diff --git a/src/avalanche/processor.cpp b/src/avalanche/processor.cpp
index bbb56b9e6..f5da9a628 100644
--- a/src/avalanche/processor.cpp
+++ b/src/avalanche/processor.cpp
@@ -1,532 +1,527 @@
 // Copyright (c) 2018-2019 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <avalanche/processor.h>
 
 #include <avalanche/peermanager.h>
 #include <chain.h>
 #include <key_io.h>         // For DecodeSecret
 #include <net_processing.h> // For Misbehaving
 #include <netmessagemaker.h>
 #include <reverse_iterator.h>
 #include <scheduler.h>
 #include <util/bitmanip.h>
 #include <validation.h>
 
 #include <chrono>
 #include <tuple>
 
 /**
  * Run the avalanche event loop every 10ms.
  */
 static constexpr std::chrono::milliseconds AVALANCHE_TIME_STEP{10};
 
 // Unfortunately, the bitcoind codebase is full of global and we are kinda
 // forced into it here.
 std::unique_ptr<avalanche::Processor> g_avalanche;
 
 namespace avalanche {
 
 bool VoteRecord::registerVote(NodeId nodeid, uint32_t error) {
     // We just got a new vote, so there is one less inflight request.
     clearInflightRequest();
 
     // We want to avoid having the same node voting twice in a quorum.
     if (!addNodeToQuorum(nodeid)) {
         return false;
     }
 
     /**
      * The result of the vote is determined from the error code. If the error
      * code is 0, there is no error and therefore the vote is yes. If there is
      * an error, we check the most significant bit to decide if the vote is a no
      * (for instance, the block is invalid) or is the vote inconclusive (for
      * instance, the queried node does not have the block yet).
      */
     votes = (votes << 1) | (error == 0);
     consider = (consider << 1) | (int32_t(error) >= 0);
 
     /**
      * We compute the number of yes and/or no votes as follow:
      *
      * votes:     1010
      * consider:  1100
      *
      * yes votes: 1000 using votes & consider
      * no votes:  0100 using ~votes & consider
      */
     bool yes = countBits(votes & consider & 0xff) > 6;
     if (!yes) {
         bool no = countBits(~votes & consider & 0xff) > 6;
         if (!no) {
             // The round is inconclusive.
             return false;
         }
     }
 
     // If the round is in agreement with previous rounds, increase confidence.
     if (isAccepted() == yes) {
         confidence += 2;
         return getConfidence() == AVALANCHE_FINALIZATION_SCORE;
     }
 
     // The round changed our state. We reset the confidence.
     confidence = yes;
     return true;
 }
 
 bool VoteRecord::addNodeToQuorum(NodeId nodeid) {
     if (nodeid == NO_NODE) {
         // Helpful for testing.
         return true;
     }
 
     // MMIX Linear Congruent Generator.
     const uint64_t r1 =
         6364136223846793005 * uint64_t(nodeid) + 1442695040888963407;
     // Fibonacci hashing.
     const uint64_t r2 = 11400714819323198485ull * (nodeid ^ seed);
     // Combine and extract hash.
     const uint16_t h = (r1 + r2) >> 48;
 
     /**
      * Check if the node is in the filter.
      */
     for (size_t i = 1; i < nodeFilter.size(); i++) {
         if (nodeFilter[(successfulVotes + i) % nodeFilter.size()] == h) {
             return false;
         }
     }
 
     /**
      * Add the node which just voted to the filter.
      */
     nodeFilter[successfulVotes % nodeFilter.size()] = h;
     successfulVotes++;
     return true;
 }
 
 bool VoteRecord::registerPoll() const {
     uint8_t count = inflight.load();
     while (count < AVALANCHE_MAX_INFLIGHT_POLL) {
         if (inflight.compare_exchange_weak(count, count + 1)) {
             return true;
         }
     }
 
     return false;
 }
 
 static bool IsWorthPolling(const CBlockIndex *pindex) {
     AssertLockHeld(cs_main);
 
     if (pindex->nStatus.isInvalid()) {
         // No point polling invalid blocks.
         return false;
     }
 
     if (::ChainstateActive().IsBlockFinalized(pindex)) {
         // There is no point polling finalized block.
         return false;
     }
 
     return true;
 }
 
 class Processor::NotificationsHandler
     : public interfaces::Chain::Notifications {
     Processor *m_processor;
 
 public:
     NotificationsHandler(Processor *p) : m_processor(p) {}
 
     void updatedBlockTip() override {
         LOCK(m_processor->cs_peerManager);
         m_processor->peerManager->updatedBlockTip();
     }
 };
 
 Processor::Processor(interfaces::Chain &chain, CConnman *connmanIn)
     : connman(connmanIn), queryTimeoutDuration(AVALANCHE_DEFAULT_QUERY_TIMEOUT),
       round(0), peerManager(std::make_unique<PeerManager>()) {
     if (gArgs.IsArgSet("-avasessionkey")) {
         sessionKey = DecodeSecret(gArgs.GetArg("-avasessionkey", ""));
     } else {
         // Pick a random key for the session.
         sessionKey.MakeNewKey(true);
     }
 
     // Make sure we get notified of chain state changes.
     chainNotificationsHandler =
         chain.handleNotifications(std::make_shared<NotificationsHandler>(this));
 }
 
 Processor::~Processor() {
     chainNotificationsHandler.reset();
     stopEventLoop();
 }
 
 bool Processor::addBlockToReconcile(const CBlockIndex *pindex) {
     bool isAccepted;
 
     {
         LOCK(cs_main);
         if (!IsWorthPolling(pindex)) {
             // There is no point polling this block.
             return false;
         }
 
         isAccepted = ::ChainActive().Contains(pindex);
     }
 
     return vote_records.getWriteView()
         ->insert(std::make_pair(pindex, VoteRecord(isAccepted)))
         .second;
 }
 
 bool Processor::isAccepted(const CBlockIndex *pindex) const {
     auto r = vote_records.getReadView();
     auto it = r->find(pindex);
     if (it == r.end()) {
         return false;
     }
 
     return it->second.isAccepted();
 }
 
 int Processor::getConfidence(const CBlockIndex *pindex) const {
     auto r = vote_records.getReadView();
     auto it = r->find(pindex);
     if (it == r.end()) {
         return -1;
     }
 
     return it->second.getConfidence();
 }
 
 namespace {
     /**
      * When using TCP, we need to sign all messages as the transport layer is
      * not secure.
      */
     class TCPResponse {
         Response response;
         std::array<uint8_t, 64> sig;
 
     public:
         TCPResponse(Response responseIn, const CKey &key)
             : response(std::move(responseIn)) {
             CHashWriter hasher(SER_GETHASH, 0);
             hasher << response;
             const uint256 hash = hasher.GetHash();
 
             // Now let's sign!
-            std::vector<uint8_t> vchSig;
-            if (key.SignSchnorr(hash, vchSig)) {
-                // Schnorr sigs are 64 bytes in size.
-                assert(vchSig.size() == 64);
-                std::copy(vchSig.begin(), vchSig.end(), sig.begin());
-            } else {
+            if (!key.SignSchnorr(hash, sig)) {
                 sig.fill(0);
             }
         }
 
         // serialization support
         ADD_SERIALIZE_METHODS;
 
         template <typename Stream, typename Operation>
         inline void SerializationOp(Stream &s, Operation ser_action) {
             READWRITE(response);
             READWRITE(sig);
         }
     };
 } // namespace
 
 void Processor::sendResponse(CNode *pfrom, Response response) const {
     connman->PushMessage(
         pfrom, CNetMsgMaker(pfrom->GetSendVersion())
                    .Make(NetMsgType::AVARESPONSE,
                          TCPResponse(std::move(response), sessionKey)));
 }
 
 bool Processor::registerVotes(NodeId nodeid, const Response &response,
                               std::vector<BlockUpdate> &updates) {
     {
         // Save the time at which we can query again.
         LOCK(cs_peerManager);
 
         // FIXME: This will override the time even when we received an old stale
         // message. This should check that the message is indeed the most up to
         // date one before updating the time.
         peerManager->updateNextRequestTime(
             nodeid, std::chrono::steady_clock::now() +
                         std::chrono::milliseconds(response.getCooldown()));
     }
 
     std::vector<CInv> invs;
 
     {
         // Check that the query exists.
         auto w = queries.getWriteView();
         auto it = w->find(std::make_tuple(nodeid, response.getRound()));
         if (it == w.end()) {
             LOCK(cs_main);
             Misbehaving(nodeid, 2, "unexpcted-ava-response");
             return false;
         }
 
         invs = std::move(it->invs);
         w->erase(it);
     }
 
     // Verify that the request and the vote are consistent.
     const std::vector<Vote> &votes = response.GetVotes();
     size_t size = invs.size();
     if (votes.size() != size) {
         LOCK(cs_main);
         Misbehaving(nodeid, 100, "invalid-ava-response-size");
         return false;
     }
 
     for (size_t i = 0; i < size; i++) {
         if (invs[i].hash != votes[i].GetHash()) {
             LOCK(cs_main);
             Misbehaving(nodeid, 100, "invalid-ava-response-content");
             return false;
         }
     }
 
     std::map<CBlockIndex *, Vote> responseIndex;
 
     {
         LOCK(cs_main);
         for (const auto &v : votes) {
             auto pindex = LookupBlockIndex(BlockHash(v.GetHash()));
             if (!pindex) {
                 // This should not happen, but just in case...
                 continue;
             }
 
             if (!IsWorthPolling(pindex)) {
                 // There is no point polling this block.
                 continue;
             }
 
             responseIndex.insert(std::make_pair(pindex, v));
         }
     }
 
     {
         // Register votes.
         auto w = vote_records.getWriteView();
         for (const auto &p : responseIndex) {
             CBlockIndex *pindex = p.first;
             const Vote &v = p.second;
 
             auto it = w->find(pindex);
             if (it == w.end()) {
                 // We are not voting on that item anymore.
                 continue;
             }
 
             auto &vr = it->second;
             if (!vr.registerVote(nodeid, v.GetError())) {
                 // This vote did not provide any extra information, move on.
                 continue;
             }
 
             if (!vr.hasFinalized()) {
                 // This item has note been finalized, so we have nothing more to
                 // do.
                 updates.emplace_back(
                     pindex, vr.isAccepted() ? BlockUpdate::Status::Accepted
                                             : BlockUpdate::Status::Rejected);
                 continue;
             }
 
             // We just finalized a vote. If it is valid, then let the caller
             // know. Either way, remove the item from the map.
             updates.emplace_back(pindex, vr.isAccepted()
                                              ? BlockUpdate::Status::Finalized
                                              : BlockUpdate::Status::Invalid);
             w->erase(it);
         }
     }
 
     return true;
 }
 
 bool Processor::addNode(NodeId nodeid, const Proof &proof,
                         const CPubKey &pubkey) {
     LOCK(cs_peerManager);
     return peerManager->addNode(nodeid, proof, pubkey);
 }
 
 bool Processor::forNode(NodeId nodeid,
                         std::function<bool(const Node &n)> func) const {
     LOCK(cs_peerManager);
     return peerManager->forNode(nodeid, std::move(func));
 }
 
 bool Processor::startEventLoop(CScheduler &scheduler) {
     return eventLoop.startEventLoop(
         scheduler, [this]() { this->runEventLoop(); }, AVALANCHE_TIME_STEP);
 }
 
 bool Processor::stopEventLoop() {
     return eventLoop.stopEventLoop();
 }
 
 std::vector<CInv> Processor::getInvsForNextPoll(bool forPoll) {
     std::vector<CInv> invs;
 
     // First remove all blocks that are not worth polling.
     {
         LOCK(cs_main);
         auto w = vote_records.getWriteView();
         for (auto it = w->begin(); it != w->end();) {
             const CBlockIndex *pindex = it->first;
             if (!IsWorthPolling(pindex)) {
                 w->erase(it++);
             } else {
                 ++it;
             }
         }
     }
 
     auto r = vote_records.getReadView();
     for (const std::pair<const CBlockIndex *const, VoteRecord> &p :
          reverse_iterate(r)) {
         // Check if we can run poll.
         const bool shouldPoll =
             forPoll ? p.second.registerPoll() : p.second.shouldPoll();
         if (!shouldPoll) {
             continue;
         }
 
         // We don't have a decision, we need more votes.
         invs.emplace_back(MSG_BLOCK, p.first->GetBlockHash());
         if (invs.size() >= AVALANCHE_MAX_ELEMENT_POLL) {
             // Make sure we do not produce more invs than specified by the
             // protocol.
             return invs;
         }
     }
 
     return invs;
 }
 
 NodeId Processor::getSuitableNodeToQuery() {
     LOCK(cs_peerManager);
     return peerManager->selectNode();
 }
 
 void Processor::clearTimedoutRequests() {
     auto now = std::chrono::steady_clock::now();
     std::map<CInv, uint8_t> timedout_items{};
 
     {
         // Clear expired requests.
         auto w = queries.getWriteView();
         auto it = w->get<query_timeout>().begin();
         while (it != w->get<query_timeout>().end() && it->timeout < now) {
             for (const auto &i : it->invs) {
                 timedout_items[i]++;
             }
 
             w->get<query_timeout>().erase(it++);
         }
     }
 
     if (timedout_items.empty()) {
         return;
     }
 
     // In flight request accounting.
     for (const auto &p : timedout_items) {
         const CInv &inv = p.first;
         assert(inv.type == MSG_BLOCK);
 
         CBlockIndex *pindex;
 
         {
             LOCK(cs_main);
             pindex = LookupBlockIndex(BlockHash(inv.hash));
             if (!pindex) {
                 continue;
             }
         }
 
         auto w = vote_records.getWriteView();
         auto it = w->find(pindex);
         if (it == w.end()) {
             continue;
         }
 
         it->second.clearInflightRequest(p.second);
     }
 }
 
 void Processor::runEventLoop() {
     // First things first, check if we have requests that timed out and clear
     // them.
     clearTimedoutRequests();
 
