Merge AuxPoW support from Namecore

Changes are as below:

* Wrap CBlockHeader::nVersion into a new class (CBlockVersion).  This allows to take care of interpreting the field into a base version, auxpow flag and the chain ID.
* Update getauxblock.py for new 'generate' RPC call.
* Add 'auxpow' to block JSON.
* Accept auxpow as PoW verification.
* Add unit tests for auxpow verification.
* Add check for memory-layout of CBlockVersion.
* Weaken auxpow chain ID checks for the testnet.
* Allow Params() to overrule when to check the auxpow chain ID and for legacy blocks.  Use this to disable the checks on testnet.
* Split the block header part that is used by auxpow and the "real" block header (that uses auxpow) to resolve the cyclic dependency between the two.
* Differentiate between uint256 and arith_uint256.
* Add missing lock in auxpow_tests.
* Fix REST header check for auxpow headers.
  * Those can be longer, thus take that into account.  Also perform the check actually on an auxpow header.
* Correctly set the coinbase for getauxblock results.
* Call IncrementExtraNonce in getauxblock so that the coinbase is actually initialised with the stuff it should be.  (BIP30 block height and COINBASE_FLAGS.)
* Implement getauxblock plus regression test.
* Turn auxpow test into FIXTURE test.
  * This allows using of the Params() calls.
* Move CMerkleTx code to auxpow.cpp.
  * Otherwise we get linker errors when building without wallet.
* Fix rebase with BIP66.
* Update the code to handle BIP66's nVersion=3.
* Enforce that auxpow parent blocks have no auxpow block version.
  * This is for compatibility with namecoind.  See also namecoin/namecoin-legacy#199.
* Move auxpow-related parameters to Consensus::Params.

.travis.yml

@@ -39,10 +39,10 @@ install:
 before_script:
   # Temporary workaround for https://github.com/bitcoin/bitcoin/issues/16368
   - for i in {1..4}; do echo "$(sleep 500)" ; done &
-  - set -o errexit; source ./ci/test/05_before_script.sh &> "/dev/null"
+  - set -o errexit; source ./ci/test/05_before_script.sh
 script:
   - export CONTINUE=1
-  - if [ $SECONDS -gt 1200 ]; then export CONTINUE=0; fi  # Likely the depends build took very long
+  - if [ $SECONDS -gt 1800 ]; then export CONTINUE=0; fi  # Likely the depends build took very long
   - if [ $TRAVIS_REPO_SLUG = "bitcoin/bitcoin" ]; then export CONTINUE=1; fi  # continue on repos with extended build time (90 minutes)
   - if [ $CONTINUE = "1" ]; then set -o errexit; source ./ci/test/06_script_a.sh; else set +o errexit; echo "$CACHE_ERR_MSG"; false; fi
   - if [[ $SECONDS -gt 50*60-$EXPECTED_TESTS_DURATION_IN_SECONDS ]]; then export CONTINUE=0; fi

src/Makefile.am

@@ -186,10 +186,12 @@ BITCOIN_CORE_H = \
   random.h \
   randomenv.h \
   reverse_iterator.h \
+  rpc/auxpow_miner.h \
   rpc/blockchain.h \
   rpc/client.h \
   rpc/mining.h \
   rpc/protocol.h \
+  rpc/rawtransaction.h \
   rpc/rawtransaction_util.h \
   rpc/register.h \
   rpc/request.h \
@@ -318,6 +320,7 @@ libbitcoin_server_a_SOURCES = \
   policy/settings.cpp \
   pow.cpp \
   rest.cpp \
+  rpc/auxpow_miner.cpp \
   rpc/blockchain.cpp \
   rpc/mining.cpp \
   rpc/misc.cpp \
@@ -590,8 +593,10 @@ if TARGET_WINDOWS
 dogecoin_daemon_sources += bitcoind-res.rc
 endif
 
+# FIXME: Remove SERVER once we have cleaned up getauxblock.
 dogecoin_bin_ldadd = \
   $(LIBBITCOIN_WALLET) \
+  $(LIBBITCOIN_SERVER) \
   $(LIBBITCOIN_COMMON) \
   $(LIBBITCOIN_UTIL) \
   $(LIBUNIVALUE) \

src/chain.cpp

@@ -11,7 +11,7 @@ bool ReadBlockHeaderFromDisk(CBlockHeader& block, const CBlockIndex* pindex, con
 
