1 files changed, 85 insertions, 65 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 62f1cd151..3a07190a6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -74,7 +74,6 @@ bool fHavePruned = false;
 bool fPruneMode = false;
 bool fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG;
 bool fRequireStandard = true;
-unsigned int nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP;
 bool fCheckBlockIndex = false;
 bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
 size_t nCoinCacheUsage = 5000 * 300;
@@ -107,11 +106,6 @@ map<uint256, COrphanTx> mapOrphanTransactions GUARDED_BY(cs_main);
 map<COutPoint, set<map<uint256, COrphanTx>::iterator, IteratorComparator>> mapOrphanTransactionsByPrev GUARDED_BY(cs_main);
 void EraseOrphansFor(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
-/**
- * Returns true if there are nRequired or more blocks of minVersion or above
- * in the last Consensus::Params::nMajorityWindow blocks, starting at pstart and going backwards.
- */
-static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned nRequired, const Consensus::Params& consensusParams);
 static void CheckBlockIndex(const Consensus::Params& consensusParams);
 
 /** Constant stuff for coinbase transactions we create: */
@@ -276,6 +270,8 @@ struct CNodeState {
     CBlockIndex *pindexLastCommonBlock;
     //! The best header we have sent our peer.
     CBlockIndex *pindexBestHeaderSent;
+    //! Length of current-streak of unconnecting headers announcements
+    int nUnconnectingHeaders;
     //! Whether we've started headers synchronization with this peer.
     bool fSyncStarted;
     //! Since when we're stalling block download progress (in microseconds), or 0.
@@ -304,6 +300,7 @@ struct CNodeState {
         hashLastUnknownBlock.SetNull();
         pindexLastCommonBlock = NULL;
         pindexBestHeaderSent = NULL;
+        nUnconnectingHeaders = 0;
         fSyncStarted = false;
         nStallingSince = 0;
         nDownloadingSince = 0;
@@ -691,8 +688,8 @@ bool AddOrphanTx(const CTransaction& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(c
     // have been mined or received.
     // 100 orphans, each of which is at most 99,999 bytes big is
     // at most 10 megabytes of orphans and somewhat more byprev index (in the worst case):
-    unsigned int sz = GetTransactionCost(tx);
-    if (sz >= MAX_STANDARD_TX_COST)
+    unsigned int sz = GetTransactionWeight(tx);
+    if (sz >= MAX_STANDARD_TX_WEIGHT)
     {
         LogPrint("mempool", "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString());
         return false;
@@ -785,7 +782,7 @@ bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime)
         return true;
     if ((int64_t)tx.nLockTime < ((int64_t)tx.nLockTime < LOCKTIME_THRESHOLD ? (int64_t)nBlockHeight : nBlockTime))
         return true;
-    BOOST_FOREACH(const CTxIn& txin, tx.vin) {
+    for (const auto& txin : tx.vin) {
         if (!(txin.nSequence == CTxIn::SEQUENCE_FINAL))
             return false;
     }
@@ -999,11 +996,11 @@ bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp, bool
 unsigned int GetLegacySigOpCount(const CTransaction& tx)
 {
     unsigned int nSigOps = 0;
-    BOOST_FOREACH(const CTxIn& txin, tx.vin)
+    for (const auto& txin : tx.vin)
     {
         nSigOps += txin.scriptSig.GetSigOpCount(false);
     }
-    BOOST_FOREACH(const CTxOut& txout, tx.vout)
+    for (const auto& txout : tx.vout)
     {
         nSigOps += txout.scriptPubKey.GetSigOpCount(false);
     }
@@ -1061,7 +1058,7 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state)
 
     // Check for negative or overflow output values
     CAmount nValueOut = 0;
-    BOOST_FOREACH(const CTxOut& txout, tx.vout)
+    for (const auto& txout : tx.vout)
     {
         if (txout.nValue < 0)
             return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-negative");
@@ -1074,7 +1071,7 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state)
 
