Implement and enforce CbTx with correct block height and deprecate BIP34

src/Makefile.am

@@ -110,6 +110,7 @@ BITCOIN_CORE_H = \
   evo/specialtx.h \
   evo/providertx.h \
   evo/deterministicmns.h \
+  evo/cbtx.h \
   privatesend.h \
   privatesend-client.h \
   privatesend-server.h \
@@ -224,6 +225,7 @@ libdash_server_a_SOURCES = \
   evo/specialtx.cpp \
   evo/providertx.cpp \
   evo/deterministicmns.cpp \
+  evo/cbtx.cpp \
   httprpc.cpp \
   httpserver.cpp \
   init.cpp \

src/evo/cbtx.cpp

@@ -0,0 +1,47 @@
+// Copyright (c) 2017 The Dash Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "cbtx.h"
+#include "specialtx.h"
+#include "deterministicmns.h"
+
+#include "validation.h"
+#include "univalue.h"
+
+bool CheckCbTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
+{
+    AssertLockHeld(cs_main);
+
+    if (!tx.IsCoinBase())
+        return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-invalid");
+
+    CCbTx cbTx;
+    if (!GetTxPayload(tx, cbTx))
+        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+
+    if (cbTx.nVersion > CCbTx::CURRENT_VERSION)
+        return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-version");
+
+    if (pindexPrev) {
+        if (pindexPrev->nHeight + 1 != cbTx.nHeight)
+            return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-height");
+    }
+
+    return true;
+}
+
+std::string CCbTx::ToString() const
+{
+    return strprintf("CCbTx(nHeight=%d, nVersion=%d, merkleRootMNList=%s)",
+        nVersion, nHeight, merkleRootMNList.ToString());
+}
+
+void CCbTx::ToJson(UniValue& obj) const
+{
+    obj.clear();
+    obj.setObject();
+    obj.push_back(Pair("version", (int)nVersion));
+    obj.push_back(Pair("height", (int)nHeight));
+    obj.push_back(Pair("merkleRootMNList", merkleRootMNList.ToString()));
+}

src/evo/cbtx.h

@@ -0,0 +1,42 @@
+// Copyright (c) 2017 The Dash Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DASH_CBTX_H
+#define DASH_CBTX_H
+
+#include "primitives/transaction.h"
+#include "consensus/validation.h"
+
+class CBlockIndex;
+class UniValue;
+
+// coinbase transaction
+class CCbTx
+{
+public:
+    static const uint16_t CURRENT_VERSION = 1;
+
+public:
+    uint16_t nVersion{CURRENT_VERSION};
+    int32_t nHeight{0};
+    uint256 merkleRootMNList;
+
+public:
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action)
+    {
+        READWRITE(nVersion);
+        READWRITE(nHeight);
+        READWRITE(merkleRootMNList);
+    }
+
+    std::string ToString() const;
+    void ToJson(UniValue& obj) const;
+};
+
+bool CheckCbTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state);
+
+#endif//DASH_CBTX_H

src/evo/specialtx.cpp

@@ -12,6 +12,7 @@
 
 #include "specialtx.h"
 #include "deterministicmns.h"
+#include "cbtx.h"
 
 bool CheckSpecialTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
@@ -33,6 +34,8 @@ bool CheckSpecialTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CVali
             return CheckProUpRegTx(tx, pindexPrev, state);
         case TRANSACTION_PROVIDER_UPDATE_REVOKE:
             return CheckProUpRevTx(tx, pindexPrev, state);
+        case TRANSACTION_COINBASE:
+            return CheckCbTx(tx, pindexPrev, state);
     }
 
     return state.DoS(10, false, REJECT_INVALID, "bad-tx-type");
@@ -49,6 +52,8 @@ bool ProcessSpecialTx(const CTransaction& tx, const CBlockIndex* pindex, CValida
         case TRANSACTION_PROVIDER_UPDATE_REGISTRAR:
         case TRANSACTION_PROVIDER_UPDATE_REVOKE:
             return true; // handled in batches per block
+        case TRANSACTION_COINBASE:
+            return true; // nothing to do
     }
 
     return state.DoS(100, false, REJECT_INVALID, "bad-tx-type");
@@ -65,6 +70,8 @@ bool UndoSpecialTx(const CTransaction& tx, const CBlockIndex* pindex)
         case TRANSACTION_PROVIDER_UPDATE_REGISTRAR:
         case TRANSACTION_PROVIDER_UPDATE_REVOKE:
             return true; // handled in batches per block
+        case TRANSACTION_COINBASE:
+            return true; // nothing to do
     }
 
     return false;

src/miner.cpp

@@ -28,6 +28,9 @@
 #include "masternode-sync.h"
 #include "validationinterface.h"
 
+#include "evo/specialtx.h"
+#include "evo/cbtx.h"
+
 #include <algorithm>
 #include <boost/thread.hpp>
 #include <boost/tuple/tuple.hpp>
@@ -126,6 +129,9 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
     pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 
     LOCK2(cs_main, mempool.cs);
+
+    bool fDIP0003Active_context = VersionBitsState(chainActive.Tip(), chainparams.GetConsensus(), Consensus::DEPLOYMENT_DIP0003, versionbitscache) == THRESHOLD_ACTIVE;
+
     CBlockIndex* pindexPrev = chainActive.Tip();
     nHeight = pindexPrev->nHeight + 1;
 
