dash/src/core.cpp
Tom Harding d640a3ceab Relay double-spends, subject to anti-DOS
Allows network wallets and other clients to see transactions that respend
a prevout already spent in an unconfirmed transaction in this node's mempool.

Knowledge of an attempted double-spend is of interest to recipients of the
first spend.  In some cases, it will allow these recipients to withhold
goods or services upon being alerted of a double-spend that deprives them
of payment.

As before, respends are not added to the mempool.

Anti-Denial-of-Service-Attack provisions:
 - Use a bloom filter to relay only one respend per mempool prevout
 - Rate-limit respend relays to a default of 100 thousand bytes/minute
 - Define tx2.IsEquivalentTo(tx1): equality when scriptSigs are not considered
 - Do not relay these equivalent transactions

Remove an unused variable declaration in txmempool.cpp.
2014-06-27 07:54:21 -07:00

318 lines
8.8 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "core.h"
#include "util.h"
std::string COutPoint::ToString() const
{
return strprintf("COutPoint(%s, %u)", hash.ToString().substr(0,10), n);
}
void COutPoint::print() const
{
LogPrintf("%s\n", ToString());
}
CTxIn::CTxIn(COutPoint prevoutIn, CScript scriptSigIn, unsigned int nSequenceIn)
{
prevout = prevoutIn;
scriptSig = scriptSigIn;
nSequence = nSequenceIn;
}
CTxIn::CTxIn(uint256 hashPrevTx, unsigned int nOut, CScript scriptSigIn, unsigned int nSequenceIn)
{
prevout = COutPoint(hashPrevTx, nOut);
scriptSig = scriptSigIn;
nSequence = nSequenceIn;
}
std::string CTxIn::ToString() const
{
std::string str;
str += "CTxIn(";
str += prevout.ToString();
if (prevout.IsNull())
str += strprintf(", coinbase %s", HexStr(scriptSig));
else
str += strprintf(", scriptSig=%s", scriptSig.ToString().substr(0,24));
if (nSequence != std::numeric_limits<unsigned int>::max())
str += strprintf(", nSequence=%u", nSequence);
str += ")";
return str;
}
void CTxIn::print() const
{
LogPrintf("%s\n", ToString());
}
CTxOut::CTxOut(int64_t nValueIn, CScript scriptPubKeyIn)
{
nValue = nValueIn;
scriptPubKey = scriptPubKeyIn;
}
uint256 CTxOut::GetHash() const
{
return SerializeHash(*this);
}
std::string CTxOut::ToString() const
{
return strprintf("CTxOut(nValue=%d.%08d, scriptPubKey=%s)", nValue / COIN, nValue % COIN, scriptPubKey.ToString().substr(0,30));
}
void CTxOut::print() const
{
LogPrintf("%s\n", ToString());
}
CFeeRate::CFeeRate(int64_t nFeePaid, size_t nSize)
{
if (nSize > 0)
nSatoshisPerK = nFeePaid*1000/nSize;
else
nSatoshisPerK = 0;
}
int64_t CFeeRate::GetFee(size_t nSize)
{
return nSatoshisPerK*nSize / 1000;
}
std::string CFeeRate::ToString() const
{
std::string result = FormatMoney(nSatoshisPerK) + " BTC/kB";
return result;
}
CMutableTransaction::CMutableTransaction() : nVersion(CTransaction::CURRENT_VERSION), nLockTime(0) {}
CMutableTransaction::CMutableTransaction(const CTransaction& tx) : nVersion(tx.nVersion), vin(tx.vin), vout(tx.vout), nLockTime(tx.nLockTime) {}
uint256 CMutableTransaction::GetHash() const
{
return SerializeHash(*this);
}
void CTransaction::UpdateHash() const
{
*const_cast<uint256*>(&hash) = SerializeHash(*this);
}
CTransaction::CTransaction() : hash(0), nVersion(CTransaction::CURRENT_VERSION), vin(), vout(), nLockTime(0) { }
CTransaction::CTransaction(const CMutableTransaction &tx) : nVersion(tx.nVersion), vin(tx.vin), vout(tx.vout), nLockTime(tx.nLockTime) {
UpdateHash();
}
CTransaction& CTransaction::operator=(const CTransaction &tx) {
*const_cast<int*>(&nVersion) = tx.nVersion;
*const_cast<std::vector<CTxIn>*>(&vin) = tx.vin;
*const_cast<std::vector<CTxOut>*>(&vout) = tx.vout;
*const_cast<unsigned int*>(&nLockTime) = tx.nLockTime;
*const_cast<uint256*>(&hash) = tx.hash;
return *this;
}
bool CTransaction::IsEquivalentTo(const CTransaction& tx) const
{
if (nVersion != tx.nVersion ||
nLockTime != tx.nLockTime ||
vin.size() != tx.vin.size() ||
vout != tx.vout)
return false;
for (unsigned int i = 0; i < vin.size(); i++)
{
if (vin[i].nSequence != tx.vin[i].nSequence ||
vin[i].prevout != tx.vin[i].prevout)
return false;
}
return true;
}
int64_t CTransaction::GetValueOut() const
{
int64_t nValueOut = 0;
BOOST_FOREACH(const CTxOut& txout, vout)
{
nValueOut += txout.nValue;
if (!MoneyRange(txout.nValue) || !MoneyRange(nValueOut))