     // Check for duplicate inputs
     set<COutPoint> vInOutPoints;
-    BOOST_FOREACH(const CTxIn& txin, tx.vin)
+    for (const auto& txin : tx.vin)
     {
         if (vInOutPoints.count(txin.prevout))
             return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
@@ -1088,7 +1085,7 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state)
     }
     else
     {
-        BOOST_FOREACH(const CTxIn& txin, tx.vin)
+        for (const auto& txin : tx.vin)
             if (txin.prevout.IsNull())
                 return state.DoS(10, false, REJECT_INVALID, "bad-txns-prevout-null");
     }
@@ -1141,13 +1138,14 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
     }
 
     // Reject transactions with witness before segregated witness activates (override with -prematurewitness)
-    if (!GetBoolArg("-prematurewitness",false) && !tx.wit.IsNull() && !IsWitnessEnabled(chainActive.Tip(), Params().GetConsensus())) {
+    bool witnessEnabled = IsWitnessEnabled(chainActive.Tip(), Params().GetConsensus());
+    if (!GetBoolArg("-prematurewitness",false) && !tx.wit.IsNull() && !witnessEnabled) {
         return state.DoS(0, false, REJECT_NONSTANDARD, "no-witness-yet", true);
     }
 
     // Rather not work on nonstandard transactions (unless -testnet/-regtest)
     string reason;
-    if (fRequireStandard && !IsStandardTx(tx, reason))
+    if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
         return state.DoS(0, false, REJECT_NONSTANDARD, reason);
 
     // Only accept nLockTime-using transactions that can be mined in the next
@@ -1293,7 +1291,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
         // itself can contain sigops MAX_STANDARD_TX_SIGOPS is less than
         // MAX_BLOCK_SIGOPS; we still consider this an invalid rather than
         // merely non-standard transaction.
-        if ((nSigOpsCost > MAX_STANDARD_TX_SIGOPS_COST) || (nBytesPerSigOp && nSigOpsCost > nSize * WITNESS_SCALE_FACTOR / nBytesPerSigOp))
+        if (nSigOpsCost > MAX_STANDARD_TX_SIGOPS_COST)
             return state.DoS(0, false, REJECT_NONSTANDARD, "bad-txns-too-many-sigops", false,
                 strprintf("%d", nSigOpsCost));
 
@@ -2369,15 +2367,13 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
 
     unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
 
-    // Start enforcing the DERSIG (BIP66) rules, for block.nVersion=3 blocks,
-    // when 75% of the network has upgraded:
-    if (block.nVersion >= 3 && IsSuperMajority(3, pindex->pprev, chainparams.GetConsensus().nMajorityEnforceBlockUpgrade, chainparams.GetConsensus())) {
+    // Start enforcing the DERSIG (BIP66) rule
+    if (pindex->nHeight >= chainparams.GetConsensus().BIP66Height) {
         flags |= SCRIPT_VERIFY_DERSIG;
     }
 
-    // Start enforcing CHECKLOCKTIMEVERIFY, (BIP65) for block.nVersion=4
-    // blocks, when 75% of the network has upgraded:
-    if (block.nVersion >= 4 && IsSuperMajority(4, pindex->pprev, chainparams.GetConsensus().nMajorityEnforceBlockUpgrade, chainparams.GetConsensus())) {
+    // Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule
+    if (pindex->nHeight >= chainparams.GetConsensus().BIP65Height) {
         flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
     }
 
@@ -3401,13 +3397,13 @@ bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::P
             return state.DoS(100, false, REJECT_INVALID, "bad-cb-multiple", false, "more than one coinbase");
 
     // Check transactions
-    BOOST_FOREACH(const CTransaction& tx, block.vtx)
+    for (const auto& tx : block.vtx)
         if (!CheckTransaction(tx, state))
             return state.Invalid(false, state.GetRejectCode(), state.GetRejectReason(),
                                  strprintf("Transaction check failed (tx hash %s) %s", tx.GetHash().ToString(), state.GetDebugMessage()));
 
     unsigned int nSigOps = 0;
-    BOOST_FOREACH(const CTransaction& tx, block.vtx)
+    for (const auto& tx : block.vtx)
     {
         nSigOps += GetLegacySigOpCount(tx);
     }
@@ -3499,8 +3495,9 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc
     return commitment;
 }
 
-bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, CBlockIndex * const pindexPrev, int64_t nAdjustedTime)
+bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev, int64_t nAdjustedTime)
 {
+    const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;
     // Check proof of work
     if (block.nBits != GetNextWorkRequired(pindexPrev, &block, consensusParams))
         return state.DoS(100, false, REJECT_INVALID, "bad-diffbits", false, "incorrect proof of work");
@@ -3514,18 +3511,19 @@ bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& sta
         return state.Invalid(false, REJECT_INVALID, "time-too-new", "block timestamp too far in the future");
 
     // Reject outdated version blocks when 95% (75% on testnet) of the network has upgraded:
-    for (int32_t version = 2; version < 5; ++version) // check for version 2, 3 and 4 upgrades
-        if (block.nVersion < version && IsSuperMajority(version, pindexPrev, consensusParams.nMajorityRejectBlockOutdated, consensusParams))
-            return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", version - 1),
-                                 strprintf("rejected nVersion=0x%08x block", version - 1));
+    // check for version 2, 3 and 4 upgrades
+    if((block.nVersion < 2 && nHeight >= consensusParams.BIP34Height) ||
+       (block.nVersion < 3 && nHeight >= consensusParams.BIP66Height) ||
+       (block.nVersion < 4 && nHeight >= consensusParams.BIP65Height))
+            return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
+                                 strprintf("rejected nVersion=0x%08x block", block.nVersion));
 
     return true;
 }
 
-bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIndex * const pindexPrev)
+bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
 {
     const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;
-    const Consensus::Params& consensusParams = Params().GetConsensus();
 
     // Start enforcing BIP113 (Median Time Past) using versionbits logic.
     int nLockTimeFlags = 0;
@@ -3538,15 +3536,14 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIn
                               : block.GetBlockTime();
 
     // Check that all transactions are finalized
-    BOOST_FOREACH(const CTransaction& tx, block.vtx) {
+    for (const auto& tx : block.vtx) {
         if (!IsFinalTx(tx, nHeight, nLockTimeCutoff)) {
             return state.DoS(10, false, REJECT_INVALID, "bad-txns-nonfinal", false, "non-final transaction");
         }
     }
 
-    // Enforce block.nVersion=2 rule that the coinbase starts with serialized block height
-    // if 750 of the last 1,000 blocks are version 2 or greater (51/100 if testnet):
-    if (block.nVersion >= 2 && IsSuperMajority(2, pindexPrev, consensusParams.nMajorityEnforceBlockUpgrade, consensusParams))
+    // Enforce rule that the coinbase starts with serialized block height
+    if (nHeight >= consensusParams.BIP34Height)
     {
         CScript expect = CScript() << nHeight;
         if (block.vtx[0].vin[0].scriptSig.size() < expect.size() ||
@@ -3564,7 +3561,7 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIn
     //   {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness nonce). In case there are
     //   multiple, the last one is used.
     bool fHaveWitness = false;
-    if (IsWitnessEnabled(pindexPrev, consensusParams)) {
+    if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_ACTIVE) {
         int commitpos = GetWitnessCommitmentIndex(block);
         if (commitpos != -1) {
             bool malleated = false;
@@ -3573,11 +3570,11 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIn
             // already does not permit it, it is impossible to trigger in the
             // witness tree.
             if (block.vtx[0].wit.vtxinwit.size() != 1 || block.vtx[0].wit.vtxinwit[0].scriptWitness.stack.size() != 1 || block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0].size() != 32) {
-                return state.DoS(100, error("%s : invalid witness nonce size", __func__), REJECT_INVALID, "bad-witness-nonce-size", true);
+                return state.DoS(100, false, REJECT_INVALID, "bad-witness-nonce-size", true, strprintf("%s : invalid witness nonce size", __func__));
             }
             CHash256().Write(hashWitness.begin(), 32).Write(&block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0][0], 32).Finalize(hashWitness.begin());
             if (memcmp(hashWitness.begin(), &block.vtx[0].vout[commitpos].scriptPubKey[6], 32)) {
-                return state.DoS(100, error("%s : witness merkle commitment mismatch", __func__), REJECT_INVALID, "bad-witness-merkle-match", true);
+                return state.DoS(100, false, REJECT_INVALID, "bad-witness-merkle-match", true, strprintf("%s : witness merkle commitment mismatch", __func__));
             }
             fHaveWitness = true;
         }
@@ -3587,19 +3584,19 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIn
     if (!fHaveWitness) {
         for (size_t i = 0; i < block.vtx.size(); i++) {
             if (!block.vtx[i].wit.IsNull()) {
-                return state.DoS(100, error("%s : unexpected witness data found", __func__), REJECT_INVALID, "unexpected-witness", true);
+                return state.DoS(100, false, REJECT_INVALID, "unexpected-witness", true, strprintf("%s : unexpected witness data found", __func__));
             }
         }
     }
 
