1 files changed, 53 insertions, 39 deletions

diff --git a/src/main.cpp b/src/main.cpp
index a6b717d57f..4f4926eb40 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -56,6 +56,7 @@ bool fHavePruned = false;
 bool fPruneMode = false;
 bool fIsBareMultisigStd = true;
 bool fCheckBlockIndex = false;
+bool fCheckpointsEnabled = true;
 unsigned int nCoinCacheSize = 5000;
 uint64_t nPruneTarget = 0;
 
@@ -142,8 +143,9 @@ namespace {
     uint32_t nBlockSequenceId = 1;
 
     /**
-     * Sources of received blocks, to be able to send them reject messages or ban
-     * them, if processing happens afterwards. Protected by cs_main.
+     * Sources of received blocks, saved to be able to send them reject
+     * messages or ban them when processing happens afterwards. Protected by
+     * cs_main.
      */
     map<uint256, NodeId> mapBlockSource;
 
@@ -389,7 +391,7 @@ void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vector<CBl
     }
 
     // If the peer reorganized, our previous pindexLastCommonBlock may not be an ancestor
-    // of their current tip anymore. Go back enough to fix that.
+    // of its current tip anymore. Go back enough to fix that.
     state->pindexLastCommonBlock = LastCommonAncestor(state->pindexLastCommonBlock, state->pindexBestKnownBlock);
     if (state->pindexLastCommonBlock == state->pindexBestKnownBlock)
         return;
@@ -941,7 +943,7 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
 
         // do all inputs exist?
         // Note that this does not check for the presence of actual outputs (see the next check for that),
-        // only helps filling in pfMissingInputs (to determine missing vs spent).
+        // and only helps with filling in pfMissingInputs (to determine missing vs spent).
         BOOST_FOREACH(const CTxIn txin, tx.vin) {
             if (!view.HaveCoins(txin.prevout.hash)) {
                 if (pfMissingInputs)
@@ -1204,8 +1206,11 @@ CAmount GetBlockValue(int nHeight, const CAmount& nFees)
 
 bool IsInitialBlockDownload()
 {
+    const CChainParams& chainParams = Params();
     LOCK(cs_main);
-    if (fImporting || fReindex || chainActive.Height() < Checkpoints::GetTotalBlocksEstimate())
+    if (fImporting || fReindex)
+        return true;
+    if (fCheckpointsEnabled && chainActive.Height() < Checkpoints::GetTotalBlocksEstimate(chainParams.Checkpoints()))
         return true;
     static bool lockIBDState = false;
     if (lockIBDState)
@@ -1277,8 +1282,8 @@ void CheckForkWarningConditionsOnNewFork(CBlockIndex* pindexNewForkTip)
         pfork = pfork->pprev;
     }
 
-    // We define a condition which we should warn the user about as a fork of at least 7 blocks
-    // who's tip is within 72 blocks (+/- 12 hours if no one mines it) of ours
+    // We define a condition where we should warn the user about as a fork of at least 7 blocks
+    // with a tip within 72 blocks (+/- 12 hours if no one mines it) of ours
     // We use 7 blocks rather arbitrarily as it represents just under 10% of sustained network
     // hash rate operating on the fork.
     // or a chain that is entirely longer than ours and invalid (note that this should be detected by both)
@@ -1709,7 +1714,7 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
         return true;
     }
 
-    bool fScriptChecks = pindex->nHeight >= Checkpoints::GetTotalBlocksEstimate();
+    bool fScriptChecks = (!fCheckpointsEnabled || pindex->nHeight >= Checkpoints::GetTotalBlocksEstimate(chainparams.Checkpoints()));
 
     // Do not allow blocks that contain transactions which 'overwrite' older transactions,
     // unless those are already completely spent.
@@ -1719,9 +1724,9 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
     // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
     // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
     // already refuses previously-known transaction ids entirely.
-    // This rule was originally applied all blocks whose timestamp was after March 15, 2012, 0:00 UTC.
+    // This rule was originally applied to all blocks with a timestamp after March 15, 2012, 0:00 UTC.
     // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the
-    // two in the chain that violate it. This prevents exploiting the issue against nodes in their
+    // two in the chain that violate it. This prevents exploiting the issue against nodes during their
     // initial block download.
     bool fEnforceBIP30 = (!pindex->phashBlock) || // Enforce on CreateNewBlock invocations which don't have a hash.
                           !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256S("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) ||
@@ -1954,6 +1959,7 @@ void PruneAndFlush() {
 