throw std::runtime_error("CTransaction::GetValueOut() : value out of range");
}
return nValueOut;
}
double CTransaction::ComputePriority(double dPriorityInputs, unsigned int nTxSize) const
{
// In order to avoid disincentivizing cleaning up the UTXO set we don't count
// the constant overhead for each txin and up to 110 bytes of scriptSig (which
// is enough to cover a compressed pubkey p2sh redemption) for priority.
// Providing any more cleanup incentive than making additional inputs free would
// risk encouraging people to create junk outputs to redeem later.
if (nTxSize == 0)
nTxSize = ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION);
BOOST_FOREACH(const CTxIn& txin, vin)
{
unsigned int offset = 41U + std::min(110U, (unsigned int)txin.scriptSig.size());
if (nTxSize > offset)
nTxSize -= offset;
}
if (nTxSize == 0) return 0.0;
return dPriorityInputs / nTxSize;
}
std::string CTransaction::ToString() const
{
std::string str;
str += strprintf("CTransaction(hash=%s, ver=%d, vin.size=%u, vout.size=%u, nLockTime=%u)\n",
GetHash().ToString().substr(0,10),
nVersion,
vin.size(),
vout.size(),
nLockTime);
for (unsigned int i = 0; i < vin.size(); i++)
str += " " + vin[i].ToString() + "\n";
for (unsigned int i = 0; i < vout.size(); i++)
str += " " + vout[i].ToString() + "\n";
return str;
}
void CTransaction::print() const
{
LogPrintf("%s", ToString());
}
// Amount compression:
// * If the amount is 0, output 0
// * first, divide the amount (in base units) by the largest power of 10 possible; call the exponent e (e is max 9)
// * if e<9, the last digit of the resulting number cannot be 0; store it as d, and drop it (divide by 10)
// * call the result n
// * output 1 + 10*(9*n + d - 1) + e
// * if e==9, we only know the resulting number is not zero, so output 1 + 10*(n - 1) + 9
// (this is decodable, as d is in [1-9] and e is in [0-9])
uint64_t CTxOutCompressor::CompressAmount(uint64_t n)
{
if (n == 0)
return 0;
int e = 0;
while (((n % 10) == 0) && e < 9) {
n /= 10;
e++;
}
if (e < 9) {
int d = (n % 10);
assert(d >= 1 && d <= 9);
n /= 10;
return 1 + (n*9 + d - 1)*10 + e;
} else {
return 1 + (n - 1)*10 + 9;
}
}
uint64_t CTxOutCompressor::DecompressAmount(uint64_t x)
{
// x = 0 OR x = 1+10*(9*n + d - 1) + e OR x = 1+10*(n - 1) + 9
if (x == 0)
return 0;
x--;
// x = 10*(9*n + d - 1) + e
int e = x % 10;
x /= 10;
uint64_t n = 0;
if (e < 9) {
// x = 9*n + d - 1
int d = (x % 9) + 1;
x /= 9;
// x = n
n = x*10 + d;
} else {
n = x+1;
}
while (e) {
n *= 10;
e--;
}
return n;
}
uint256 CBlockHeader::GetHash() const
{
return Hash(BEGIN(nVersion), END(nNonce));
}
uint256 CBlock::BuildMerkleTree() const
{
vMerkleTree.clear();
BOOST_FOREACH(const CTransaction& tx, vtx)
vMerkleTree.push_back(tx.GetHash());
int j = 0;
for (int nSize = vtx.size(); nSize > 1; nSize = (nSize + 1) / 2)
{
for (int i = 0; i < nSize; i += 2)
{
int i2 = std::min(i+1, nSize-1);
vMerkleTree.push_back(Hash(BEGIN(vMerkleTree[j+i]), END(vMerkleTree[j+i]),
BEGIN(vMerkleTree[j+i2]), END(vMerkleTree[j+i2])));
}
j += nSize;
}
return (vMerkleTree.empty() ? 0 : vMerkleTree.back());
}
std::vector<uint256> CBlock::GetMerkleBranch(int nIndex) const
{
if (vMerkleTree.empty())
BuildMerkleTree();
std::vector<uint256> vMerkleBranch;
int j = 0;
for (int nSize = vtx.size(); nSize > 1; nSize = (nSize + 1) / 2)
{
int i = std::min(nIndex^1, nSize-1);
vMerkleBranch.push_back(vMerkleTree[j+i]);
nIndex >>= 1;
j += nSize;
}
return vMerkleBranch;
}
uint256 CBlock::CheckMerkleBranch(uint256 hash, const std::vector<uint256>& vMerkleBranch, int nIndex)
{
if (nIndex == -1)
return 0;
BOOST_FOREACH(const uint256& otherside, vMerkleBranch)
{
if (nIndex & 1)
hash = Hash(BEGIN(otherside), END(otherside), BEGIN(hash), END(hash));
else
hash = Hash(BEGIN(hash), END(hash), BEGIN(otherside), END(otherside));
nIndex >>= 1;
}
return hash;
}
void CBlock::print() const
{
LogPrintf("CBlock(hash=%s, ver=%d, hashPrevBlock=%s, hashMerkleRoot=%s, nTime=%u, nBits=%08x, nNonce=%u, vtx=%u)\n",
GetHash().ToString(),
nVersion,
hashPrevBlock.ToString(),
hashMerkleRoot.ToString(),
nTime, nBits, nNonce,
vtx.size());
for (unsigned int i = 0; i < vtx.size(); i++)
{
LogPrintf(" ");
vtx[i].print();
}
LogPrintf(" vMerkleTree: ");
for (unsigned int i = 0; i < vMerkleTree.size(); i++)
LogPrintf("%s ", vMerkleTree[i].ToString());
LogPrintf("\n");
}