@@ -166,7 +172,19 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
 
     // Compute regular coinbase transaction.
     coinbaseTx.vout[0].nValue = blockReward;
-    coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
+
+    if (!fDIP0003Active_context) {
+        coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
+    } else {
+        coinbaseTx.vin[0].scriptSig = CScript() << OP_RETURN;
+
+        coinbaseTx.nVersion = 3;
+        coinbaseTx.nType = TRANSACTION_COINBASE;
+
+        CCbTx cbTx;
+        cbTx.nHeight = nHeight;
+        SetTxPayload(coinbaseTx, cbTx);
+    }
 
     // Update coinbase transaction with additional info about masternode and governance payments,
     // get some info back to pass to getblocktemplate

src/primitives/transaction.h

@@ -18,6 +18,7 @@ enum {
     TRANSACTION_PROVIDER_UPDATE_SERVICE = 2,
     TRANSACTION_PROVIDER_UPDATE_REGISTRAR = 3,
     TRANSACTION_PROVIDER_UPDATE_REVOKE = 4,
+    TRANSACTION_COINBASE = 5,
 };
 
 /** An outpoint - a combination of a transaction hash and an index n into its vout */

src/rpc/rawtransaction.cpp

@@ -31,6 +31,7 @@
 
 #include "evo/specialtx.h"
 #include "evo/providertx.h"
+#include "evo/cbtx.h"
 
 #include <stdint.h>
 
@@ -158,6 +159,13 @@ void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry)
             proTx.ToJson(proTxObj);
             entry.push_back(Pair("proUpRevTx", proTxObj));
         }
+    } else if (tx.nType == TRANSACTION_COINBASE) {
+        CCbTx cbTx;
+        if (GetTxPayload(tx, cbTx)) {
+            UniValue proTxObj;
+            cbTx.ToJson(proTxObj);
+            entry.push_back(Pair("cbTx", proTxObj));
+        }
     }
 
     if (!hashBlock.IsNull()) {

src/validation.cpp

@@ -45,6 +45,7 @@
 #include "evo/specialtx.h"
 #include "evo/providertx.h"
 #include "evo/deterministicmns.h"
+#include "evo/cbtx.h"
 
 #include <atomic>
 #include <sstream>
@@ -550,7 +551,12 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state, bool fChe
 
     if (tx.IsCoinBase())
     {
-        if (tx.vin[0].scriptSig.size() < 2 || tx.vin[0].scriptSig.size() > 100)
+        int minCbSize = 2;
+        if (tx.nType == TRANSACTION_COINBASE) {
+            // With the introduction of CbTx, coinbase scripts are not required anymore to hold a valid block height
+            minCbSize = 1;
+        }
+        if (tx.vin[0].scriptSig.size() < minCbSize || tx.vin[0].scriptSig.size() > 100)
             return state.DoS(100, false, REJECT_INVALID, "bad-cb-length");
     }
     else
@@ -576,10 +582,11 @@ bool ContextualCheckTransaction(const CTransaction& tx, CValidationState &state,
                 tx.nType != TRANSACTION_PROVIDER_REGISTER &&
                 tx.nType != TRANSACTION_PROVIDER_UPDATE_SERVICE &&
                 tx.nType != TRANSACTION_PROVIDER_UPDATE_REGISTRAR &&
-                tx.nType != TRANSACTION_PROVIDER_UPDATE_REVOKE) {
+                tx.nType != TRANSACTION_PROVIDER_UPDATE_REVOKE &&
+                tx.nType != TRANSACTION_COINBASE) {
                 return state.DoS(100, false, REJECT_INVALID, "bad-txns-type");
             }
-            if (tx.IsCoinBase() && tx.nType != TRANSACTION_NORMAL)
+            if (tx.IsCoinBase() && tx.nType != TRANSACTION_COINBASE)
                 return state.DoS(100, false, REJECT_INVALID, "bad-txns-cb-type");
         } else if (tx.nType != TRANSACTION_NORMAL) {
             return state.DoS(100, false, REJECT_INVALID, "bad-txns-type");
@@ -3513,6 +3520,7 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Co
                               : block.GetBlockTime();
 
     bool fDIP0001Active_context = nHeight >= Params().GetConsensus().DIP0001Height;
+    bool fDIP0003Active_context = VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_DIP0003, versionbitscache) == THRESHOLD_ACTIVE;
 
     // Size limits
     unsigned int nMaxBlockSize = MaxBlockSize(fDIP0001Active_context);
@@ -3537,7 +3545,9 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Co
         return state.DoS(10, false, REJECT_INVALID, "bad-blk-sigops", false, "out-of-bounds SigOpCount");
 
     // Enforce rule that the coinbase starts with serialized block height
-    if (nHeight >= consensusParams.BIP34Height)
+    // After DIP3/DIP4 activation, we don't enforce the height in the input script anymore.
+    // The CbTx special transaction payload will then contain the height, which is checked in CheckCbTx
+    if (nHeight >= consensusParams.BIP34Height && !fDIP0003Active_context)
     {
         CScript expect = CScript() << nHeight;
         if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() ||
@@ -3546,6 +3556,12 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Co
         }
     }
 
+    if (fDIP0003Active_context) {
+        if (block.vtx[0]->nType != TRANSACTION_COINBASE) {
+            return state.DoS(100, false, REJECT_INVALID, "bad-cb-type", false, "coinbase is not a CbTx");
+        }
+    }
+
     return true;
 }