     // After the coinbase witness nonce and commitment are verified,
-    // we can check if the block cost passes (before we've checked the
-    // coinbase witness, it would be possible for the cost to be too
+    // we can check if the block weight passes (before we've checked the
+    // coinbase witness, it would be possible for the weight to be too
     // large by filling up the coinbase witness, which doesn't change
     // the block hash, so we couldn't mark the block as permanently
     // failed).
-    if (GetBlockCost(block) > MAX_BLOCK_COST) {
-        return state.DoS(100, error("ContextualCheckBlock(): cost limit failed"), REJECT_INVALID, "bad-blk-cost");
+    if (GetBlockWeight(block) > MAX_BLOCK_WEIGHT) {
+        return state.DoS(100, false, REJECT_INVALID, "bad-blk-weight", false, strprintf("%s : weight limit failed", __func__));
     }
 
     return true;
@@ -3686,7 +3683,8 @@ static bool AcceptBlock(const CBlock& block, CValidationState& state, const CCha
     }
     if (fNewBlock) *fNewBlock = true;
 
-    if ((!CheckBlock(block, state, chainparams.GetConsensus(), GetAdjustedTime())) || !ContextualCheckBlock(block, state, pindex->pprev)) {
+    if (!CheckBlock(block, state, chainparams.GetConsensus(), GetAdjustedTime()) ||
+        !ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindex->pprev)) {
         if (state.IsInvalid() && !state.CorruptionPossible()) {
             pindex->nStatus |= BLOCK_FAILED_VALID;
             setDirtyBlockIndex.insert(pindex);
@@ -3719,19 +3717,6 @@ static bool AcceptBlock(const CBlock& block, CValidationState& state, const CCha
     return true;
 }
 
-static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned nRequired, const Consensus::Params& consensusParams)
-{
-    unsigned int nFound = 0;
-    for (int i = 0; i < consensusParams.nMajorityWindow && nFound < nRequired && pstart != NULL; i++)
-    {
-        if (pstart->nVersion >= minVersion)
-            ++nFound;
-        pstart = pstart->pprev;
-    }
-    return (nFound >= nRequired);
-}
-
-
 bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp)
 {
     {
@@ -3777,7 +3762,7 @@ bool TestBlockValidity(CValidationState& state, const CChainParams& chainparams,
         return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__, FormatStateMessage(state));
     if (!CheckBlock(block, state, chainparams.GetConsensus(), fCheckPOW, fCheckMerkleRoot))
         return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state));
-    if (!ContextualCheckBlock(block, state, pindexPrev))
+    if (!ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindexPrev))
         return error("%s: Consensus::ContextualCheckBlock: %s", __func__, FormatStateMessage(state));
     if (!ConnectBlock(block, state, &indexDummy, viewNew, chainparams, true))
         return false;
@@ -4097,7 +4082,7 @@ bool CVerifyDB::VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview,
     int nGoodTransactions = 0;
     CValidationState state;
     int reportDone = 0;
-    LogPrintf("[0%]...");
+    LogPrintf("[0%%]...");
     for (CBlockIndex* pindex = chainActive.Tip(); pindex && pindex->pprev; pindex = pindex->pprev)
     {
         boost::this_thread::interruption_point();
@@ -4328,8 +4313,6 @@ bool InitBlockIndex(const CChainParams& chainparams)
             CBlockIndex *pindex = AddToBlockIndex(block);
             if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
                 return error("LoadBlockIndex(): genesis block not accepted");
-            if (!ActivateBestChain(state, chainparams, &block))
-                return error("LoadBlockIndex(): genesis block cannot be activated");
             // Force a chainstate write so that when we VerifyDB in a moment, it doesn't check stale data
             return FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
         } catch (const std::runtime_error& e) {
@@ -5340,7 +5323,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
         BlockMap::iterator it = mapBlockIndex.find(req.blockhash);
         if (it == mapBlockIndex.end() || !(it->second->nStatus & BLOCK_HAVE_DATA)) {
-            Misbehaving(pfrom->GetId(), 100);
             LogPrintf("Peer %d sent us a getblocktxn for a block we don't have", pfrom->id);
             return true;
         }
@@ -5624,8 +5606,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 std::vector<CInv> vInv(1);
                 vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                 pfrom->PushMessage(NetMsgType::GETDATA, vInv);
-                return true;
             }
+            return true;
         }
 