 /** Update chainActive and related internal data structures. */
 void static UpdateTip(CBlockIndex *pindexNew) {
+    const CChainParams& chainParams = Params();
     chainActive.SetTip(pindexNew);
 
     // New best block
@@ -1963,7 +1969,7 @@ void static UpdateTip(CBlockIndex *pindexNew) {
     LogPrintf("%s: new best=%s  height=%d  log2_work=%.8g  tx=%lu  date=%s progress=%f  cache=%u\n", __func__,
       chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(), log(chainActive.Tip()->nChainWork.getdouble())/log(2.0), (unsigned long)chainActive.Tip()->nChainTx,
       DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
-      Checkpoints::GuessVerificationProgress(chainActive.Tip()), (unsigned int)pcoinsTip->GetCacheSize());
+      Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), chainActive.Tip()), (unsigned int)pcoinsTip->GetCacheSize());
 
     cvBlockChange.notify_all();
 
@@ -1984,7 +1990,7 @@ void static UpdateTip(CBlockIndex *pindexNew) {
         if (nUpgraded > 100/2)
         {
             // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
-            strMiscWarning = _("Warning: This version is obsolete, upgrade required!");
+            strMiscWarning = _("Warning: This version is obsolete; upgrade required!");
             CAlert::Notify(strMiscWarning, true);
             fWarned = true;
         }
@@ -2247,6 +2253,7 @@ static bool ActivateBestChainStep(CValidationState &state, CBlockIndex *pindexMo
 bool ActivateBestChain(CValidationState &state, CBlock *pblock) {
     CBlockIndex *pindexNewTip = NULL;
     CBlockIndex *pindexMostWork = NULL;
+    const CChainParams& chainParams = Params();
     do {
         boost::this_thread::interruption_point();
 
@@ -2271,7 +2278,9 @@ bool ActivateBestChain(CValidationState &state, CBlock *pblock) {
         if (!fInitialDownload) {
             uint256 hashNewTip = pindexNewTip->GetBlockHash();
             // Relay inventory, but don't relay old inventory during initial block download.
-            int nBlockEstimate = Checkpoints::GetTotalBlocksEstimate();
+            int nBlockEstimate = 0;
+            if (fCheckpointsEnabled)
+                nBlockEstimate = Checkpoints::GetTotalBlocksEstimate(chainParams.Checkpoints());
             // Don't relay blocks if pruning -- could cause a peer to try to download, resulting
             // in a stalled download if the block file is pruned before the request.
             if (nLocalServices & NODE_NETWORK) {
@@ -2315,7 +2324,7 @@ bool InvalidateBlock(CValidationState& state, CBlockIndex *pindex) {
     }
 
     // The resulting new best tip may not be in setBlockIndexCandidates anymore, so
-    // add them again.
+    // add it again.
     BlockMap::iterator it = mapBlockIndex.begin();
     while (it != mapBlockIndex.end()) {
         if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && !setBlockIndexCandidates.value_comp()(it->second, chainActive.Tip())) {
@@ -2601,7 +2610,8 @@ bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bo
 
 bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex * const pindexPrev)
 {
-    const Consensus::Params& consensusParams = Params().GetConsensus();
+    const CChainParams& chainParams = Params();
+    const Consensus::Params& consensusParams = chainParams.GetConsensus();
     uint256 hash = block.GetHash();
     if (hash == consensusParams.hashGenesisBlock)
         return true;
@@ -2611,7 +2621,7 @@ bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& sta
     int nHeight = pindexPrev->nHeight+1;
 