     // Make sure there is at least one suitable node to query before gathering
     // invs.
     NodeId nodeid = getSuitableNodeToQuery();
     if (nodeid == NO_NODE) {
         return;
     }
     std::vector<CInv> invs = getInvsForNextPoll();
     if (invs.empty()) {
         return;
     }
 
     do {
         /**
          * If we lost contact to that node, then we remove it from nodeids, but
          * never add the request to queries, which ensures bad nodes get cleaned
          * up over time.
          */
         bool hasSent = connman->ForNode(nodeid, [this, &invs](CNode *pnode) {
             uint64_t current_round = round++;
 
             {
                 // Compute the time at which this requests times out.
                 auto timeout =
                     std::chrono::steady_clock::now() + queryTimeoutDuration;
                 // Register the query.
                 queries.getWriteView()->insert(
                     {pnode->GetId(), current_round, timeout, invs});
                 // Set the timeout.
                 LOCK(cs_peerManager);
                 peerManager->updateNextRequestTime(pnode->GetId(), timeout);
             }
 
             // Send the query to the node.
             connman->PushMessage(
                 pnode, CNetMsgMaker(pnode->GetSendVersion())
                            .Make(NetMsgType::AVAPOLL,
                                  Poll(current_round, std::move(invs))));
             return true;
         });
 
         // Success!
         if (hasSent) {
             return;
         }
 
         {
             // This node is obsolete, delete it.
             LOCK(cs_peerManager);
             peerManager->removeNode(nodeid);
         }
 
         // Get next suitable node to try again
         nodeid = getSuitableNodeToQuery();
     } while (nodeid != NO_NODE);
 }
 
 } // namespace avalanche
diff --git a/src/avalanche/proof.cpp b/src/avalanche/proof.cpp
index c8f6358f7..586e5a641 100644
--- a/src/avalanche/proof.cpp
+++ b/src/avalanche/proof.cpp
@@ -1,132 +1,130 @@
 // Copyright (c) 2020 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <avalanche/proof.h>
 
 #include <avalanche/validation.h>
 #include <coins.h>
 #include <hash.h>
 #include <script/standard.h>
 
 #include <unordered_set>
 
 namespace avalanche {
 
 uint256 Stake::getHash(const ProofId &proofid) const {
     CHashWriter ss(SER_GETHASH, 0);
     ss << proofid;
     ss << *this;
     return ss.GetHash();
 }
 
 bool SignedStake::verify(const ProofId &proofid) const {
-    // Unfortunately, the verify API require a vector.
-    std::vector<uint8_t> vchSig{sig.begin(), sig.end()};
-    return stake.getPubkey().VerifySchnorr(stake.getHash(proofid), vchSig);
+    return stake.getPubkey().VerifySchnorr(stake.getHash(proofid), sig);
 }
 
 ProofId Proof::computeProofId() const {
     CHashWriter ss(SER_GETHASH, 0);
     ss << sequence;
     ss << expirationTime;
     ss << master;
 
     WriteCompactSize(ss, stakes.size());
     for (const SignedStake &s : stakes) {
         ss << s.getStake();
     }
 
     return ProofId(ss.GetHash());
 }
 
 uint32_t Proof::getScore() const {
     Amount total = Amount::zero();
     for (const SignedStake &s : stakes) {
         total += s.getStake().getAmount();
     }
 
     return uint32_t((100 * total) / COIN);
 }
 
 static constexpr Amount PROOF_DUST_THRESOLD = 1 * SATOSHI;
 
 bool Proof::verify(ProofValidationState &state) const {
     if (stakes.empty()) {
         return state.Invalid(ProofValidationResult::NO_STAKE);
     }
 
     std::unordered_set<COutPoint, SaltedOutpointHasher> utxos;
     for (const SignedStake &ss : stakes) {
         const Stake &s = ss.getStake();
         if (s.getAmount() < PROOF_DUST_THRESOLD) {
             return state.Invalid(ProofValidationResult::DUST_THRESOLD);
         }
 
         if (!utxos.insert(s.getUTXO()).second) {
             return state.Invalid(ProofValidationResult::DUPLICATE_STAKE);
         }
 
         if (!ss.verify(proofid)) {
             return state.Invalid(ProofValidationResult::INVALID_SIGNATURE);
         }
     }
 
     return true;
 }
 
 bool Proof::verify(ProofValidationState &state, const CCoinsView &view) const {
     if (!verify(state)) {
         // state is set by verify.
         return false;
     }
 
     for (const SignedStake &ss : stakes) {
         const Stake &s = ss.getStake();
         const COutPoint &utxo = s.getUTXO();
 
         Coin coin;
         if (!view.GetCoin(utxo, coin)) {
             // The coins are not in the UTXO set.
             return state.Invalid(ProofValidationResult::MISSING_UTXO);
         }
 
         if (s.isCoinbase() != coin.IsCoinBase()) {
             return state.Invalid(ProofValidationResult::COINBASE_MISMATCH);
         }
 
         if (s.getHeight() != coin.GetHeight()) {
             return state.Invalid(ProofValidationResult::HEIGHT_MISMATCH);
         }
 
         const CTxOut &out = coin.GetTxOut();
         if (s.getAmount() != out.nValue) {
             // Wrong amount.
             return state.Invalid(ProofValidationResult::AMOUNT_MISMATCH);
         }
 
         CTxDestination dest;
         if (!ExtractDestination(out.scriptPubKey, dest)) {
             // Can't extract destination.
             return state.Invalid(
                 ProofValidationResult::NON_STANDARD_DESTINATION);
         }
 
         PKHash *pkhash = boost::get<PKHash>(&dest);
         if (!pkhash) {
             // Only PKHash are supported.
             return state.Invalid(
                 ProofValidationResult::DESTINATION_NOT_SUPPORTED);
         }
 
         const CPubKey &pubkey = s.getPubkey();
         if (*pkhash != PKHash(pubkey)) {
             // Wrong pubkey.
             return state.Invalid(ProofValidationResult::DESTINATION_MISMATCH);
         }
     }
 
     return true;
 }
 
 } // namespace avalanche
diff --git a/src/avalanche/proofbuilder.cpp b/src/avalanche/proofbuilder.cpp
index 980bb8191..272eb4349 100644
--- a/src/avalanche/proofbuilder.cpp
+++ b/src/avalanche/proofbuilder.cpp
@@ -1,78 +1,73 @@
 // Copyright (c) 2020 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <avalanche/proofbuilder.h>
 
 #include <random.h>
 
 namespace avalanche {
 
 SignedStake ProofBuilder::StakeSigner::sign(const ProofId &proofid) {
     const uint256 h = stake.getHash(proofid);
 
     std::array<uint8_t, 64> sig;
-    std::vector<uint8_t> vchSig;
-    if (key.SignSchnorr(h, vchSig)) {
-        // Schnorr sig are always 64 bytes in size.
-        assert(vchSig.size() == 64);
-        std::copy(vchSig.begin(), vchSig.end(), sig.begin());
-    } else {
+    if (!key.SignSchnorr(h, sig)) {
         sig.fill(0);
     }
 
     return SignedStake(std::move(stake), std::move(sig));
 }
 
 bool ProofBuilder::addUTXO(COutPoint utxo, Amount amount, uint32_t height,
                            bool is_coinbase, CKey key) {
     if (!key.IsValid()) {
         return false;
     }
 
     stakes.emplace_back(
         Stake(std::move(utxo), amount, height, is_coinbase, key.GetPubKey()),
         std::move(key));
     return true;
 }
 
 Proof ProofBuilder::build() {
     const ProofId proofid = getProofId();
 
     std::vector<SignedStake> signedStakes;
     signedStakes.reserve(stakes.size());
 
     for (auto &s : stakes) {
         signedStakes.push_back(s.sign(proofid));
     }
 
     stakes.clear();
     return Proof(sequence, expirationTime, std::move(master),
                  std::move(signedStakes));
 }
 
 ProofId ProofBuilder::getProofId() const {
     CHashWriter ss(SER_GETHASH, 0);
     ss << sequence;
     ss << expirationTime;
     ss << master;
 
     WriteCompactSize(ss, stakes.size());
     for (const auto &s : stakes) {
         ss << s.stake;
     }
 
     return ProofId(ss.GetHash());
 }
 
 Proof ProofBuilder::buildRandom(uint32_t score) {
     CKey key;
     key.MakeNewKey(true);
 
     ProofBuilder pb(0, std::numeric_limits<uint32_t>::max(), CPubKey());
     pb.addUTXO(COutPoint(TxId(GetRandHash()), 0), (int64_t(score) * COIN) / 100,
                0, false, std::move(key));
     return pb.build();
 }
 
 } // namespace avalanche
diff --git a/src/key.cpp b/src/key.cpp
index 6925cbddf..dd28c0ffc 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -1,447 +1,462 @@
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017 The Zcash developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <key.h>
 
 #include <crypto/common.h>
 #include <crypto/hmac_sha512.h>
 #include <random.h>
 
 #include <secp256k1.h>
 #include <secp256k1_recovery.h>
 #include <secp256k1_schnorr.h>
 
 static secp256k1_context *secp256k1_context_sign = nullptr;
 
 /**
  * These functions are taken from the libsecp256k1 distribution and are very
  * ugly.
  */
 
 /**
  * This parses a format loosely based on a DER encoding of the ECPrivateKey type
  * from section C.4 of SEC 1 <http://www.secg.org/sec1-v2.pdf>, with the
  * following caveats:
  *
  * * The octet-length of the SEQUENCE must be encoded as 1 or 2 octets. It is
  * not required to be encoded as one octet if it is less than 256, as DER would
  * require.
  * * The octet-length of the SEQUENCE must not be greater than the remaining
  * length of the key encoding, but need not match it (i.e. the encoding may
  * contain junk after the encoded SEQUENCE).
  * * The privateKey OCTET STRING is zero-filled on the left to 32 octets.
  * * Anything after the encoding of the privateKey OCTET STRING is ignored,
  * whether or not it is validly encoded DER.
  *
  * out32 must point to an output buffer of length at least 32 bytes.
  */
 static int ec_privkey_import_der(const secp256k1_context *ctx, uint8_t *out32,
                                  const uint8_t *privkey, size_t privkeylen) {
     const uint8_t *end = privkey + privkeylen;
     memset(out32, 0, 32);
     /* sequence header */
     if (end - privkey < 1 || *privkey != 0x30u) {
         return 0;
     }
     privkey++;
     /* sequence length constructor */
     if (end - privkey < 1 || !(*privkey & 0x80u)) {
         return 0;
     }
     ptrdiff_t lenb = *privkey & ~0x80u;
     privkey++;
     if (lenb < 1 || lenb > 2) {
         return 0;
     }
     if (end - privkey < lenb) {
         return 0;
     }
     /* sequence length */
     ptrdiff_t len =
         privkey[lenb - 1] | (lenb > 1 ? privkey[lenb - 2] << 8 : 0u);
     privkey += lenb;
     if (end - privkey < len) {
         return 0;
     }
     /* sequence element 0: version number (=1) */
     if (end - privkey < 3 || privkey[0] != 0x02u || privkey[1] != 0x01u ||
         privkey[2] != 0x01u) {
         return 0;
     }
     privkey += 3;
     /* sequence element 1: octet string, up to 32 bytes */
     if (end - privkey < 2 || privkey[0] != 0x04u) {
         return 0;
     }
     ptrdiff_t oslen = privkey[1];
     privkey += 2;
     if (oslen > 32 || end - privkey < oslen) {
         return 0;
     }
     memcpy(out32 + (32 - oslen), privkey, oslen);
     if (!secp256k1_ec_seckey_verify(ctx, out32)) {
         memset(out32, 0, 32);
         return 0;
     }
     return 1;
 }
 
 /**
  * This serializes to a DER encoding of the ECPrivateKey type from section C.4
  * of SEC 1 <http://www.secg.org/sec1-v2.pdf>. The optional parameters and
  * publicKey fields are included.
  *
  * privkey must point to an output buffer of length at least
  * CKey::SIZE bytes. privkeylen must initially be set to the size of
  * the privkey buffer. Upon return it will be set to the number of bytes used in
  * the buffer. key32 must point to a 32-byte raw private key.
  */
 static int ec_privkey_export_der(const secp256k1_context *ctx, uint8_t *privkey,
                                  size_t *privkeylen, const uint8_t *key32,
                                  bool compressed) {
     assert(*privkeylen >= CKey::SIZE);
     secp256k1_pubkey pubkey;
     size_t pubkeylen = 0;
     if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
         *privkeylen = 0;
         return 0;
     }
 
