*365*4, lastcheck.second, lastcheck.first));
-}
-
CTransaction RandomOrphan()
{
std::map<uint256, COrphanTx>::iterator it;