     // Check proof of work
-    if (block.nBits != GetNextWorkRequired(pindexPrev, &block, Params().GetConsensus()))
+    if (block.nBits != GetNextWorkRequired(pindexPrev, &block, consensusParams))
         return state.DoS(100, error("%s: incorrect proof of work", __func__),
                          REJECT_INVALID, "bad-diffbits");
 
@@ -2620,25 +2630,28 @@ bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& sta
         return state.Invalid(error("%s: block's timestamp is too early", __func__),
                              REJECT_INVALID, "time-too-old");
 
-    // Check that the block chain matches the known block chain up to a checkpoint
-    if (!Checkpoints::CheckBlock(nHeight, hash))
-        return state.DoS(100, error("%s: rejected by checkpoint lock-in at %d", __func__, nHeight),
-                         REJECT_CHECKPOINT, "checkpoint mismatch");
+    if(fCheckpointsEnabled)
+    {
+        // Check that the block chain matches the known block chain up to a checkpoint
+        if (!Checkpoints::CheckBlock(chainParams.Checkpoints(), nHeight, hash))
+            return state.DoS(100, error("%s: rejected by checkpoint lock-in at %d", __func__, nHeight),
+                             REJECT_CHECKPOINT, "checkpoint mismatch");
 
-    // Don't accept any forks from the main chain prior to last checkpoint
-    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint();
-    if (pcheckpoint && nHeight < pcheckpoint->nHeight)
-        return state.DoS(100, error("%s: forked chain older than last checkpoint (height %d)", __func__, nHeight));
+        // Don't accept any forks from the main chain prior to last checkpoint
+        CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(chainParams.Checkpoints());
+        if (pcheckpoint && nHeight < pcheckpoint->nHeight)
+            return state.DoS(100, error("%s: forked chain older than last checkpoint (height %d)", __func__, nHeight));
+    }
 
     // Reject block.nVersion=1 blocks when 95% (75% on testnet) of the network has upgraded:
-    if (block.nVersion < 2 && IsSuperMajority(2, pindexPrev, Params().RejectBlockOutdatedMajority()))
+    if (block.nVersion < 2 && IsSuperMajority(2, pindexPrev, consensusParams.nMajorityRejectBlockOutdated))
     {
         return state.Invalid(error("%s: rejected nVersion=1 block", __func__),
                              REJECT_OBSOLETE, "bad-version");
     }
 
     // Reject block.nVersion=2 blocks when 95% (75% on testnet) of the network has upgraded:
-    if (block.nVersion < 3 && IsSuperMajority(3, pindexPrev, Params().RejectBlockOutdatedMajority()))
+    if (block.nVersion < 3 && IsSuperMajority(3, pindexPrev, consensusParams.nMajorityRejectBlockOutdated))
     {
         return state.Invalid(error("%s : rejected nVersion=2 block", __func__),
                              REJECT_OBSOLETE, "bad-version");
@@ -3025,6 +3038,7 @@ CBlockIndex * InsertBlockIndex(uint256 hash)
 
 bool static LoadBlockIndexDB()
 {
+    const CChainParams& chainparams = Params();
     if (!pblocktree->LoadBlockIndexGuts())
         return false;
 
@@ -3127,7 +3141,7 @@ bool static LoadBlockIndexDB()
     LogPrintf("%s: hashBestChain=%s height=%d date=%s progress=%f\n", __func__,
         chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
         DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
-        Checkpoints::GuessVerificationProgress(chainActive.Tip()));
+        Checkpoints::GuessVerificationProgress(chainparams.Checkpoints(), chainActive.Tip()));
 
     return true;
 }
@@ -3733,7 +3747,7 @@ void static ProcessGetData(CNode* pfrom)
                             pfrom->PushMessage("merkleblock", merkleBlock);
                             // CMerkleBlock just contains hashes, so also push any transactions in the block the client did not see
                             // This avoids hurting performance by pointlessly requiring a round-trip
-                            // Note that there is currently no way for a node to request any single transactions we didnt send here -
+                            // Note that there is currently no way for a node to request any single transactions we didn't send here -
                             // they must either disconnect and retry or request the full block.
                             // Thus, the protocol spec specified allows for us to provide duplicate txn here,
                             // however we MUST always provide at least what the remote peer needs
@@ -3746,7 +3760,7 @@ void static ProcessGetData(CNode* pfrom)
                             // no response
                     }
 