     if (compressed) {
         static const uint8_t begin[] = {0x30, 0x81, 0xD3, 0x02,
                                         0x01, 0x01, 0x04, 0x20};
         static const uint8_t middle[] = {
             0xA0, 0x81, 0x85, 0x30, 0x81, 0x82, 0x02, 0x01, 0x01, 0x30, 0x2C,
             0x06, 0x07, 0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x01, 0x01, 0x02, 0x21,
             0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
             0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
             0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFC, 0x2F,
             0x30, 0x06, 0x04, 0x01, 0x00, 0x04, 0x01, 0x07, 0x04, 0x21, 0x02,
             0x79, 0xBE, 0x66, 0x7E, 0xF9, 0xDC, 0xBB, 0xAC, 0x55, 0xA0, 0x62,
             0x95, 0xCE, 0x87, 0x0B, 0x07, 0x02, 0x9B, 0xFC, 0xDB, 0x2D, 0xCE,
             0x28, 0xD9, 0x59, 0xF2, 0x81, 0x5B, 0x16, 0xF8, 0x17, 0x98, 0x02,
             0x21, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
             0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xBA, 0xAE, 0xDC, 0xE6,
             0xAF, 0x48, 0xA0, 0x3B, 0xBF, 0xD2, 0x5E, 0x8C, 0xD0, 0x36, 0x41,
             0x41, 0x02, 0x01, 0x01, 0xA1, 0x24, 0x03, 0x22, 0x00};
         uint8_t *ptr = privkey;
         memcpy(ptr, begin, sizeof(begin));
         ptr += sizeof(begin);
         memcpy(ptr, key32, 32);
         ptr += 32;
         memcpy(ptr, middle, sizeof(middle));
         ptr += sizeof(middle);
         pubkeylen = CPubKey::COMPRESSED_SIZE;
         secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey,
                                       SECP256K1_EC_COMPRESSED);
         ptr += pubkeylen;
         *privkeylen = ptr - privkey;
         assert(*privkeylen == CKey::COMPRESSED_SIZE);
     } else {
         static const uint8_t begin[] = {0x30, 0x82, 0x01, 0x13, 0x02,
                                         0x01, 0x01, 0x04, 0x20};
         static const uint8_t middle[] = {
             0xA0, 0x81, 0xA5, 0x30, 0x81, 0xA2, 0x02, 0x01, 0x01, 0x30, 0x2C,
             0x06, 0x07, 0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x01, 0x01, 0x02, 0x21,
             0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
             0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
             0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFC, 0x2F,
             0x30, 0x06, 0x04, 0x01, 0x00, 0x04, 0x01, 0x07, 0x04, 0x41, 0x04,
             0x79, 0xBE, 0x66, 0x7E, 0xF9, 0xDC, 0xBB, 0xAC, 0x55, 0xA0, 0x62,
             0x95, 0xCE, 0x87, 0x0B, 0x07, 0x02, 0x9B, 0xFC, 0xDB, 0x2D, 0xCE,
             0x28, 0xD9, 0x59, 0xF2, 0x81, 0x5B, 0x16, 0xF8, 0x17, 0x98, 0x48,
             0x3A, 0xDA, 0x77, 0x26, 0xA3, 0xC4, 0x65, 0x5D, 0xA4, 0xFB, 0xFC,
             0x0E, 0x11, 0x08, 0xA8, 0xFD, 0x17, 0xB4, 0x48, 0xA6, 0x85, 0x54,
             0x19, 0x9C, 0x47, 0xD0, 0x8F, 0xFB, 0x10, 0xD4, 0xB8, 0x02, 0x21,
             0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
             0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xBA, 0xAE, 0xDC, 0xE6, 0xAF,
             0x48, 0xA0, 0x3B, 0xBF, 0xD2, 0x5E, 0x8C, 0xD0, 0x36, 0x41, 0x41,
             0x02, 0x01, 0x01, 0xA1, 0x44, 0x03, 0x42, 0x00};
         uint8_t *ptr = privkey;
         memcpy(ptr, begin, sizeof(begin));
         ptr += sizeof(begin);
         memcpy(ptr, key32, 32);
         ptr += 32;
         memcpy(ptr, middle, sizeof(middle));
         ptr += sizeof(middle);
         pubkeylen = CPubKey::SIZE;
         secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey,
                                       SECP256K1_EC_UNCOMPRESSED);
         ptr += pubkeylen;
         *privkeylen = ptr - privkey;
         assert(*privkeylen == CKey::SIZE);
     }
     return 1;
 }
 
 bool CKey::Check(const uint8_t *vch) {
     return secp256k1_ec_seckey_verify(secp256k1_context_sign, vch);
 }
 
 void CKey::MakeNewKey(bool fCompressedIn) {
     do {
         GetStrongRandBytes(keydata.data(), keydata.size());
     } while (!Check(keydata.data()));
     fValid = true;
     fCompressed = fCompressedIn;
 }
 
 bool CKey::Negate() {
     assert(fValid);
     return secp256k1_ec_privkey_negate(secp256k1_context_sign, keydata.data());
 }
 
 CPrivKey CKey::GetPrivKey() const {
     assert(fValid);
     CPrivKey privkey;
     int ret;
     size_t privkeylen;
     privkey.resize(SIZE);
     privkeylen = SIZE;
     ret = ec_privkey_export_der(secp256k1_context_sign, privkey.data(),
                                 &privkeylen, begin(), fCompressed);
     assert(ret);
     privkey.resize(privkeylen);
     return privkey;
 }
 
 CPubKey CKey::GetPubKey() const {
     assert(fValid);
     secp256k1_pubkey pubkey;
     size_t clen = CPubKey::SIZE;
     CPubKey result;
     int ret =
         secp256k1_ec_pubkey_create(secp256k1_context_sign, &pubkey, begin());
     assert(ret);
     secp256k1_ec_pubkey_serialize(
         secp256k1_context_sign, (uint8_t *)result.begin(), &clen, &pubkey,
         fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
     assert(result.size() == clen);
     assert(result.IsValid());
     return result;
 }
 
 // Check that the sig has a low R value and will be less than 71 bytes
 static bool SigHasLowR(const secp256k1_ecdsa_signature *sig) {
     uint8_t compact_sig[64];
     secp256k1_ecdsa_signature_serialize_compact(secp256k1_context_sign,
                                                 compact_sig, sig);
 
     // In DER serialization, all values are interpreted as big-endian, signed
     // integers. The highest bit in the integer indicates its signed-ness; 0 is
     // positive, 1 is negative. When the value is interpreted as a negative
     // integer, it must be converted to a positive value by prepending a 0x00
     // byte so that the highest bit is 0. We can avoid this prepending by
     // ensuring that our highest bit is always 0, and thus we must check that
     // the first byte is less than 0x80.
     return compact_sig[0] < 0x80;
 }
 
 bool CKey::SignECDSA(const uint256 &hash, std::vector<uint8_t> &vchSig,
                      bool grind, uint32_t test_case) const {
     if (!fValid) {
         return false;
     }
     vchSig.resize(CPubKey::SIGNATURE_SIZE);
     size_t nSigLen = CPubKey::SIGNATURE_SIZE;
     uint8_t extra_entropy[32] = {0};
     WriteLE32(extra_entropy, test_case);
     secp256k1_ecdsa_signature sig;
     uint32_t counter = 0;
     int ret =
         secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(),
                              begin(), secp256k1_nonce_function_rfc6979,
                              (!grind && test_case) ? extra_entropy : nullptr);
 
     // Grind for low R
     while (ret && !SigHasLowR(&sig) && grind) {
         WriteLE32(extra_entropy, ++counter);
         ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(),
                                    begin(), secp256k1_nonce_function_rfc6979,
                                    extra_entropy);
     }
     assert(ret);
     secp256k1_ecdsa_signature_serialize_der(secp256k1_context_sign,
                                             vchSig.data(), &nSigLen, &sig);
     vchSig.resize(nSigLen);
     return true;
 }
 
-bool CKey::SignSchnorr(const uint256 &hash, std::vector<uint8_t> &vchSig,
-                       uint32_t test_case) const {
-    if (!fValid) {
+static bool DoSignSchnorr(const CKey &key, const uint256 &hash, uint8_t *buf,
+                          uint32_t test_case) {
+    if (!key.IsValid()) {
         return false;
     }
-    vchSig.resize(64);
+
     uint8_t extra_entropy[32] = {0};
     WriteLE32(extra_entropy, test_case);
 
     int ret = secp256k1_schnorr_sign(
-        secp256k1_context_sign, &vchSig[0], hash.begin(), begin(),
+        secp256k1_context_sign, buf, hash.begin(), key.begin(),
         secp256k1_nonce_function_rfc6979, test_case ? extra_entropy : nullptr);
     assert(ret);
     return true;
 }
 
+bool CKey::SignSchnorr(const uint256 &hash,
+                       std::array<uint8_t, CPubKey::SCHNORR_SIZE> &sig,
+                       uint32_t test_case) const {
+    return DoSignSchnorr(*this, hash, sig.data(), test_case);
+}
+
+bool CKey::SignSchnorr(const uint256 &hash, std::vector<uint8_t> &vchSig,
+                       uint32_t test_case) const {
+    if (!fValid) {
+        return false;
+    }
+    vchSig.resize(CPubKey::SCHNORR_SIZE);
+    return DoSignSchnorr(*this, hash, vchSig.data(), test_case);
+}
+
 bool CKey::VerifyPubKey(const CPubKey &pubkey) const {
     if (pubkey.IsCompressed() != fCompressed) {
         return false;
     }
     uint8_t rnd[8];
     std::string str = "Bitcoin key verification\n";
     GetRandBytes(rnd, sizeof(rnd));
     uint256 hash;
     CHash256()
         .Write((uint8_t *)str.data(), str.size())
         .Write(rnd, sizeof(rnd))
         .Finalize(hash.begin());
     std::vector<uint8_t> vchSig;
     SignECDSA(hash, vchSig);
     return pubkey.VerifyECDSA(hash, vchSig);
 }
 
 bool CKey::SignCompact(const uint256 &hash,
                        std::vector<uint8_t> &vchSig) const {
     if (!fValid) {
         return false;
     }
     vchSig.resize(CPubKey::COMPACT_SIGNATURE_SIZE);
     int rec = -1;
     secp256k1_ecdsa_recoverable_signature sig;
     int ret = secp256k1_ecdsa_sign_recoverable(
         secp256k1_context_sign, &sig, hash.begin(), begin(),
         secp256k1_nonce_function_rfc6979, nullptr);
     assert(ret);
     ret = secp256k1_ecdsa_recoverable_signature_serialize_compact(
         secp256k1_context_sign, &vchSig[1], &rec, &sig);
     assert(ret);
     assert(rec != -1);
     vchSig[0] = 27 + rec + (fCompressed ? 4 : 0);
     return true;
 }
 
 bool CKey::Load(const CPrivKey &privkey, const CPubKey &vchPubKey,
                 bool fSkipCheck = false) {
     if (!ec_privkey_import_der(secp256k1_context_sign, (uint8_t *)begin(),
                                privkey.data(), privkey.size())) {
         return false;
     }
     fCompressed = vchPubKey.IsCompressed();
     fValid = true;
 
     if (fSkipCheck) {
         return true;
     }
 
     return VerifyPubKey(vchPubKey);
 }
 
 bool CKey::Derive(CKey &keyChild, ChainCode &ccChild, unsigned int nChild,
                   const ChainCode &cc) const {
     assert(IsValid());
     assert(IsCompressed());
     std::vector<uint8_t, secure_allocator<uint8_t>> vout(64);
     if ((nChild >> 31) == 0) {
         CPubKey pubkey = GetPubKey();
         assert(pubkey.size() == CPubKey::COMPRESSED_SIZE);
         BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin() + 1, vout.data());
     } else {
         assert(size() == 32);
         BIP32Hash(cc, nChild, 0, begin(), vout.data());
     }
     memcpy(ccChild.begin(), vout.data() + 32, 32);
     memcpy((uint8_t *)keyChild.begin(), begin(), 32);
     bool ret = secp256k1_ec_privkey_tweak_add(
         secp256k1_context_sign, (uint8_t *)keyChild.begin(), vout.data());
     keyChild.fCompressed = true;
     keyChild.fValid = ret;
     return ret;
 }
 
 bool CExtKey::Derive(CExtKey &out, unsigned int _nChild) const {
     out.nDepth = nDepth + 1;
     CKeyID id = key.GetPubKey().GetID();
     memcpy(&out.vchFingerprint[0], &id, 4);
     out.nChild = _nChild;
     return key.Derive(out.key, out.chaincode, _nChild, chaincode);
 }
 
 void CExtKey::SetSeed(const uint8_t *seed, unsigned int nSeedLen) {
     static const uint8_t hashkey[] = {'B', 'i', 't', 'c', 'o', 'i',
                                       'n', ' ', 's', 'e', 'e', 'd'};
     std::vector<uint8_t, secure_allocator<uint8_t>> vout(64);
     CHMAC_SHA512(hashkey, sizeof(hashkey))
         .Write(seed, nSeedLen)
         .Finalize(vout.data());
     key.Set(vout.data(), vout.data() + 32, true);
     memcpy(chaincode.begin(), vout.data() + 32, 32);
     nDepth = 0;
     nChild = 0;
     memset(vchFingerprint, 0, sizeof(vchFingerprint));
 }
 
 CExtPubKey CExtKey::Neuter() const {
     CExtPubKey ret;
     ret.nDepth = nDepth;
     memcpy(&ret.vchFingerprint[0], &vchFingerprint[0], 4);
     ret.nChild = nChild;
     ret.pubkey = key.GetPubKey();
     ret.chaincode = chaincode;
     return ret;
 }
 
 void CExtKey::Encode(uint8_t code[BIP32_EXTKEY_SIZE]) const {
     code[0] = nDepth;
     memcpy(code + 1, vchFingerprint, 4);
     code[5] = (nChild >> 24) & 0xFF;
     code[6] = (nChild >> 16) & 0xFF;
     code[7] = (nChild >> 8) & 0xFF;
     code[8] = (nChild >> 0) & 0xFF;
     memcpy(code + 9, chaincode.begin(), 32);
     code[41] = 0;
     assert(key.size() == 32);
     memcpy(code + 42, key.begin(), 32);
 }
 
 void CExtKey::Decode(const uint8_t code[BIP32_EXTKEY_SIZE]) {
     nDepth = code[0];
     memcpy(vchFingerprint, code + 1, 4);
     nChild = (code[5] << 24) | (code[6] << 16) | (code[7] << 8) | code[8];
     memcpy(chaincode.begin(), code + 9, 32);
     key.Set(code + 42, code + BIP32_EXTKEY_SIZE, true);
 }
 
 bool ECC_InitSanityCheck() {
     CKey key;
     key.MakeNewKey(true);
     CPubKey pubkey = key.GetPubKey();
     return key.VerifyPubKey(pubkey);
 }
 
 void ECC_Start() {
     assert(secp256k1_context_sign == nullptr);
 
     secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);
     assert(ctx != nullptr);
 