 /* Moved here from the header, because we need auxpow and the logic
    becomes more involved.  */
-CBlockHeader CBlockIndex::GetBlockHeader(const Consensus::Params& consensusParams, bool fCheckPOW) const
+CBlockHeader CBlockIndex::GetBlockHeader(const Consensus::Params& consensusParams, const bool fCheckPOW) const
 {
     CBlockHeader block;
 

src/chain.h

@@ -191,7 +191,7 @@ class CBlockIndex
     {
     }
 
-    explicit CBlockIndex(const CBlockHeader& block)
+    explicit CBlockIndex(const CPureBlockHeader& block)
         : nVersion{block.nVersion},
           hashMerkleRoot{block.hashMerkleRoot},
           nTime{block.nTime},
@@ -218,7 +218,7 @@ class CBlockIndex
         return ret;
     }
 
-    CBlockHeader GetBlockHeader(const Consensus::Params& consensusParams, bool fCheckPOW = true) const;
+    CBlockHeader GetBlockHeader(const Consensus::Params& consensusParams, const bool fCheckPOW = true) const;
 
     uint256 GetBlockHash() const
     {

src/chainparams.h

@@ -91,6 +91,9 @@ class CChainParams
     const std::vector<SeedSpec6>& FixedSeeds() const { return vFixedSeeds; }
     const CCheckpointData& Checkpoints() const { return checkpointData; }
     const ChainTxData& TxData() const { return chainTxData; }
+
+    void UpdateVersionBitsParameters(Consensus::DeploymentPos d, int64_t nStartTime, int64_t nTimeout);
+
 protected:
     CChainParams() {}
 

src/init.cpp

@@ -39,6 +39,7 @@
 #include <policy/settings.h>
 #include <primitives/pureheader.h>
 #include <protocol.h>
+#include <rpc/auxpow_miner.h>
 #include <rpc/blockchain.h>
 #include <rpc/register.h>
 #include <rpc/server.h>
@@ -600,7 +601,7 @@ void SetupServerArgs(NodeContext& node)
 
 std::string LicenseInfo()
 {
-    const std::string URL_SOURCE_CODE = "<https://github.com/bitcoin/bitcoin>";
+    const std::string URL_SOURCE_CODE = "<https://github.com/dogecoin/dogecoin>";
 
     return CopyrightHolders(strprintf(_("Copyright (C) %i-%i").translated, 2009, COPYRIGHT_YEAR) + " ") + "\n" +
            "\n" +

src/miner.h

@@ -132,10 +132,12 @@ class BlockAssembler
     // Configuration parameters for the block size
     bool fIncludeWitness;
     unsigned int nBlockMaxWeight;
+    bool fNeedSizeAccounting;
     CFeeRate blockMinFeeRate;
 
     // Information on the current status of the block
     uint64_t nBlockWeight;
+    uint64_t nBlockSize;
     uint64_t nBlockTx;
     uint64_t nBlockSigOpsCost;
     CAmount nFees;
@@ -200,6 +202,7 @@ class BlockAssembler
 /** Modify the extranonce in a block */
 void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned int& nExtraNonce);
 int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev);
+bool ProcessBlockFound(const CBlock* pblock, const CChainParams& chainParams);
 
 /** Update an old GenerateCoinbaseCommitment from CreateNewBlock after the block txs have changed */
 void RegenerateCommitments(CBlock& block);

src/pow.cpp

@@ -5,10 +5,12 @@
 
 #include <pow.h>
 
+#include <auxpow.h>
 #include <arith_uint256.h>
 #include <chain.h>
 #include <dogecoin.h>
 #include <primitives/block.h>
+#include <util/system.h>
 #include <uint256.h>
 
 unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
@@ -114,3 +116,41 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params&
 
     return true;
 }
+
+bool CheckAuxPowProofOfWork(const CBlockHeader& block, const Consensus::Params& params)
+{
+    /* Except for legacy blocks with full version 1, ensure that
+       the chain ID is correct.  Legacy blocks are not allowed since
+       the merge-mining start, which is checked in AcceptBlockHeader
+       where the height is known.  */
+    if (!block.IsLegacy() && params.fStrictChainId
+        && block.GetChainId() != params.nAuxpowChainId)
+        return error("%s : block does not have our chain ID"
+                     " (got %d, expected %d, full nVersion %d)",
+                     __func__, block.GetChainId(),
+                     params.nAuxpowChainId, block.nVersion);
+
+    /* If there is no auxpow, just check the block hash.  */
+    if (!block.auxpow) {
+        if (block.IsAuxpow())
+            return error("%s : no auxpow on block with auxpow version",
+                         __func__);
+
+        if (!CheckProofOfWork(block.GetPoWHash(), block.nBits, params))
+            return error("%s : non-AUX proof of work failed", __func__);
+
+        return true;
+    }
+
+    /* We have auxpow.  Check it.  */
+
+    if (!block.IsAuxpow())
+        return error("%s : auxpow on block with non-auxpow version", __func__);
+
+    if (!block.auxpow->check(block.GetHash(), block.GetChainId(), params))
+        return error("%s : AUX POW is not valid", __func__);
+    if (!CheckProofOfWork(block.auxpow->getParentBlockPoWHash(), block.nBits, params))
+        return error("%s : AUX proof of work failed", __func__);
+
+    return true;
+}

