Create auxpow.cpp

src/auxpow.cpp

@@ -0,0 +1,137 @@
+// 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");
+
+    if (pcHead != script.end())
+    {
+        // 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");
+    }
+    else
+    {
+        // For backward compatibility.
+        // Enforce only one chain merkle root by checking that it starts early in the coinbase.
+        // 8-12 bytes are enough to encode extraNonce and nBits.
+        if (pc - script.begin() > 20)
+            return error("Aux POW chain merkle root must start in the first 20 bytes of the parent coinbase");
+    }
+
+
+    // 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();
+}
+
+