     {
         // Pass in a random blinding seed to the secp256k1 context.
         std::vector<uint8_t, secure_allocator<uint8_t>> vseed(32);
         GetRandBytes(vseed.data(), 32);
         bool ret = secp256k1_context_randomize(ctx, vseed.data());
         assert(ret);
     }
 
     secp256k1_context_sign = ctx;
 }
 
 void ECC_Stop() {
     secp256k1_context *ctx = secp256k1_context_sign;
     secp256k1_context_sign = nullptr;
 
     if (ctx) {
         secp256k1_context_destroy(ctx);
     }
 }
diff --git a/src/key.h b/src/key.h
index 73e92d555..fc83db7a8 100644
--- a/src/key.h
+++ b/src/key.h
@@ -1,194 +1,197 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017 The Zcash developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_KEY_H
 #define BITCOIN_KEY_H
 
 #include <pubkey.h>
 #include <support/allocators/secure.h>
 #include <uint256.h>
 
 #include <stdexcept>
 #include <vector>
 
 /**
  * secure_allocator is defined in allocators.h
  * CPrivKey is a serialized private key, with all parameters included
  * (SIZE bytes)
  */
 typedef std::vector<uint8_t, secure_allocator<uint8_t>> CPrivKey;
 
 /** An encapsulated secp256k1 private key. */
 class CKey {
 public:
     /**
      * secp256k1:
      */
     static const unsigned int SIZE = 279;
     static const unsigned int COMPRESSED_SIZE = 214;
     /**
      * see www.keylength.com
      * script supports up to 75 for single byte push
      */
     static_assert(SIZE >= COMPRESSED_SIZE,
                   "COMPRESSED_SIZE is larger than SIZE");
 
 private:
     //! Whether this private key is valid. We check for correctness when
     //! modifying the key data, so fValid should always correspond to the actual
     //! state.
     bool fValid;
 
     //! Whether the public key corresponding to this private key is (to be)
     //! compressed.
     bool fCompressed;
 
     //! The actual byte data
     std::vector<uint8_t, secure_allocator<uint8_t>> keydata;
 
     //! Check whether the 32-byte array pointed to by vch is valid keydata.
     static bool Check(const uint8_t *vch);
 
 public:
     //! Construct an invalid private key.
     CKey() : fValid(false), fCompressed(false) {
         // Important: vch must be 32 bytes in length to not break serialization
         keydata.resize(32);
     }
 
     friend bool operator==(const CKey &a, const CKey &b) {
         return a.fCompressed == b.fCompressed && a.size() == b.size() &&
                memcmp(a.keydata.data(), b.keydata.data(), a.size()) == 0;
     }
 
     //! Initialize using begin and end iterators to byte data.
     template <typename T>
     void Set(const T pbegin, const T pend, bool fCompressedIn) {
         if (size_t(pend - pbegin) != keydata.size()) {
             fValid = false;
         } else if (Check(&pbegin[0])) {
             memcpy(keydata.data(), (uint8_t *)&pbegin[0], keydata.size());
             fValid = true;
             fCompressed = fCompressedIn;
         } else {
             fValid = false;
         }
     }
 
     //! Simple read-only vector-like interface.
     unsigned int size() const { return (fValid ? keydata.size() : 0); }
     const uint8_t *begin() const { return keydata.data(); }
     const uint8_t *end() const { return keydata.data() + size(); }
 
     //! Check whether this private key is valid.
     bool IsValid() const { return fValid; }
 
     //! Check whether the public key corresponding to this private key is (to
     //! be) compressed.
     bool IsCompressed() const { return fCompressed; }
 
     //! Generate a new private key using a cryptographic PRNG.
     void MakeNewKey(bool fCompressed);
 
     //! Negate private key
     bool Negate();
 
     /**
      * Convert the private key to a CPrivKey (serialized OpenSSL private key
      * data).
      * This is expensive.
      */
     CPrivKey GetPrivKey() const;
 
     /**
      * Compute the public key from a private key.
      * This is expensive.
      */
     CPubKey GetPubKey() const;
 
     /**
      * Create a DER-serialized ECDSA signature.
      * The test_case parameter tweaks the deterministic nonce.
      */
     bool SignECDSA(const uint256 &hash, std::vector<uint8_t> &vchSig,
                    bool grind = true, uint32_t test_case = 0) const;
 
     /**
      * Create a Schnorr signature.
      * The test_case parameter tweaks the deterministic nonce.
      */
+    bool SignSchnorr(const uint256 &hash,
+                     std::array<uint8_t, CPubKey::SCHNORR_SIZE> &sig,
+                     uint32_t test_case = 0) const;
     bool SignSchnorr(const uint256 &hash, std::vector<uint8_t> &vchSig,
                      uint32_t test_case = 0) const;
 
     /**
      * Create a compact ECDSA signature (65 bytes), which allows reconstructing
      * the used public key.
      * The format is one header byte, followed by two times 32 bytes for the
      * serialized r and s values.
      * The header byte: 0x1B = first key with even y, 0x1C = first key with odd
      * y,
      *                  0x1D = second key with even y, 0x1E = second key with
      * odd y,
      *                  add 0x04 for compressed keys.
      */
     bool SignCompact(const uint256 &hash, std::vector<uint8_t> &vchSig) const;
 
     //! Derive BIP32 child key.
     bool Derive(CKey &keyChild, ChainCode &ccChild, unsigned int nChild,
                 const ChainCode &cc) const;
 
     /**
      * Verify thoroughly whether a private key and a public key match.
      * This is done using a different mechanism than just regenerating it.
      * (An ECDSA signature is created then verified.)
      */
     bool VerifyPubKey(const CPubKey &vchPubKey) const;
 
     //! Load private key and check that public key matches.
     bool Load(const CPrivKey &privkey, const CPubKey &vchPubKey,
               bool fSkipCheck);
 };
 
 struct CExtKey {
     uint8_t nDepth;
     uint8_t vchFingerprint[4];
     unsigned int nChild;
     ChainCode chaincode;
     CKey key;
 
     friend bool operator==(const CExtKey &a, const CExtKey &b) {
         return a.nDepth == b.nDepth &&
                memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0],
                       sizeof(vchFingerprint)) == 0 &&
                a.nChild == b.nChild && a.chaincode == b.chaincode &&
                a.key == b.key;
     }
 
     void Encode(uint8_t code[BIP32_EXTKEY_SIZE]) const;
     void Decode(const uint8_t code[BIP32_EXTKEY_SIZE]);
     bool Derive(CExtKey &out, unsigned int nChild) const;
     CExtPubKey Neuter() const;
     void SetSeed(const uint8_t *seed, unsigned int nSeedLen);
 
     CExtKey() = default;
 };
 
 /**
  * Initialize the elliptic curve support. May not be called twice without
  * calling ECC_Stop first.
  */
 void ECC_Start();
 
 /**
  * Deinitialize the elliptic curve support. No-op if ECC_Start wasn't called
  * first.
  */
 void ECC_Stop();
 
 /** Check that required EC support is available at runtime. */
 bool ECC_InitSanityCheck();
 
 #endif // BITCOIN_KEY_H
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 9799a3820..f9a44a70e 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -1,5289 +1,5286 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <net_processing.h>
 
 #include <addrman.h>
 #include <avalanche/processor.h>
 #include <banman.h>
 #include <blockdb.h>
 #include <blockencodings.h>
 #include <blockfilter.h>
 #include <blockvalidity.h>
 #include <chain.h>
 #include <chainparams.h>
 #include <config.h>
 #include <consensus/validation.h>
 #include <hash.h>
 #include <index/blockfilterindex.h>
 #include <merkleblock.h>
 #include <netbase.h>
 #include <netmessagemaker.h>
 #include <policy/fees.h>
 #include <policy/policy.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
 #include <random.h>
 #include <reverse_iterator.h>
 #include <scheduler.h>
 #include <tinyformat.h>
 #include <txmempool.h>
 #include <util/check.h> // For NDEBUG compile time check
 #include <util/strencodings.h>
 #include <util/system.h>
 #include <validation.h>
 
 #include <memory>
 #include <typeinfo>
 
 /** Expiration time for orphan transactions in seconds */
 static constexpr int64_t ORPHAN_TX_EXPIRE_TIME = 20 * 60;
 /** Minimum time between orphan transactions expire time checks in seconds */
 static constexpr int64_t ORPHAN_TX_EXPIRE_INTERVAL = 5 * 60;
 /** How long to cache transactions in mapRelay for normal relay */
 static constexpr std::chrono::seconds RELAY_TX_CACHE_TIME{15 * 60};
 /**
  * Headers download timeout expressed in microseconds.
  * Timeout = base + per_header * (expected number of headers)
  */
 // 15 minutes
 static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_BASE = 15 * 60 * 1000000;
 // 1ms/header
 static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1000;
 /**
  * Protect at least this many outbound peers from disconnection due to
  * slow/behind headers chain.
  */
 static constexpr int32_t MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT = 4;
 /**
  * Timeout for (unprotected) outbound peers to sync to our chainwork, in
  * seconds.
  */
 // 20 minutes
 static constexpr int64_t CHAIN_SYNC_TIMEOUT = 20 * 60;
 /** How frequently to check for stale tips, in seconds */
 // 10 minutes
 static constexpr int64_t STALE_CHECK_INTERVAL = 10 * 60;
 /**
  * How frequently to check for extra outbound peers and disconnect, in seconds.
  */
 static constexpr int64_t EXTRA_PEER_CHECK_INTERVAL = 45;
 /**
  * Minimum time an outbound-peer-eviction candidate must be connected for, in
  * order to evict, in seconds.
  */
 static constexpr int64_t MINIMUM_CONNECT_TIME = 30;
 /** SHA256("main address relay")[0:8] */
 static constexpr uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL;
 /// Age after which a stale block will no longer be served if requested as
 /// protection against fingerprinting. Set to one month, denominated in seconds.
 static constexpr int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60;
 /// Age after which a block is considered historical for purposes of rate
 /// limiting block relay. Set to one week, denominated in seconds.
 static constexpr int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60;
 /** Maximum number of in-flight transactions from a peer */
 static constexpr int32_t MAX_PEER_TX_IN_FLIGHT = 100;
 /** Maximum number of announced transactions from a peer */
 static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 2 * MAX_INV_SZ;
 /** How many microseconds to delay requesting transactions from inbound peers */
 static constexpr std::chrono::microseconds INBOUND_PEER_TX_DELAY{
     std::chrono::seconds{2}};
 /**
  * How long to wait (in microseconds) before downloading a transaction from an
  * additional peer.
  */
 static constexpr std::chrono::microseconds GETDATA_TX_INTERVAL{
     std::chrono::seconds{60}};
 /**
  * Maximum delay (in microseconds) for transaction requests to avoid biasing
  * some peers over others.
  */
 static constexpr std::chrono::microseconds MAX_GETDATA_RANDOM_DELAY{
     std::chrono::seconds{2}};
 /**
  * How long to wait (in microseconds) before expiring an in-flight getdata
  * request to a peer.
  */
 static constexpr std::chrono::microseconds TX_EXPIRY_INTERVAL{
     GETDATA_TX_INTERVAL * 10};
 static_assert(INBOUND_PEER_TX_DELAY >= MAX_GETDATA_RANDOM_DELAY,
               "To preserve security, MAX_GETDATA_RANDOM_DELAY should not "
               "exceed INBOUND_PEER_DELAY");
 /**
  * Limit to avoid sending big packets. Not used in processing incoming GETDATA
  * for compatibility.
  */
 static const unsigned int MAX_GETDATA_SZ = 1000;
 
 /// How many non standard orphan do we consider from a node before ignoring it.
 static constexpr uint32_t MAX_NON_STANDARD_ORPHAN_PER_NODE = 5;
 
 struct COrphanTx {
     // When modifying, adapt the copy of this definition in tests/DoS_tests.
     CTransactionRef tx;
     NodeId fromPeer;
     int64_t nTimeExpire;
     size_t list_pos;
 };
 
 RecursiveMutex g_cs_orphans;
 std::map<TxId, COrphanTx> mapOrphanTransactions GUARDED_BY(g_cs_orphans);
 
 void EraseOrphansFor(NodeId peer);
 
 /**
  * Average delay between local address broadcasts.
  */
 static constexpr std::chrono::hours AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24};
 /**
  * Average delay between peer address broadcasts.
  */
 static const std::chrono::seconds AVG_ADDRESS_BROADCAST_INTERVAL{30};
 /**
  * Average delay between trickled inventory transmissions in seconds.
  * Blocks and whitelisted receivers bypass this, outbound peers get half this
  * delay.
  */
 static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5;
 /**
  * Maximum number of inventory items to send per transmission.
  * Limits the impact of low-fee transaction floods.
  */
 static constexpr unsigned int INVENTORY_BROADCAST_MAX_PER_MB =
     7 * INVENTORY_BROADCAST_INTERVAL;
 /**
  * Average delay between feefilter broadcasts in seconds.
  */
 static constexpr unsigned int AVG_FEEFILTER_BROADCAST_INTERVAL = 10 * 60;
 /**
  * Maximum feefilter broadcast delay after significant change.
  */
 static constexpr unsigned int MAX_FEEFILTER_CHANGE_DELAY = 5 * 60;
 /**
  * Maximum number of compact filters that may be requested with one
  * getcfilters. See BIP 157.
  */
 static constexpr uint32_t MAX_GETCFILTERS_SIZE = 1000;
 /**
  * Maximum number of cf hashes that may be requested with one getcfheaders. See
  * BIP 157.
  */
 static constexpr uint32_t MAX_GETCFHEADERS_SIZE = 2000;
 
 // Internal stuff
 namespace {
 /** Number of nodes with fSyncStarted. */
 int nSyncStarted GUARDED_BY(cs_main) = 0;
 
 /**
  * Sources of received blocks, saved to be able to punish them when processing
  * happens afterwards.
  * Set mapBlockSource[hash].second to false if the node should not be punished
  * if the block is invalid.
  */
 std::map<BlockHash, std::pair<NodeId, bool>> mapBlockSource GUARDED_BY(cs_main);
 