src/pow.h

@@ -20,4 +20,12 @@ unsigned int CalculateNextWorkRequired(const CBlockIndex* pindexLast, int64_t nF
 /** Check whether a block hash satisfies the proof-of-work requirement specified by nBits */
 bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params&);
 
+/**
+ * Check proof-of-work of a block header, taking auxpow into account.
+ * @param block The block header.
+ * @param params Consensus parameters.
+ * @return True iff the PoW is correct.
+ */
+bool CheckAuxPowProofOfWork(const CBlockHeader& block, const Consensus::Params& params);
+
 #endif // BITCOIN_POW_H

src/protocol.cpp

@@ -134,7 +134,6 @@ bool CMessageHeader::IsCommandValid() const
     return true;
 }
 
-
 ServiceFlags GetDesirableServiceFlags(ServiceFlags services) {
     if ((services & NODE_NETWORK_LIMITED) && g_initial_block_download_completed) {
         return ServiceFlags(NODE_NETWORK_LIMITED | NODE_WITNESS);

src/qt/test/wallettests.cpp

@@ -133,7 +133,7 @@ void BumpFee(TransactionView& view, const uint256& txid, bool expectDisabled, st
 //     QT_QPA_PLATFORM=cocoa   src/qt/test/test_bitcoin-qt  # macOS
 void TestGUI(interfaces::Node& node)
 {
-    // Set up wallet and chain with 105 blocks (5 mature blocks for spending).
+    // Set up wallet and chain with 245 blocks (5 mature blocks for spending).
     TestChain240Setup test;
     for (int i = 0; i < 5; ++i) {
         test.CreateAndProcessBlock({}, GetScriptForRawPubKey(test.coinbaseKey.GetPubKey()));

src/rpc/blockchain.cpp

@@ -22,6 +22,7 @@
 #include <policy/policy.h>
 #include <policy/rbf.h>
 #include <primitives/transaction.h>
+#include <rpc/rawtransaction.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
 #include <script/descriptor.h>
@@ -116,6 +117,43 @@ static int ComputeNextBlockAndDepth(const CBlockIndex* tip, const CBlockIndex* b
     return blockindex == tip ? 1 : -1;
 }
 
+
+UniValue AuxpowToJSON(const CAuxPow& auxpow)
+{
+    UniValue result(UniValue::VOBJ);
+
+    {
+        UniValue tx(UniValue::VOBJ);
+        tx.pushKV("hex", EncodeHexTx(*auxpow.coinbaseTx));
+        TxToJSON(*auxpow.coinbaseTx, auxpow.parentBlock.GetHash(), tx);
+        result.pushKV("tx", tx);
+    }
+
+    // FIXME: We have a compatibility issue where the "index" field is no longer available in 1.21
+    result.pushKV("chainindex", auxpow.nChainIndex);
+
+    {
+        UniValue branch(UniValue::VARR);
+        for (const auto& node : auxpow.vMerkleBranch)
+            branch.push_back(node.GetHex());
+        result.pushKV("merklebranch", branch);
+    }
+
+    {
+        UniValue branch(UniValue::VARR);
+        for (const auto& node : auxpow.vChainMerkleBranch)
+            branch.push_back(node.GetHex());
+        result.pushKV("chainmerklebranch", branch);
+    }
+
+    CDataStream ssParent(SER_NETWORK, PROTOCOL_VERSION);
+    ssParent << auxpow.parentBlock;
+    const std::string strHex = HexStr(ssParent);
+    result.pushKV("parentblock", strHex);
+
+    return result;
+}
+
 UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex)
 {
     // Serialize passed information without accessing chain state of the active chain!
@@ -183,6 +221,9 @@ UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIn
     result.pushKV("chainwork", blockindex->nChainWork.GetHex());
     result.pushKV("nTx", (uint64_t)blockindex->nTx);
 
+    if (block.auxpow)
+        result.pushKV("auxpow", AuxpowToJSON(*block.auxpow));
+
     if (blockindex->pprev)
         result.pushKV("previousblockhash", blockindex->pprev->GetBlockHash().GetHex());
     if (pnext)