         // If we're not close to tip yet, give up and let parallel block fetch work its magic
@@ -5773,6 +5755,35 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             return true;
         }
 
+        CNodeState *nodestate = State(pfrom->GetId());
+
+        // If this looks like it could be a block announcement (nCount <
+        // MAX_BLOCKS_TO_ANNOUNCE), use special logic for handling headers that
+        // don't connect:
+        // - Send a getheaders message in response to try to connect the chain.
+        // - The peer can send up to MAX_UNCONNECTING_HEADERS in a row that
+        //   don't connect before giving DoS points
+        // - Once a headers message is received that is valid and does connect,
+        //   nUnconnectingHeaders gets reset back to 0.
+        if (mapBlockIndex.find(headers[0].hashPrevBlock) == mapBlockIndex.end() && nCount < MAX_BLOCKS_TO_ANNOUNCE) {
+            nodestate->nUnconnectingHeaders++;
+            pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256());
+            LogPrint("net", "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d, nUnconnectingHeaders=%d)\n",
+                    headers[0].GetHash().ToString(),
+                    headers[0].hashPrevBlock.ToString(),
+                    pindexBestHeader->nHeight,
+                    pfrom->id, nodestate->nUnconnectingHeaders);
+            // Set hashLastUnknownBlock for this peer, so that if we
+            // eventually get the headers - even from a different peer -
+            // we can use this peer to download.
+            UpdateBlockAvailability(pfrom->GetId(), headers.back().GetHash());
+
+            if (nodestate->nUnconnectingHeaders % MAX_UNCONNECTING_HEADERS == 0) {
+                Misbehaving(pfrom->GetId(), 20);
+            }
+            return true;
+        }
+
         CBlockIndex *pindexLast = NULL;
         BOOST_FOREACH(const CBlockHeader& header, headers) {
             CValidationState state;
@@ -5790,6 +5801,11 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             }
         }
 
+        if (nodestate->nUnconnectingHeaders > 0) {
+            LogPrint("net", "peer=%d: resetting nUnconnectingHeaders (%d -> 0)\n", pfrom->id, nodestate->nUnconnectingHeaders);
+        }
+        nodestate->nUnconnectingHeaders = 0;
+
         assert(pindexLast);
         UpdateBlockAvailability(pfrom->GetId(), pindexLast->GetBlockHash());
 
@@ -5802,7 +5818,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         }
 
         bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus());
-        CNodeState *nodestate = State(pfrom->GetId());
         // If this set of headers is valid and ends in a block with at least as
         // much work as our tip, download as much as possible.
         if (fCanDirectFetch && pindexLast->IsValid(BLOCK_VALID_TREE) && chainActive.Tip()->nChainWork <= pindexLast->nChainWork) {
@@ -6110,6 +6125,11 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         }
     }
 
+    else if (strCommand == NetMsgType::NOTFOUND) {
+        // We do not care about the NOTFOUND message, but logging an Unknown Command
+        // message would be undesirable as we transmit it ourselves.
+    }
+
     else {
         // Ignore unknown commands for extensibility
         LogPrint("net", "Unknown command \"%s\" from peer=%d\n", SanitizeString(strCommand), pfrom->id);