 /**
  * Filter for transactions that were recently rejected by AcceptToMemoryPool.
  * These are not rerequested until the chain tip changes, at which point the
  * entire filter is reset.
  *
  * Without this filter we'd be re-requesting txs from each of our peers,
  * increasing bandwidth consumption considerably. For instance, with 100 peers,
  * half of which relay a tx we don't accept, that might be a 50x bandwidth
  * increase. A flooding attacker attempting to roll-over the filter using
  * minimum-sized, 60byte, transactions might manage to send 1000/sec if we have
  * fast peers, so we pick 120,000 to give our peers a two minute window to send
  * invs to us.
  *
  * Decreasing the false positive rate is fairly cheap, so we pick one in a
  * million to make it highly unlikely for users to have issues with this filter.
  *
  * Memory used: 1.3 MB
  */
 std::unique_ptr<CRollingBloomFilter> recentRejects GUARDED_BY(cs_main);
 uint256 hashRecentRejectsChainTip GUARDED_BY(cs_main);
 
 /**
  * Blocks that are in flight, and that are in the queue to be downloaded.
  */
 struct QueuedBlock {
     BlockHash hash;
     //! Optional.
     const CBlockIndex *pindex;
     //! Whether this block has validated headers at the time of request.
     bool fValidatedHeaders;
     //! Optional, used for CMPCTBLOCK downloads
     std::unique_ptr<PartiallyDownloadedBlock> partialBlock;
 };
 std::map<BlockHash, std::pair<NodeId, std::list<QueuedBlock>::iterator>>
     mapBlocksInFlight GUARDED_BY(cs_main);
 
 /** Stack of nodes which we have set to announce using compact blocks */
 std::list<NodeId> lNodesAnnouncingHeaderAndIDs GUARDED_BY(cs_main);
 
 /** Number of preferable block download peers. */
 int nPreferredDownload GUARDED_BY(cs_main) = 0;
 
 /** Number of peers from which we're downloading blocks. */
 int nPeersWithValidatedDownloads GUARDED_BY(cs_main) = 0;
 
 /** Number of outbound peers with m_chain_sync.m_protect. */
 int g_outbound_peers_with_protect_from_disconnect GUARDED_BY(cs_main) = 0;
 
 /** When our tip was last updated. */
 std::atomic<int64_t> g_last_tip_update(0);
 
 /** Relay map. */
 typedef std::map<uint256, CTransactionRef> MapRelay;
 MapRelay mapRelay GUARDED_BY(cs_main);
 /**
  * Expiration-time ordered list of (expire time, relay map entry) pairs,
  * protected by cs_main).
  */
 std::deque<std::pair<int64_t, MapRelay::iterator>>
     vRelayExpiration GUARDED_BY(cs_main);
 
 struct IteratorComparator {
     template <typename I> bool operator()(const I &a, const I &b) const {
         return &(*a) < &(*b);
     }
 };
 std::map<COutPoint,
          std::set<std::map<TxId, COrphanTx>::iterator, IteratorComparator>>
     mapOrphanTransactionsByPrev GUARDED_BY(g_cs_orphans);
 
 //! For random eviction
 std::vector<std::map<TxId, COrphanTx>::iterator>
     g_orphan_list GUARDED_BY(g_cs_orphans);
 
 static size_t vExtraTxnForCompactIt GUARDED_BY(g_cs_orphans) = 0;
 static std::vector<std::pair<TxHash, CTransactionRef>>
     vExtraTxnForCompact GUARDED_BY(g_cs_orphans);
 } // namespace
 
 namespace {
 /**
  * Maintain validation-specific state about nodes, protected by cs_main, instead
  * by CNode's own locks. This simplifies asynchronous operation, where
  * processing of incoming data is done after the ProcessMessage call returns,
  * and we're no longer holding the node's locks.
  */
 struct CNodeState {
     //! The peer's address
     const CService address;
     //! Whether we have a fully established connection.
     bool fCurrentlyConnected;
     //! Accumulated misbehaviour score for this peer.
     int nMisbehavior;
     //! Whether this peer should be disconnected and marked as discouraged
     //! (unless whitelisted with noban).
     bool m_should_discourage;
     //! String name of this peer (debugging/logging purposes).
     const std::string name;
     //! The best known block we know this peer has announced.
     const CBlockIndex *pindexBestKnownBlock;
     //! The hash of the last unknown block this peer has announced.
     BlockHash hashLastUnknownBlock;
     //! The last full block we both have.
     const CBlockIndex *pindexLastCommonBlock;
     //! The best header we have sent our peer.
     const CBlockIndex *pindexBestHeaderSent;
     //! Length of current-streak of unconnecting headers announcements
     int nUnconnectingHeaders;
     //! Whether we've started headers synchronization with this peer.
     bool fSyncStarted;
     //! When to potentially disconnect peer for stalling headers download
     int64_t nHeadersSyncTimeout;
     //! Since when we're stalling block download progress (in microseconds), or
     //! 0.
     int64_t nStallingSince;
     std::list<QueuedBlock> vBlocksInFlight;
     //! When the first entry in vBlocksInFlight started downloading. Don't care
     //! when vBlocksInFlight is empty.
     int64_t nDownloadingSince;
     int nBlocksInFlight;
     int nBlocksInFlightValidHeaders;
     //! Whether we consider this a preferred download peer.
     bool fPreferredDownload;
     //! Whether this peer wants invs or headers (when possible) for block
     //! announcements.
     bool fPreferHeaders;
     //! Whether this peer wants invs or cmpctblocks (when possible) for block
     //! announcements.
     bool fPreferHeaderAndIDs;
     /**
      * Whether this peer will send us cmpctblocks if we request them.
      * This is not used to gate request logic, as we really only care about
      * fSupportsDesiredCmpctVersion, but is used as a flag to "lock in" the
      * version of compact blocks we send.
      */
     bool fProvidesHeaderAndIDs;
     /**
      * If we've announced NODE_WITNESS to this peer: whether the peer sends
      * witnesses in cmpctblocks/blocktxns, otherwise: whether this peer sends
      * non-witnesses in cmpctblocks/blocktxns.
      */
     bool fSupportsDesiredCmpctVersion;
 
     /**
      * State used to enforce CHAIN_SYNC_TIMEOUT
      * Only in effect for outbound, non-manual, full-relay connections, with
      * m_protect == false
      * Algorithm: if a peer's best known block has less work than our tip, set
      * a timeout CHAIN_SYNC_TIMEOUT seconds in the future:
      *   - If at timeout their best known block now has more work than our tip
      * when the timeout was set, then either reset the timeout or clear it
      * (after comparing against our current tip's work)
      *   - If at timeout their best known block still has less work than our tip
      * did when the timeout was set, then send a getheaders message, and set a
      * shorter timeout, HEADERS_RESPONSE_TIME seconds in future. If their best
      * known block is still behind when that new timeout is reached, disconnect.
      */
     struct ChainSyncTimeoutState {
         //! A timeout used for checking whether our peer has sufficiently
         //! synced.
         int64_t m_timeout;
         //! A header with the work we require on our peer's chain.
         const CBlockIndex *m_work_header;
         //! After timeout is reached, set to true after sending getheaders.
         bool m_sent_getheaders;
         //! Whether this peer is protected from disconnection due to a bad/slow
         //! chain.
         bool m_protect;
     };
 
     ChainSyncTimeoutState m_chain_sync;
 
     //! Time of last new block announcement
     int64_t m_last_block_announcement;
 
     /*
      * State associated with transaction download.
      *
      * Tx download algorithm:
      *
      *   When inv comes in, queue up (process_time, txid) inside the peer's
      *   CNodeState (m_tx_process_time) as long as m_tx_announced for the peer
      *   isn't too big (MAX_PEER_TX_ANNOUNCEMENTS).
      *
      *   The process_time for a transaction is set to nNow for outbound peers,
      *   nNow + 2 seconds for inbound peers. This is the time at which we'll
      *   consider trying to request the transaction from the peer in
      *   SendMessages(). The delay for inbound peers is to allow outbound peers
      *   a chance to announce before we request from inbound peers, to prevent
      *   an adversary from using inbound connections to blind us to a
      *   transaction (InvBlock).
      *
      *   When we call SendMessages() for a given peer,
      *   we will loop over the transactions in m_tx_process_time, looking
      *   at the transactions whose process_time <= nNow. We'll request each
      *   such transaction that we don't have already and that hasn't been
      *   requested from another peer recently, up until we hit the
      *   MAX_PEER_TX_IN_FLIGHT limit for the peer. Then we'll update
      *   g_already_asked_for for each requested txid, storing the time of the
      *   GETDATA request. We use g_already_asked_for to coordinate transaction
      *   requests amongst our peers.
      *
      *   For transactions that we still need but we have already recently
      *   requested from some other peer, we'll reinsert (process_time, txid)
      *   back into the peer's m_tx_process_time at the point in the future at
      *   which the most recent GETDATA request would time out (ie
      *   GETDATA_TX_INTERVAL + the request time stored in g_already_asked_for).
      *   We add an additional delay for inbound peers, again to prefer
      *   attempting download from outbound peers first.
      *   We also add an extra small random delay up to 2 seconds
      *   to avoid biasing some peers over others. (e.g., due to fixed ordering
      *   of peer processing in ThreadMessageHandler).
      *
      *   When we receive a transaction from a peer, we remove the txid from the
      *   peer's m_tx_in_flight set and from their recently announced set
      *   (m_tx_announced).  We also clear g_already_asked_for for that entry, so
      *   that if somehow the transaction is not accepted but also not added to
      *   the reject filter, then we will eventually redownload from other
      *   peers.
      */
     struct TxDownloadState {
         /**
          * Track when to attempt download of announced transactions (process
          * time in micros -> txid)
          */
         std::multimap<std::chrono::microseconds, TxId> m_tx_process_time;
 
         //! Store all the transactions a peer has recently announced
         std::set<TxId> m_tx_announced;
 
         //! Store transactions which were requested by us, with timestamp
         std::map<TxId, std::chrono::microseconds> m_tx_in_flight;
 
         //! Periodically check for stuck getdata requests
         std::chrono::microseconds m_check_expiry_timer{0};
     };
 
     TxDownloadState m_tx_download;
 
     struct AvalancheState {
         std::chrono::time_point<std::chrono::steady_clock> last_poll;
     };
 
     AvalancheState m_avalanche_state;
 
     //! Whether this peer is an inbound connection
     bool m_is_inbound;
 
     //! Whether this peer is a manual connection
     bool m_is_manual_connection;
 
     CNodeState(CAddress addrIn, std::string addrNameIn, bool is_inbound,
                bool is_manual)
         : address(addrIn), name(std::move(addrNameIn)),
           m_is_inbound(is_inbound), m_is_manual_connection(is_manual) {
         fCurrentlyConnected = false;
         nMisbehavior = 0;
         m_should_discourage = false;
         pindexBestKnownBlock = nullptr;
         hashLastUnknownBlock = BlockHash();
         pindexLastCommonBlock = nullptr;
         pindexBestHeaderSent = nullptr;
         nUnconnectingHeaders = 0;
         fSyncStarted = false;
         nHeadersSyncTimeout = 0;
         nStallingSince = 0;
         nDownloadingSince = 0;
         nBlocksInFlight = 0;
         nBlocksInFlightValidHeaders = 0;
         fPreferredDownload = false;
         fPreferHeaders = false;
         fPreferHeaderAndIDs = false;
         fProvidesHeaderAndIDs = false;
         fSupportsDesiredCmpctVersion = false;
         m_chain_sync = {0, nullptr, false, false};
         m_last_block_announcement = 0;
     }
 };
 
 // Keeps track of the time (in microseconds) when transactions were requested
 // last time
 limitedmap<TxId, std::chrono::microseconds>
     g_already_asked_for GUARDED_BY(cs_main)(MAX_INV_SZ);
 
 /** Map maintaining per-node state. */
 static std::map<NodeId, CNodeState> mapNodeState GUARDED_BY(cs_main);
 
 static CNodeState *State(NodeId pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     std::map<NodeId, CNodeState>::iterator it = mapNodeState.find(pnode);
     if (it == mapNodeState.end()) {
         return nullptr;
     }
 
     return &it->second;
 }
 
 static void UpdatePreferredDownload(const CNode &node, CNodeState *state)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     nPreferredDownload -= state->fPreferredDownload;
 
     // Whether this node should be marked as a preferred download node.
     state->fPreferredDownload =
         (!node.fInbound || node.HasPermission(PF_NOBAN)) && !node.fOneShot &&
         !node.fClient;
 
     nPreferredDownload += state->fPreferredDownload;
 }
 
 static void PushNodeVersion(const Config &config, CNode &pnode,
                             CConnman &connman, int64_t nTime) {
     // Note that pnode.GetLocalServices() is a reflection of the local
     // services we were offering when the CNode object was created for this
     // peer.
     ServiceFlags nLocalNodeServices = pnode.GetLocalServices();
     uint64_t nonce = pnode.GetLocalNonce();
     int nNodeStartingHeight = pnode.GetMyStartingHeight();
     NodeId nodeid = pnode.GetId();
     CAddress addr = pnode.addr;
 
     CAddress addrYou = (addr.IsRoutable() && !IsProxy(addr)
                             ? addr
                             : CAddress(CService(), addr.nServices));
     CAddress addrMe = CAddress(CService(), nLocalNodeServices);
 
     connman.PushMessage(
         &pnode, CNetMsgMaker(INIT_PROTO_VERSION)
                     .Make(NetMsgType::VERSION, PROTOCOL_VERSION,
                           uint64_t(nLocalNodeServices), nTime, addrYou, addrMe,
                           nonce, userAgent(config), nNodeStartingHeight,
                           ::g_relay_txes && pnode.m_tx_relay != nullptr));
 
     if (fLogIPs) {
         LogPrint(BCLog::NET,
                  "send version message: version %d, blocks=%d, us=%s, them=%s, "
                  "peer=%d\n",
                  PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(),
                  addrYou.ToString(), nodeid);
     } else {
         LogPrint(
             BCLog::NET,
             "send version message: version %d, blocks=%d, us=%s, peer=%d\n",
             PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(), nodeid);
     }
     LogPrint(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid);
 }
 
