aboutsummaryrefslogtreecommitdiff
path: root/main.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'main.cpp')
-rw-r--r--main.cpp146
1 files changed, 97 insertions, 49 deletions
diff --git a/main.cpp b/main.cpp
index 7a718c73dc..bfc45af28e 100644
--- a/main.cpp
+++ b/main.cpp
@@ -287,7 +287,7 @@ void EraseOrphanTx(uint256 hash)
//////////////////////////////////////////////////////////////////////////////
//
-// CTransaction
+// CTransaction and CTxIndex
//
bool CTransaction::ReadFromDisk(CTxDB& txdb, COutPoint prevout, CTxIndex& txindexRet)
@@ -678,7 +678,11 @@ bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMi
// Safety limits
unsigned int nSize = ::GetSerializeSize(*this, SER_NETWORK);
- if (GetSigOpCount() > 2 || nSize < 100)
+ // Checking ECDSA signatures is a CPU bottleneck, so to avoid denial-of-service
+ // attacks disallow transactions with more than one SigOp per 34 bytes.
+ // 34 bytes because a TxOut is:
+ // 20-byte address + 8 byte bitcoin amount + 5 bytes of ops + 1 byte script length
+ if (GetSigOpCount() > nSize / 34 || nSize < 100)
return error("AcceptToMemoryPool() : nonstandard transaction");
// Rather not work on nonstandard transactions
@@ -738,19 +742,29 @@ bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMi
if (nFees < GetMinFee(1000))
return error("AcceptToMemoryPool() : not enough fees");
- // Limit free transactions per 10 minutes
- if (nFees < CENT && GetBoolArg("-limitfreerelay"))
+ // Continuously rate-limit free transactions
+ // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
+ // be annoying or make other's transactions take longer to confirm.
+ if (nFees < CENT)
{
- static int64 nNextReset;
- static int64 nFreeCount;
- if (GetTime() > nNextReset)
+ static CCriticalSection cs;
+ static double dFreeCount;
+ static int64 nLastTime;
+ int64 nNow = GetTime();
+
+ CRITICAL_BLOCK(cs)
{
- nNextReset = GetTime() + 10 * 60;
- nFreeCount = 0;
+ // Use an exponentially decaying ~10-minute window:
+ dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime));
+ nLastTime = nNow;
+ // -limitfreerelay unit is thousand-bytes-per-minute
+ // At default rate it would take over a month to fill 1GB
+ if (dFreeCount > GetArg("-limitfreerelay", 15)*10*1000 && !IsFromMe())
+ return error("AcceptToMemoryPool() : free transaction rejected by rate limiter");
+ if (fDebug)
+ printf("Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
+ dFreeCount += nSize;
}
- if (nFreeCount > 150000 && !IsFromMe())
- return error("AcceptToMemoryPool() : free transaction rejected by rate limiter");
- nFreeCount += nSize;
}
}
@@ -1034,6 +1048,22 @@ void ResendWalletTransactions()
}
}
+int CTxIndex::GetDepthInMainChain() const
+{
+ // Read block header
+ CBlock block;
+ if (!block.ReadFromDisk(pos.nFile, pos.nBlockPos, false))
+ return 0;
+ // Find the block in the index
+ map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(block.GetHash());
+ if (mi == mapBlockIndex.end())
+ return 0;
+ CBlockIndex* pindex = (*mi).second;
+ if (!pindex || !pindex->IsInMainChain())
+ return 0;
+ return 1 + nBestHeight - pindex->nHeight;
+}
+
@@ -3331,18 +3361,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
int64 nValueIn = txPrev.vout[txin.prevout.n].nValue;
// Read block header
- int nConf = 0;
- CBlock block;
- if (block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
- {
- map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(block.GetHash());
- if (it != mapBlockIndex.end())
- {
- CBlockIndex* pindex = (*it).second;
- if (pindex->IsInMainChain())
- nConf = 1 + nBestHeight - pindex->nHeight;
- }
- }
+ int nConf = txindex.GetDepthInMainChain();
dPriority += (double)nValueIn * nConf;
@@ -3387,7 +3406,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
continue;
// Transaction fee required depends on block size
- bool fAllowFree = (nBlockSize + nTxSize < 4000 || dPriority > COIN * 144 / 250);
+ bool fAllowFree = (nBlockSize + nTxSize < 4000 || CTransaction::AllowFree(dPriority));
int64 nMinFee = tx.GetMinFee(nBlockSize, fAllowFree);
// Connecting shouldn't fail due to dependency on other memory pool transactions
@@ -3754,16 +3773,16 @@ bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, set<
int64 n = pcoin->GetCredit();
if (n <= 0)
continue;
- if (n < nTargetValue)
- {
- vValue.push_back(make_pair(n, pcoin));
- nTotalLower += n;
- }
- else if (n == nTargetValue)