-                    // Trigger them to send a getblocks request for the next batch of inventory
+                    // Trigger the peer node to send a getblocks request for the next batch of inventory
                     if (inv.hash == pfrom->hashContinue)
                     {
                         // Bypass PushInventory, this must send even if redundant,
@@ -4060,7 +4074,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             if (inv.type == MSG_BLOCK) {
                 UpdateBlockAvailability(pfrom->GetId(), inv.hash);
                 if (!fAlreadyHave && !fImporting && !fReindex && !mapBlocksInFlight.count(inv.hash)) {
-                    // First request the headers preceeding the announced block. In the normal fully-synced
+                    // First request the headers preceding the announced block. In the normal fully-synced
                     // case where a new block is announced that succeeds the current tip (no reorganization),
                     // there are no such headers.
                     // Secondly, and only when we are close to being synced, we request the announced block directly,
@@ -4142,8 +4156,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             pfrom->PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
             if (--nLimit <= 0)
             {
-                // When this block is requested, we'll send an inv that'll make them
-                // getblocks the next batch of inventory.
+                // When this block is requested, we'll send an inv that'll
+                // trigger the peer to getblocks the next batch of inventory.
                 LogPrint("net", "  getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
                 pfrom->hashContinue = pindex->GetBlockHash();
                 break;
@@ -4380,9 +4394,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
     // This asymmetric behavior for inbound and outbound connections was introduced
     // to prevent a fingerprinting attack: an attacker can send specific fake addresses
-    // to users' AddrMan and later request them by sending getaddr messages. 
-    // Making users (which are behind NAT and can only make outgoing connections) ignore 
-    // getaddr message mitigates the attack.
+    // to users' AddrMan and later request them by sending getaddr messages.
+    // Making nodes which are behind NAT and can only make outgoing connections ignore
+    // the getaddr message mitigates the attack.
     else if ((strCommand == "getaddr") && (pfrom->fInbound))
     {
         pfrom->vAddrToSend.clear();
@@ -4467,7 +4481,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     // Nonce mismatches are normal when pings are overlapping
                     sProblem = "Nonce mismatch";
                     if (nonce == 0) {
-                        // This is most likely a bug in another implementation somewhere, cancel this ping
+                        // This is most likely a bug in another implementation somewhere; cancel this ping
                         bPingFinished = true;
                         sProblem = "Nonce zero";
                     }
@@ -4476,7 +4490,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 sProblem = "Unsolicited pong without ping";
             }
         } else {
-            // This is most likely a bug in another implementation somewhere, cancel this ping
+            // This is most likely a bug in another implementation somewhere; cancel this ping
             bPingFinished = true;
             sProblem = "Short payload";
         }
@@ -4735,7 +4749,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
 {
     const Consensus::Params& consensusParams = Params().GetConsensus();
     {
-        // Don't send anything until we get their version message
+        // Don't send anything until we get its version message
         if (pto->nVersion == 0)
             return true;
 
@@ -4919,7 +4933,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
         // In case there is a block that has been in flight from this peer for (2 + 0.5 * N) times the block interval
         // (with N the number of validated blocks that were in flight at the time it was requested), disconnect due to
         // timeout. We compensate for in-flight blocks to prevent killing off peers due to our own downstream link
-        // being saturated. We only count validated in-flight blocks so peers can't advertize nonexisting block hashes
+        // being saturated. We only count validated in-flight blocks so peers can't advertise non-existing block hashes
         // to unreasonably increase our timeout.
         if (!pto->fDisconnect && state.vBlocksInFlight.size() > 0 && state.vBlocksInFlight.front().nTime < nNow - 500000 * consensusParams.nPowTargetSpacing * (4 + state.vBlocksInFlight.front().nValidatedQueuedBefore)) {
             LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", state.vBlocksInFlight.front().hash.ToString(), pto->id);