 // Returns a bool indicating whether we requested this block.
 // Also used if a block was /not/ received and timed out or started with another
 // peer.
 static bool MarkBlockAsReceived(const BlockHash &hash)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     std::map<BlockHash,
              std::pair<NodeId, std::list<QueuedBlock>::iterator>>::iterator
         itInFlight = mapBlocksInFlight.find(hash);
     if (itInFlight != mapBlocksInFlight.end()) {
         CNodeState *state = State(itInFlight->second.first);
         assert(state != nullptr);
         state->nBlocksInFlightValidHeaders -=
             itInFlight->second.second->fValidatedHeaders;
         if (state->nBlocksInFlightValidHeaders == 0 &&
             itInFlight->second.second->fValidatedHeaders) {
             // Last validated block on the queue was received.
             nPeersWithValidatedDownloads--;
         }
         if (state->vBlocksInFlight.begin() == itInFlight->second.second) {
             // First block on the queue was received, update the start download
             // time for the next one
             state->nDownloadingSince =
                 std::max(state->nDownloadingSince, GetTimeMicros());
         }
         state->vBlocksInFlight.erase(itInFlight->second.second);
         state->nBlocksInFlight--;
         state->nStallingSince = 0;
         mapBlocksInFlight.erase(itInFlight);
         return true;
     }
 
     return false;
 }
 
 // returns false, still setting pit, if the block was already in flight from the
 // same peer
 // pit will only be valid as long as the same cs_main lock is being held.
 static bool
 MarkBlockAsInFlight(const Config &config, NodeId nodeid, const BlockHash &hash,
                     const Consensus::Params &consensusParams,
                     const CBlockIndex *pindex = nullptr,
                     std::list<QueuedBlock>::iterator **pit = nullptr)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     // Short-circuit most stuff in case it is from the same node.
     std::map<BlockHash,
              std::pair<NodeId, std::list<QueuedBlock>::iterator>>::iterator
         itInFlight = mapBlocksInFlight.find(hash);
     if (itInFlight != mapBlocksInFlight.end() &&
         itInFlight->second.first == nodeid) {
         if (pit) {
             *pit = &itInFlight->second.second;
         }
         return false;
     }
 
     // Make sure it's not listed somewhere already.
     MarkBlockAsReceived(hash);
 
     std::list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(
         state->vBlocksInFlight.end(),
         {hash, pindex, pindex != nullptr,
          std::unique_ptr<PartiallyDownloadedBlock>(
              pit ? new PartiallyDownloadedBlock(config, &g_mempool)
                  : nullptr)});
     state->nBlocksInFlight++;
     state->nBlocksInFlightValidHeaders += it->fValidatedHeaders;
     if (state->nBlocksInFlight == 1) {
         // We're starting a block download (batch) from this peer.
         state->nDownloadingSince = GetTimeMicros();
     }
 
     if (state->nBlocksInFlightValidHeaders == 1 && pindex != nullptr) {
         nPeersWithValidatedDownloads++;
     }
 
     itInFlight = mapBlocksInFlight
                      .insert(std::make_pair(hash, std::make_pair(nodeid, it)))
                      .first;
 
     if (pit) {
         *pit = &itInFlight->second.second;
     }
 
     return true;
 }
 
 /** Check whether the last unknown block a peer advertised is not yet known. */
 static void ProcessBlockAvailability(NodeId nodeid)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     if (!state->hashLastUnknownBlock.IsNull()) {
         const CBlockIndex *pindex =
             LookupBlockIndex(state->hashLastUnknownBlock);
         if (pindex && pindex->nChainWork > 0) {
             if (state->pindexBestKnownBlock == nullptr ||
                 pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) {
                 state->pindexBestKnownBlock = pindex;
             }
             state->hashLastUnknownBlock.SetNull();
         }
     }
 }
 
 /** Update tracking information about which blocks a peer is assumed to have. */
 static void UpdateBlockAvailability(NodeId nodeid, const BlockHash &hash)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     ProcessBlockAvailability(nodeid);
 
     const CBlockIndex *pindex = LookupBlockIndex(hash);
     if (pindex && pindex->nChainWork > 0) {
         // An actually better block was announced.
         if (state->pindexBestKnownBlock == nullptr ||
             pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) {
             state->pindexBestKnownBlock = pindex;
         }
     } else {
         // An unknown block was announced; just assume that the latest one is
         // the best one.
         state->hashLastUnknownBlock = hash;
     }
 }
 
 /**
  * When a peer sends us a valid block, instruct it to announce blocks to us
  * using CMPCTBLOCK if possible by adding its nodeid to the end of
  * lNodesAnnouncingHeaderAndIDs, and keeping that list under a certain size by
  * removing the first element if necessary.
  */
 static void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid,
                                                  CConnman &connman)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     CNodeState *nodestate = State(nodeid);
     if (!nodestate) {
         LogPrint(BCLog::NET, "node state unavailable: peer=%d\n", nodeid);
         return;
     }
     if (!nodestate->fProvidesHeaderAndIDs) {
         return;
     }
     for (std::list<NodeId>::iterator it = lNodesAnnouncingHeaderAndIDs.begin();
          it != lNodesAnnouncingHeaderAndIDs.end(); it++) {
         if (*it == nodeid) {
             lNodesAnnouncingHeaderAndIDs.erase(it);
             lNodesAnnouncingHeaderAndIDs.push_back(nodeid);
             return;
         }
     }
     connman.ForNode(nodeid, [&connman](CNode *pfrom) {
         AssertLockHeld(cs_main);
         uint64_t nCMPCTBLOCKVersion = 1;
         if (lNodesAnnouncingHeaderAndIDs.size() >= 3) {
             // As per BIP152, we only get 3 of our peers to announce
             // blocks using compact encodings.
             connman.ForNode(
                 lNodesAnnouncingHeaderAndIDs.front(),
                 [&connman, nCMPCTBLOCKVersion](CNode *pnodeStop) {
                     AssertLockHeld(cs_main);
                     connman.PushMessage(
                         pnodeStop, CNetMsgMaker(pnodeStop->GetSendVersion())
                                        .Make(NetMsgType::SENDCMPCT,
                                              /*fAnnounceUsingCMPCTBLOCK=*/false,
                                              nCMPCTBLOCKVersion));
                     return true;
                 });
             lNodesAnnouncingHeaderAndIDs.pop_front();
         }
         connman.PushMessage(pfrom, CNetMsgMaker(pfrom->GetSendVersion())
                                        .Make(NetMsgType::SENDCMPCT,
                                              /*fAnnounceUsingCMPCTBLOCK=*/true,
                                              nCMPCTBLOCKVersion));
         lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId());
         return true;
     });
 }
 
 static bool TipMayBeStale(const Consensus::Params &consensusParams)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     if (g_last_tip_update == 0) {
         g_last_tip_update = GetTime();
     }
     return g_last_tip_update <
                GetTime() - consensusParams.nPowTargetSpacing * 3 &&
            mapBlocksInFlight.empty();
 }
 
 static bool CanDirectFetch(const Consensus::Params &consensusParams)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     return ::ChainActive().Tip()->GetBlockTime() >
            GetAdjustedTime() - consensusParams.nPowTargetSpacing * 20;
 }
 
 static bool PeerHasHeader(CNodeState *state, const CBlockIndex *pindex)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     if (state->pindexBestKnownBlock &&
         pindex == state->pindexBestKnownBlock->GetAncestor(pindex->nHeight)) {
         return true;
     }
     if (state->pindexBestHeaderSent &&
         pindex == state->pindexBestHeaderSent->GetAncestor(pindex->nHeight)) {
         return true;
     }
     return false;
 }
 
 /**
  * Update pindexLastCommonBlock and add not-in-flight missing successors to
  * vBlocks, until it has at most count entries.
  */
 static void FindNextBlocksToDownload(NodeId nodeid, unsigned int count,
                                      std::vector<const CBlockIndex *> &vBlocks,
                                      NodeId &nodeStaller,
                                      const Consensus::Params &consensusParams)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     if (count == 0) {
         return;
     }
 
     vBlocks.reserve(vBlocks.size() + count);
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     // Make sure pindexBestKnownBlock is up to date, we'll need it.
     ProcessBlockAvailability(nodeid);
 
     if (state->pindexBestKnownBlock == nullptr ||
         state->pindexBestKnownBlock->nChainWork <
             ::ChainActive().Tip()->nChainWork ||
         state->pindexBestKnownBlock->nChainWork < nMinimumChainWork) {
         // This peer has nothing interesting.
         return;
     }
 
     if (state->pindexLastCommonBlock == nullptr) {
         // Bootstrap quickly by guessing a parent of our best tip is the forking
         // point. Guessing wrong in either direction is not a problem.
         state->pindexLastCommonBlock = ::ChainActive()[std::min(
             state->pindexBestKnownBlock->nHeight, ::ChainActive().Height())];
     }
 
     // If the peer reorganized, our previous pindexLastCommonBlock may not be an
     // ancestor of its current tip anymore. Go back enough to fix that.
     state->pindexLastCommonBlock = LastCommonAncestor(
         state->pindexLastCommonBlock, state->pindexBestKnownBlock);
     if (state->pindexLastCommonBlock == state->pindexBestKnownBlock) {
         return;
     }
 
     std::vector<const CBlockIndex *> vToFetch;
     const CBlockIndex *pindexWalk = state->pindexLastCommonBlock;
     // Never fetch further than the best block we know the peer has, or more
     // than BLOCK_DOWNLOAD_WINDOW + 1 beyond the last linked block we have in
     // common with this peer. The +1 is so we can detect stalling, namely if we
     // would be able to download that next block if the window were 1 larger.
     int nWindowEnd =
         state->pindexLastCommonBlock->nHeight + BLOCK_DOWNLOAD_WINDOW;
     int nMaxHeight =
         std::min<int>(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1);
     NodeId waitingfor = -1;
     while (pindexWalk->nHeight < nMaxHeight) {
         // Read up to 128 (or more, if more blocks than that are needed)
         // successors of pindexWalk (towards pindexBestKnownBlock) into
         // vToFetch. We fetch 128, because CBlockIndex::GetAncestor may be as
         // expensive as iterating over ~100 CBlockIndex* entries anyway.
         int nToFetch = std::min(nMaxHeight - pindexWalk->nHeight,
                                 std::max<int>(count - vBlocks.size(), 128));
         vToFetch.resize(nToFetch);
         pindexWalk = state->pindexBestKnownBlock->GetAncestor(
             pindexWalk->nHeight + nToFetch);
         vToFetch[nToFetch - 1] = pindexWalk;
         for (unsigned int i = nToFetch - 1; i > 0; i--) {
             vToFetch[i - 1] = vToFetch[i]->pprev;
         }
 
         // Iterate over those blocks in vToFetch (in forward direction), adding
         // the ones that are not yet downloaded and not in flight to vBlocks. In
         // the meantime, update pindexLastCommonBlock as long as all ancestors
         // are already downloaded, or if it's already part of our chain (and
         // therefore don't need it even if pruned).
         for (const CBlockIndex *pindex : vToFetch) {
             if (!pindex->IsValid(BlockValidity::TREE)) {
                 // We consider the chain that this peer is on invalid.
                 return;
             }
             if (pindex->nStatus.hasData() || ::ChainActive().Contains(pindex)) {
                 if (pindex->HaveTxsDownloaded()) {
                     state->pindexLastCommonBlock = pindex;
                 }
             } else if (mapBlocksInFlight.count(pindex->GetBlockHash()) == 0) {
                 // The block is not already downloaded, and not yet in flight.
                 if (pindex->nHeight > nWindowEnd) {
                     // We reached the end of the window.
                     if (vBlocks.size() == 0 && waitingfor != nodeid) {
                         // We aren't able to fetch anything, but we would be if
                         // the download window was one larger.
                         nodeStaller = waitingfor;
                     }
                     return;
                 }
                 vBlocks.push_back(pindex);
                 if (vBlocks.size() == count) {
                     return;
                 }
             } else if (waitingfor == -1) {
                 // This is the first already-in-flight block.
                 waitingfor = mapBlocksInFlight[pindex->GetBlockHash()].first;
             }
         }
     }
 }
 
 void EraseTxRequest(const TxId &txid) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     g_already_asked_for.erase(txid);
 }
 
 std::chrono::microseconds GetTxRequestTime(const TxId &txid)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     auto it = g_already_asked_for.find(txid);
     if (it != g_already_asked_for.end()) {
         return it->second;
     }
     return {};
 }
 
 void UpdateTxRequestTime(const TxId &txid,
                          std::chrono::microseconds request_time)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     auto it = g_already_asked_for.find(txid);
     if (it == g_already_asked_for.end()) {
         g_already_asked_for.insert(std::make_pair(txid, request_time));
     } else {
         g_already_asked_for.update(it, request_time);
     }
 }
 
 std::chrono::microseconds
 CalculateTxGetDataTime(const TxId &txid, std::chrono::microseconds current_time,
                        bool use_inbound_delay)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     std::chrono::microseconds process_time;
     const auto last_request_time = GetTxRequestTime(txid);
     // First time requesting this tx
     if (last_request_time.count() == 0) {
         process_time = current_time;
     } else {
         // Randomize the delay to avoid biasing some peers over others (such as
         // due to fixed ordering of peer processing in ThreadMessageHandler)
         process_time = last_request_time + GETDATA_TX_INTERVAL +
                        GetRandMicros(MAX_GETDATA_RANDOM_DELAY);
     }
 