+ if (n == nTargetValue)
{
setCoinsRet.insert(pcoin);
return true;
}
+ else if (n < nTargetValue + CENT)
+ {
+ vValue.push_back(make_pair(n, pcoin));
+ nTotalLower += n;
+ }
else if (n < nLowestLarger)
{
nLowestLarger = n;
@@ -3772,7 +3791,14 @@ bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, set<
}
}
- if (nTotalLower < nTargetValue)
+ if (nTotalLower == nTargetValue || nTotalLower == nTargetValue + CENT)
+ {
+ for (int i = 0; i < vValue.size(); ++i)
+ setCoinsRet.insert(vValue[i].second);
+ return true;
+ }
+
+ if (nTotalLower < nTargetValue + (pcoinLowestLarger ? CENT : 0))
{
if (pcoinLowestLarger == NULL)
return false;
@@ -3780,6 +3806,9 @@ bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, set<
return true;
}
+ if (nTotalLower >= nTargetValue + CENT)
+ nTargetValue += CENT;
+
// Solve subset sum by stochastic approximation
sort(vValue.rbegin(), vValue.rend());
vector<char> vfIncluded;
@@ -3845,8 +3874,18 @@ bool SelectCoins(int64 nTargetValue, set<CWalletTx*>& setCoinsRet)
-bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet)
+bool CreateTransaction(const vector<pair<CScript, int64> >& vecSend, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet)
{
+ int64 nValue = 0;
+ foreach (const PAIRTYPE(CScript, int64)& s, vecSend)
+ {
+ if (nValue < 0)
+ return false;
+ nValue += s.second;
+ }
+ if (vecSend.empty() || nValue < 0)
+ return false;
+
CRITICAL_BLOCK(cs_main)
{
// txdb must be opened before the mapWallet lock
@@ -3859,10 +3898,12 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
wtxNew.vin.clear();
wtxNew.vout.clear();
wtxNew.fFromMe = true;
- if (nValue < 0)
- return false;
- int64 nValueOut = nValue;
+
int64 nTotalValue = nValue + nFeeRet;
+ double dPriority = 0;
+ // vouts to the payees
+ foreach (const PAIRTYPE(CScript, int64)& s, vecSend)
+ wtxNew.vout.push_back(CTxOut(s.second, s.first));
// Choose coins to use
set<CWalletTx*> setCoins;
@@ -3870,12 +3911,11 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
return false;
int64 nValueIn = 0;
foreach(CWalletTx* pcoin, setCoins)
- nValueIn += pcoin->GetCredit();
-
- // Fill a vout to the payee
- bool fChangeFirst = GetRand(2);
- if (!fChangeFirst)
- wtxNew.vout.push_back(CTxOut(nValueOut, scriptPubKey));
+ {
+ int64 nCredit = pcoin->GetCredit();
+ nValueIn += nCredit;
+ dPriority += (double)nCredit * pcoin->GetDepthInMainChain();
+ }
// Fill a vout back to self with any change
int64 nChange = nValueIn - nTotalValue;
@@ -3894,19 +3934,18 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
// Fill a vout to ourself, using same address type as the payment
CScript scriptChange;
- if (scriptPubKey.GetBitcoinAddressHash160() != 0)
+ if (vecSend[0].first.GetBitcoinAddressHash160() != 0)
scriptChange.SetBitcoinAddress(vchPubKey);
else
scriptChange << vchPubKey << OP_CHECKSIG;
- wtxNew.vout.push_back(CTxOut(nChange, scriptChange));
+
+ // Insert change txn at random position:
+ vector<CTxOut>::iterator position = wtxNew.vout.begin()+GetRandInt(wtxNew.vout.size());
+ wtxNew.vout.insert(position, CTxOut(nChange, scriptChange));
}
else
reservekey.ReturnKey();
- // Fill a vout to the payee
- if (fChangeFirst)
- wtxNew.vout.push_back(CTxOut(nValueOut, scriptPubKey));
-
// Fill vin
foreach(CWalletTx* pcoin, setCoins)
for (int nOut = 0; nOut < pcoin->vout.size(); nOut++)
@@ -3925,10 +3964,12 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
unsigned int nBytes = ::GetSerializeSize(*(CTransaction*)&wtxNew, SER_NETWORK);
if (nBytes >= MAX_BLOCK_SIZE_GEN/5)
return false;
+ dPriority /= nBytes;
// Check that enough fee is included
int64 nPayFee = nTransactionFee * (1 + (int64)nBytes / 1000);
- int64 nMinFee = wtxNew.GetMinFee();
+ bool fAllowFree = CTransaction::AllowFree(dPriority);
+ int64 nMinFee = wtxNew.GetMinFee(1, fAllowFree);
if (nFeeRet < max(nPayFee, nMinFee))
{
nFeeRet = max(nPayFee, nMinFee);
@@ -3946,6 +3987,13 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
return true;
}
+bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet)
+{
+ vector< pair<CScript, int64> > vecSend;
+ vecSend.push_back(make_pair(scriptPubKey, nValue));
+ return CreateTransaction(vecSend, wtxNew, reservekey, nFeeRet);
+}
+
// Call after CreateTransaction unless you want to abort
bool CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey)
{
generated by cgit v1.2.3 (git 2.26.2) at 2024-09-01 14:45:51 +0000