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// Copyright (c) 2011 Vince Durham
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.
#include "script.h"
#include "auxpow.h"
#include "init.h"
using namespace std;
using namespace boost;
unsigned char pchMergedMiningHeader[] = { 0xfa, 0xbe, 'm', 'm' } ;
void RemoveMergedMiningHeader(vector<unsigned char>& vchAux)
{
if (vchAux.begin() != std::search(vchAux.begin(), vchAux.end(), UBEGIN(pchMergedMiningHeader), UEND(pchMergedMiningHeader)))
throw runtime_error("merged mining aux too short");
vchAux.erase(vchAux.begin(), vchAux.begin() + sizeof(pchMergedMiningHeader));
}
bool CAuxPow::Check(uint256 hashAuxBlock, int nChainID)
{
if (nIndex != 0)
return error("AuxPow is not a generate");
if (!TestNet() && parentBlockHeader.GetChainID() == nChainID)
return error("Aux POW parent has our chain ID");
if (vChainMerkleBranch.size() > 30)
return error("Aux POW chain merkle branch too long");
// Check that the chain merkle root is in the coinbase
uint256 nRootHash = CBlock::CheckMerkleBranch(hashAuxBlock, vChainMerkleBranch, nChainIndex);
vector<unsigned char> vchRootHash(nRootHash.begin(), nRootHash.end());
std::reverse(vchRootHash.begin(), vchRootHash.end()); // correct endian
// Check that we are in the parent block merkle tree
if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != parentBlockHeader.hashMerkleRoot)
return error("Aux POW merkle root incorrect");
const CScript script = vin[0].scriptSig;
// Check that the same work is not submitted twice to our chain.
//
CScript::const_iterator pcHead =
std::search(script.begin(), script.end(), UBEGIN(pchMergedMiningHeader), UEND(pchMergedMiningHeader));
CScript::const_iterator pc =
std::search(script.begin(), script.end(), vchRootHash.begin(), vchRootHash.end());
if (pcHead == script.end())
return error("MergedMiningHeader missing from parent coinbase");
if (pc == script.end())
return error("Aux POW missing chain merkle root in parent coinbase");
// Enforce only one chain merkle root by checking that a single instance of the merged
// mining header exists just before.
if (script.end() != std::search(pcHead + 1, script.end(), UBEGIN(pchMergedMiningHeader), UEND(pchMergedMiningHeader)))
return error("Multiple merged mining headers in coinbase");
if (pcHead + sizeof(pchMergedMiningHeader) != pc)
return error("Merged mining header is not just before chain merkle root");
// Ensure we are at a deterministic point in the merkle leaves by hashing
// a nonce and our chain ID and comparing to the index.
pc += vchRootHash.size();
if (script.end() - pc < 8)
return error("Aux POW missing chain merkle tree size and nonce in parent coinbase");
int nSize;
memcpy(&nSize, &pc[0], 4);
if (nSize != (1 << vChainMerkleBranch.size()))
return error("Aux POW merkle branch size does not match parent coinbase");
int nNonce;
memcpy(&nNonce, &pc[4], 4);
// Choose a pseudo-random slot in the chain merkle tree
// but have it be fixed for a size/nonce/chain combination.
//
// This prevents the same work from being used twice for the
// same chain while reducing the chance that two chains clash
// for the same slot.
unsigned int rand = nNonce;
rand = rand * 1103515245 + 12345;
rand += nChainID;
rand = rand * 1103515245 + 12345;
if (nChainIndex != (rand % nSize))
return error("Aux POW wrong index");
return true;
}
CScript MakeCoinbaseWithAux(unsigned int nHeight, unsigned int nExtraNonce, vector<unsigned char>& vchAux)
{
vector<unsigned char> vchAuxWithHeader(UBEGIN(pchMergedMiningHeader), UEND(pchMergedMiningHeader));
vchAuxWithHeader.insert(vchAuxWithHeader.end(), vchAux.begin(), vchAux.end());
CScript script = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
// Push OP_2 just in case we want versioning later
script = script << OP_2 << vchAuxWithHeader;
return script;
}
void IncrementExtraNonceWithAux(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce, vector<unsigned char>& vchAux)
{
// Update nExtraNonce
static uint256 hashPrevBlock;
if (hashPrevBlock != pblock->hashPrevBlock)
{
nExtraNonce = 0;
hashPrevBlock = pblock->hashPrevBlock;
}
++nExtraNonce;
unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
pblock->vtx[0].vin[0].scriptSig = MakeCoinbaseWithAux(nHeight, nExtraNonce, vchAux);
pblock->hashMerkleRoot = pblock->BuildMerkleTree();
}
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