     // We delay processing announcements from inbound peers
     if (use_inbound_delay) {
         process_time += INBOUND_PEER_TX_DELAY;
     }
 
     return process_time;
 }
 
 void RequestTx(CNodeState *state, const TxId &txid,
                std::chrono::microseconds current_time)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     CNodeState::TxDownloadState &peer_download_state = state->m_tx_download;
     if (peer_download_state.m_tx_announced.size() >=
             MAX_PEER_TX_ANNOUNCEMENTS ||
         peer_download_state.m_tx_process_time.size() >=
             MAX_PEER_TX_ANNOUNCEMENTS ||
         peer_download_state.m_tx_announced.count(txid)) {
         // Too many queued announcements from this peer, or we already have
         // this announcement
         return;
     }
     peer_download_state.m_tx_announced.insert(txid);
 
     // Calculate the time to try requesting this transaction. Use
     // fPreferredDownload as a proxy for outbound peers.
     const auto process_time =
         CalculateTxGetDataTime(txid, current_time, !state->fPreferredDownload);
 
     peer_download_state.m_tx_process_time.emplace(process_time, txid);
 }
 
 } // namespace
 
 // This function is used for testing the stale tip eviction logic, see
 // denialofservice_tests.cpp
 void UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds) {
     LOCK(cs_main);
     CNodeState *state = State(node);
     if (state) {
         state->m_last_block_announcement = time_in_seconds;
     }
 }
 
 // Returns true for outbound peers, excluding manual connections, feelers, and
 // one-shots.
 static bool IsOutboundDisconnectionCandidate(const CNode &node) {
     return !(node.fInbound || node.m_manual_connection || node.fFeeler ||
              node.fOneShot);
 }
 
 void PeerLogicValidation::InitializeNode(const Config &config, CNode *pnode) {
     CAddress addr = pnode->addr;
     std::string addrName = pnode->GetAddrName();
     NodeId nodeid = pnode->GetId();
     {
         LOCK(cs_main);
         mapNodeState.emplace_hint(
             mapNodeState.end(), std::piecewise_construct,
             std::forward_as_tuple(nodeid),
             std::forward_as_tuple(addr, std::move(addrName), pnode->fInbound,
                                   pnode->m_manual_connection));
     }
     if (!pnode->fInbound) {
         PushNodeVersion(config, *pnode, *connman, GetTime());
     }
 }
 
 void PeerLogicValidation::FinalizeNode(const Config &config, NodeId nodeid,
                                        bool &fUpdateConnectionTime) {
     fUpdateConnectionTime = false;
     LOCK(cs_main);
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     if (state->fSyncStarted) {
         nSyncStarted--;
     }
 
     if (state->nMisbehavior == 0 && state->fCurrentlyConnected) {
         fUpdateConnectionTime = true;
     }
 
     for (const QueuedBlock &entry : state->vBlocksInFlight) {
         mapBlocksInFlight.erase(entry.hash);
     }
     EraseOrphansFor(nodeid);
     nPreferredDownload -= state->fPreferredDownload;
     nPeersWithValidatedDownloads -= (state->nBlocksInFlightValidHeaders != 0);
     assert(nPeersWithValidatedDownloads >= 0);
     g_outbound_peers_with_protect_from_disconnect -=
         state->m_chain_sync.m_protect;
     assert(g_outbound_peers_with_protect_from_disconnect >= 0);
 
     mapNodeState.erase(nodeid);
 
     if (mapNodeState.empty()) {
         // Do a consistency check after the last peer is removed.
         assert(mapBlocksInFlight.empty());
         assert(nPreferredDownload == 0);
         assert(nPeersWithValidatedDownloads == 0);
         assert(g_outbound_peers_with_protect_from_disconnect == 0);
     }
     LogPrint(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid);
 }
 
 bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) {
     LOCK(cs_main);
     CNodeState *state = State(nodeid);
     if (state == nullptr) {
         return false;
     }
     stats.nMisbehavior = state->nMisbehavior;
     stats.nSyncHeight =
         state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1;
     stats.nCommonHeight = state->pindexLastCommonBlock
                               ? state->pindexLastCommonBlock->nHeight
                               : -1;
     for (const QueuedBlock &queue : state->vBlocksInFlight) {
         if (queue.pindex) {
             stats.vHeightInFlight.push_back(queue.pindex->nHeight);
         }
     }
     return true;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // mapOrphanTransactions
 //
 
 static void AddToCompactExtraTransactions(const CTransactionRef &tx)
     EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) {
     size_t max_extra_txn = gArgs.GetArg("-blockreconstructionextratxn",
                                         DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN);
     if (max_extra_txn <= 0) {
         return;
     }
 
     if (!vExtraTxnForCompact.size()) {
         vExtraTxnForCompact.resize(max_extra_txn);
     }
 
     vExtraTxnForCompact[vExtraTxnForCompactIt] =
         std::make_pair(tx->GetHash(), tx);
     vExtraTxnForCompactIt = (vExtraTxnForCompactIt + 1) % max_extra_txn;
 }
 
 bool AddOrphanTx(const CTransactionRef &tx, NodeId peer)
     EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) {
     const TxId &txid = tx->GetId();
     if (mapOrphanTransactions.count(txid)) {
         return false;
     }
 
     // Ignore big transactions, to avoid a send-big-orphans memory exhaustion
     // attack. If a peer has a legitimate large transaction with a missing
     // parent then we assume it will rebroadcast it later, after the parent
     // transaction(s) have been mined or received.
     // 100 orphans, each of which is at most 100,000 bytes big is at most 10
     // megabytes of orphans and somewhat more byprev index (in the worst case):
     unsigned int sz = tx->GetTotalSize();
     if (sz > MAX_STANDARD_TX_SIZE) {
         LogPrint(BCLog::MEMPOOL,
                  "ignoring large orphan tx (size: %u, hash: %s)\n", sz,
                  txid.ToString());
         return false;
     }
 
     auto ret = mapOrphanTransactions.emplace(
         txid, COrphanTx{tx, peer, GetTime() + ORPHAN_TX_EXPIRE_TIME,
                         g_orphan_list.size()});
     assert(ret.second);
     g_orphan_list.push_back(ret.first);
     for (const CTxIn &txin : tx->vin) {
         mapOrphanTransactionsByPrev[txin.prevout].insert(ret.first);
     }
 
     AddToCompactExtraTransactions(tx);
 
     LogPrint(BCLog::MEMPOOL, "stored orphan tx %s (mapsz %u outsz %u)\n",
              txid.ToString(), mapOrphanTransactions.size(),
              mapOrphanTransactionsByPrev.size());
     return true;
 }
 
 static int EraseOrphanTx(const TxId id) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) {
     const auto it = mapOrphanTransactions.find(id);
     if (it == mapOrphanTransactions.end()) {
         return 0;
     }
     for (const CTxIn &txin : it->second.tx->vin) {
         const auto itPrev = mapOrphanTransactionsByPrev.find(txin.prevout);
         if (itPrev == mapOrphanTransactionsByPrev.end()) {
             continue;
         }
         itPrev->second.erase(it);
         if (itPrev->second.empty()) {
             mapOrphanTransactionsByPrev.erase(itPrev);
         }
     }
 
     size_t old_pos = it->second.list_pos;
     assert(g_orphan_list[old_pos] == it);
     if (old_pos + 1 != g_orphan_list.size()) {
         // Unless we're deleting the last entry in g_orphan_list, move the last
         // entry to the position we're deleting.
         auto it_last = g_orphan_list.back();
         g_orphan_list[old_pos] = it_last;
         it_last->second.list_pos = old_pos;
     }
     g_orphan_list.pop_back();
 
     mapOrphanTransactions.erase(it);
     return 1;
 }
 
 void EraseOrphansFor(NodeId peer) {
     LOCK(g_cs_orphans);
     int nErased = 0;
     auto iter = mapOrphanTransactions.begin();
     while (iter != mapOrphanTransactions.end()) {
         // Increment to avoid iterator becoming invalid.
         const auto maybeErase = iter++;
         if (maybeErase->second.fromPeer == peer) {
             nErased += EraseOrphanTx(maybeErase->second.tx->GetId());
         }
     }
     if (nErased > 0) {
         LogPrint(BCLog::MEMPOOL, "Erased %d orphan tx from peer=%d\n", nErased,
                  peer);
     }
 }
 
 unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) {
     LOCK(g_cs_orphans);
 
     unsigned int nEvicted = 0;
     static int64_t nNextSweep;
     int64_t nNow = GetTime();
     if (nNextSweep <= nNow) {
         // Sweep out expired orphan pool entries:
         int nErased = 0;
         int64_t nMinExpTime =
             nNow + ORPHAN_TX_EXPIRE_TIME - ORPHAN_TX_EXPIRE_INTERVAL;
         auto iter = mapOrphanTransactions.begin();
         while (iter != mapOrphanTransactions.end()) {
             const auto maybeErase = iter++;
             if (maybeErase->second.nTimeExpire <= nNow) {
                 nErased += EraseOrphanTx(maybeErase->second.tx->GetId());
             } else {
                 nMinExpTime =
                     std::min(maybeErase->second.nTimeExpire, nMinExpTime);
             }
         }
         // Sweep again 5 minutes after the next entry that expires in order to
         // batch the linear scan.
         nNextSweep = nMinExpTime + ORPHAN_TX_EXPIRE_INTERVAL;
         if (nErased > 0) {
             LogPrint(BCLog::MEMPOOL, "Erased %d orphan tx due to expiration\n",
                      nErased);
         }
     }
     FastRandomContext rng;
     while (mapOrphanTransactions.size() > nMaxOrphans) {
         // Evict a random orphan:
         size_t randompos = rng.randrange(g_orphan_list.size());
         EraseOrphanTx(g_orphan_list[randompos]->first);
         ++nEvicted;
     }
     return nEvicted;
 }
 
 /**
  * Mark a misbehaving peer to be banned depending upon the value of `-banscore`.
  */
 void Misbehaving(NodeId pnode, int howmuch, const std::string &reason) {
     AssertLockHeld(cs_main);
     if (howmuch == 0) {
         return;
     }
 
     CNodeState *state = State(pnode);
     if (state == nullptr) {
         return;
     }
 
     state->nMisbehavior += howmuch;
     int banscore = gArgs.GetArg("-banscore", DEFAULT_BANSCORE_THRESHOLD);
     if (state->nMisbehavior >= banscore &&
         state->nMisbehavior - howmuch < banscore) {
         LogPrintf(
             "%s: %s peer=%d (%d -> %d) reason: %s BAN THRESHOLD EXCEEDED\n",
             __func__, state->name, pnode, state->nMisbehavior - howmuch,
             state->nMisbehavior, reason);
         state->m_should_discourage = true;
     } else {
         LogPrintf("%s: %s peer=%d (%d -> %d) reason: %s\n", __func__,
                   state->name, pnode, state->nMisbehavior - howmuch,
                   state->nMisbehavior, reason);
     }
 }
 
 // overloaded variant of above to operate on CNode*s
 static void Misbehaving(const CNode &node, int howmuch,
                         const std::string &reason)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     Misbehaving(node.GetId(), howmuch, reason);
 }
 
 /**
  * Returns true if the given validation state result may result in a peer
  * banning/disconnecting us. We use this to determine which unaccepted
  * transactions from a whitelisted peer that we can safely relay.
  */
 static bool TxRelayMayResultInDisconnect(const TxValidationState &state) {
     return state.GetResult() == TxValidationResult::TX_CONSENSUS;
 }
 
 /**
  * Potentially ban a node based on the contents of a BlockValidationState object
  *
  * @param[in] via_compact_block: this bool is passed in because net_processing
  * should punish peers differently depending on whether the data was provided in
  * a compact block message or not. If the compact block had a valid header, but
  * contained invalid txs, the peer should not be punished. See BIP 152.
  *
  * @return Returns true if the peer was punished (probably disconnected)
  */
 static bool MaybePunishNodeForBlock(NodeId nodeid,
                                     const BlockValidationState &state,
                                     bool via_compact_block,
                                     const std::string &message = "") {
     switch (state.GetResult()) {
         case BlockValidationResult::BLOCK_RESULT_UNSET:
             break;
         // The node is providing invalid data:
         case BlockValidationResult::BLOCK_CONSENSUS:
         case BlockValidationResult::BLOCK_MUTATED:
             if (!via_compact_block) {
                 LOCK(cs_main);
                 Misbehaving(nodeid, 100, message);
                 return true;
             }
             break;
         case BlockValidationResult::BLOCK_CACHED_INVALID: {
             LOCK(cs_main);
             CNodeState *node_state = State(nodeid);
             if (node_state == nullptr) {
                 break;
             }
 
             // Ban outbound (but not inbound) peers if on an invalid chain.
             // Exempt HB compact block peers and manual connections.
             if (!via_compact_block && !node_state->m_is_inbound &&
                 !node_state->m_is_manual_connection) {
                 Misbehaving(nodeid, 100, message);
                 return true;
             }
             break;
         }
         case BlockValidationResult::BLOCK_INVALID_HEADER:
         case BlockValidationResult::BLOCK_CHECKPOINT:
         case BlockValidationResult::BLOCK_INVALID_PREV: {
             LOCK(cs_main);
             Misbehaving(nodeid, 100, message);
         }
             return true;
         case BlockValidationResult::BLOCK_FINALIZATION: {
             // TODO: Use the state object to report this is probably not the
             // best idea. This is effectively unreachable, unless there is a bug
             // somewhere.
             LOCK(cs_main);
             Misbehaving(nodeid, 20, message);
         }
             return true;
         // Conflicting (but not necessarily invalid) data or different policy:
         case BlockValidationResult::BLOCK_MISSING_PREV: {
             // TODO: Handle this much more gracefully (10 DoS points is super
             // arbitrary)
             LOCK(cs_main);
             Misbehaving(nodeid, 10, message);
         }
             return true;
         case BlockValidationResult::BLOCK_RECENT_CONSENSUS_CHANGE:
         case BlockValidationResult::BLOCK_TIME_FUTURE:
             break;
     }
     if (message != "") {
         LogPrint(BCLog::NET, "peer=%d: %s\n", nodeid, message);
     }
     return false;
 }
 
 /**
  * Potentially ban a node based on the contents of a TxValidationState object
  *
  * @return Returns true if the peer was punished (probably disconnected)
  *
  * Changes here may need to be reflected in TxRelayMayResultInDisconnect().
  */
 static bool MaybePunishNodeForTx(NodeId nodeid, const TxValidationState &state,
                                  const std::string &message = "") {
     switch (state.GetResult()) {
         case TxValidationResult::TX_RESULT_UNSET:
             break;
         // The node is providing invalid data:
         case TxValidationResult::TX_CONSENSUS: {
             LOCK(cs_main);
             Misbehaving(nodeid, 100, message);
             return true;
         }
         // Conflicting (but not necessarily invalid) data or different policy:
         case TxValidationResult::TX_RECENT_CONSENSUS_CHANGE:
         case TxValidationResult::TX_NOT_STANDARD:
         case TxValidationResult::TX_MISSING_INPUTS:
         case TxValidationResult::TX_PREMATURE_SPEND:
         case TxValidationResult::TX_CONFLICT:
         case TxValidationResult::TX_MEMPOOL_POLICY:
             break;
     }
     if (message != "") {
         LogPrint(BCLog::NET, "peer=%d: %s\n", nodeid, message);
     }
     return false;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // blockchain -> download logic notification
 //
 
 // To prevent fingerprinting attacks, only send blocks/headers outside of the
 // active chain if they are no more than a month older (both in time, and in
 // best equivalent proof of work) than the best header chain we know about and
 // we fully-validated them at some point.
 static bool BlockRequestAllowed(const CBlockIndex *pindex,
                                 const Consensus::Params &consensusParams)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     if (::ChainActive().Contains(pindex)) {
         return true;
     }
     return pindex->IsValid(BlockValidity::SCRIPTS) &&
            (pindexBestHeader != nullptr) &&
            (pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() <
             STALE_RELAY_AGE_LIMIT) &&
            (GetBlockProofEquivalentTime(*pindexBestHeader, *pindex,
                                         *pindexBestHeader, consensusParams) <
             STALE_RELAY_AGE_LIMIT);
 }
 
 PeerLogicValidation::PeerLogicValidation(CConnman *connmanIn, BanMan *banman,
                                          CScheduler &scheduler,
                                          ChainstateManager &chainman)
     : connman(connmanIn), m_banman(banman), m_chainman(chainman),
       m_stale_tip_check_time(0) {
     // Initialize global variables that cannot be constructed at startup.
     recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
 
     const Consensus::Params &consensusParams = Params().GetConsensus();
     // Stale tip checking and peer eviction are on two different timers, but we
     // don't want them to get out of sync due to drift in the scheduler, so we
     // combine them in one function and schedule at the quicker (peer-eviction)
     // timer.
     static_assert(
         EXTRA_PEER_CHECK_INTERVAL < STALE_CHECK_INTERVAL,
         "peer eviction timer should be less than stale tip check timer");
     scheduler.scheduleEvery(
         [this, &consensusParams]() {
             this->CheckForStaleTipAndEvictPeers(consensusParams);
             return true;
         },
         std::chrono::seconds{EXTRA_PEER_CHECK_INTERVAL});
 }
 
 /**
  * Evict orphan txn pool entries (EraseOrphanTx) based on a newly connected
  * block. Also save the time of the last tip update.
  */
 void PeerLogicValidation::BlockConnected(
     const std::shared_ptr<const CBlock> &pblock, const CBlockIndex *pindex,
     const std::vector<CTransactionRef> &vtxConflicted) {
     LOCK(g_cs_orphans);
 
     std::vector<TxId> vOrphanErase;
 
     for (const CTransactionRef &ptx : pblock->vtx) {
         const CTransaction &tx = *ptx;
 
         // Which orphan pool entries must we evict?
         for (const auto &txin : tx.vin) {
             auto itByPrev = mapOrphanTransactionsByPrev.find(txin.prevout);
             if (itByPrev == mapOrphanTransactionsByPrev.end()) {
                 continue;
             }
 
             for (auto mi = itByPrev->second.begin();
                  mi != itByPrev->second.end(); ++mi) {
                 const CTransaction &orphanTx = *(*mi)->second.tx;
                 const TxId &orphanId = orphanTx.GetId();
                 vOrphanErase.push_back(orphanId);
             }
         }
     }
 
     // Erase orphan transactions included or precluded by this block
     if (vOrphanErase.size()) {
         int nErased = 0;
         for (const auto &orphanId : vOrphanErase) {
             nErased += EraseOrphanTx(orphanId);
         }
         LogPrint(BCLog::MEMPOOL,
                  "Erased %d orphan tx included or conflicted by block\n",
                  nErased);
     }
 
     g_last_tip_update = GetTime();
 }
 
 // All of the following cache a recent block, and are protected by
 // cs_most_recent_block
 static RecursiveMutex cs_most_recent_block;
 static std::shared_ptr<const CBlock>
     most_recent_block GUARDED_BY(cs_most_recent_block);
 static std::shared_ptr<const CBlockHeaderAndShortTxIDs>
     most_recent_compact_block GUARDED_BY(cs_most_recent_block);
 static uint256 most_recent_block_hash GUARDED_BY(cs_most_recent_block);
 
 /**
  * Maintain state about the best-seen block and fast-announce a compact block
  * to compatible peers.
  */
 void PeerLogicValidation::NewPoWValidBlock(
     const CBlockIndex *pindex, const std::shared_ptr<const CBlock> &pblock) {
     std::shared_ptr<const CBlockHeaderAndShortTxIDs> pcmpctblock =
         std::make_shared<const CBlockHeaderAndShortTxIDs>(*pblock);
     const CNetMsgMaker msgMaker(PROTOCOL_VERSION);
 
     LOCK(cs_main);
 
     static int nHighestFastAnnounce = 0;
     if (pindex->nHeight <= nHighestFastAnnounce) {
         return;
     }
     nHighestFastAnnounce = pindex->nHeight;
 
     uint256 hashBlock(pblock->GetHash());
 
     {
         LOCK(cs_most_recent_block);
         most_recent_block_hash = hashBlock;
         most_recent_block = pblock;
         most_recent_compact_block = pcmpctblock;
     }
 
     connman->ForEachNode([this, &pcmpctblock, pindex, &msgMaker,
                           &hashBlock](CNode *pnode) {
         AssertLockHeld(cs_main);
 
         // TODO: Avoid the repeated-serialization here
         if (pnode->nVersion < INVALID_CB_NO_BAN_VERSION || pnode->fDisconnect) {
             return;
         }
         ProcessBlockAvailability(pnode->GetId());
         CNodeState &state = *State(pnode->GetId());
         // If the peer has, or we announced to them the previous block already,
         // but we don't think they have this one, go ahead and announce it.
         if (state.fPreferHeaderAndIDs && !PeerHasHeader(&state, pindex) &&
             PeerHasHeader(&state, pindex->pprev)) {
             LogPrint(BCLog::NET, "%s sending header-and-ids %s to peer=%d\n",
                      "PeerLogicValidation::NewPoWValidBlock",
                      hashBlock.ToString(), pnode->GetId());
             connman->PushMessage(
                 pnode, msgMaker.Make(NetMsgType::CMPCTBLOCK, *pcmpctblock));
             state.pindexBestHeaderSent = pindex;
         }
     });
 }
 
 /**
  * Update our best height and announce any block hashes which weren't previously
  * in ::ChainActive() to our peers.
  */
 void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew,
                                           const CBlockIndex *pindexFork,
                                           bool fInitialDownload) {
     const int nNewHeight = pindexNew->nHeight;
     connman->SetBestHeight(nNewHeight);
 
     SetServiceFlagsIBDCache(!fInitialDownload);
     if (!fInitialDownload) {
         // Find the hashes of all blocks that weren't previously in the best
         // chain.
         std::vector<BlockHash> vHashes;
         const CBlockIndex *pindexToAnnounce = pindexNew;
         while (pindexToAnnounce != pindexFork) {
             vHashes.push_back(pindexToAnnounce->GetBlockHash());
             pindexToAnnounce = pindexToAnnounce->pprev;
             if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) {
                 // Limit announcements in case of a huge reorganization. Rely on
                 // the peer's synchronization mechanism in that case.
                 break;
             }
         }
         // Relay inventory, but don't relay old inventory during initial block
         // download.
         connman->ForEachNode([nNewHeight, &vHashes](CNode *pnode) {
             if (nNewHeight > (pnode->nStartingHeight != -1
                                   ? pnode->nStartingHeight - 2000
                                   : 0)) {
                 for (const BlockHash &hash : reverse_iterate(vHashes)) {
                     pnode->PushBlockHash(hash);
                 }
             }
         });
         connman->WakeMessageHandler();
     }
 }
 
 /**
  * Handle invalid block rejection and consequent peer banning, maintain which
  * peers announce compact blocks.
  */
 void PeerLogicValidation::BlockChecked(const CBlock &block,
                                        const BlockValidationState &state) {
     LOCK(cs_main);
 
     const BlockHash hash = block.GetHash();
     std::map<BlockHash, std::pair<NodeId, bool>>::iterator it =
         mapBlockSource.find(hash);
 
     // If the block failed validation, we know where it came from and we're
     // still connected to that peer, maybe punish.
     if (state.IsInvalid() && it != mapBlockSource.end() &&
         State(it->second.first)) {
         MaybePunishNodeForBlock(/*nodeid=*/it->second.first, state,
                                 /*via_compact_block=*/!it->second.second);
     }
     // Check that:
     // 1. The block is valid
     // 2. We're not in initial block download
     // 3. This is currently the best block we're aware of. We haven't updated
     //    the tip yet so we have no way to check this directly here. Instead we
     //    just check that there are currently no other blocks in flight.
     else if (state.IsValid() &&
              !::ChainstateActive().IsInitialBlockDownload() &&
              mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {
         if (it != mapBlockSource.end()) {
             MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first, *connman);
         }
     }
 
     if (it != mapBlockSource.end()) {
         mapBlockSource.erase(it);
     }
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // Messages
 //
 
 static bool AlreadyHave(const CInv &inv) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     switch (inv.type) {
         case MSG_TX: {
             assert(recentRejects);
             if (::ChainActive().Tip()->GetBlockHash() !=
                 hashRecentRejectsChainTip) {
                 // If the chain tip has changed previously rejected transactions
                 // might be now valid, e.g. due to a nLockTime'd tx becoming
                 // valid, or a double-spend. Reset the rejects filter and give
                 // those txs a second chance.
                 hashRecentRejectsChainTip =
                     ::ChainActive().Tip()->GetBlockHash();
                 recentRejects->reset();
             }
 
             {
                 LOCK(g_cs_orphans);
                 if (mapOrphanTransactions.count(TxId{inv.hash})) {
                     return true;
                 }
             }
             const CCoinsViewCache &coins_cache =
                 ::ChainstateActive().CoinsTip();
 
             // Use pcoinsTip->HaveCoinInCache as a quick approximation to
             // exclude requesting or processing some txs which have already been
             // included in a block. As this is best effort, we only check for
             // output 0 and 1. This works well enough in practice and we get
             // diminishing returns with 2 onward.
             const TxId txid(inv.hash);
             return recentRejects->contains(inv.hash) ||
                    g_mempool.exists(txid) ||
                    coins_cache.HaveCoinInCache(COutPoint(txid, 0)) ||
                    coins_cache.HaveCoinInCache(COutPoint(txid, 1));
         }
         case MSG_BLOCK:
             return LookupBlockIndex(BlockHash(inv.hash)) != nullptr;
     }
     // Don't know what it is, just say we already got one
     return true;
 }
 
 void RelayTransaction(const TxId &txid, const CConnman &connman) {
     CInv inv(MSG_TX, txid);
     connman.ForEachNode([&inv](CNode *pnode) { pnode->PushInventory(inv); });
 }
 
 static void RelayAddress(const CAddress &addr, bool fReachable,
                          const CConnman &connman) {
     // Limited relaying of addresses outside our network(s)
     unsigned int nRelayNodes = fReachable ? 2 : 1;
 
     // Relay to a limited number of other nodes.
     // Use deterministic randomness to send to the same nodes for 24 hours at a
     // time so the m_addr_knowns of the chosen nodes prevent repeats
     uint64_t hashAddr = addr.GetHash();
     const CSipHasher hasher =
         connman.GetDeterministicRandomizer(RANDOMIZER_ID_ADDRESS_RELAY)
             .Write(hashAddr << 32)
             .Write((GetTime() + hashAddr) / (24 * 60 * 60));
     FastRandomContext insecure_rand;
 
     std::array<std::pair<uint64_t, CNode *>, 2> best{
         {{0, nullptr}, {0, nullptr}}};
     assert(nRelayNodes <= best.size());
 
     auto sortfunc = [&best, &hasher, nRelayNodes](CNode *pnode) {
         if (pnode->IsAddrRelayPeer()) {
             uint64_t hashKey =
                 CSipHasher(hasher).Write(pnode->GetId()).Finalize();
             for (unsigned int i = 0; i < nRelayNodes; i++) {
                 if (hashKey > best[i].first) {
                     std::copy(best.begin() + i, best.begin() + nRelayNodes - 1,
                               best.begin() + i + 1);
                     best[i] = std::make_pair(hashKey, pnode);
                     break;
                 }
             }
         }
     };
 
     auto pushfunc = [&addr, &best, nRelayNodes, &insecure_rand] {
         for (unsigned int i = 0; i < nRelayNodes && best[i].first != 0; i++) {
             best[i].second->PushAddress(addr, insecure_rand);
         }
     };
 
     connman.ForEachNodeThen(std::move(sortfunc), std::move(pushfunc));
 }
 
 static void ProcessGetBlockData(const Config &config, CNode &pfrom,
                                 const CInv &inv, CConnman &connman,
                                 const std::atomic<bool> &interruptMsgProc) {
     const Consensus::Params &consensusParams =
         config.GetChainParams().GetConsensus();
 
     const BlockHash hash(inv.hash);
 
     bool send = false;
     std::shared_ptr<const CBlock> a_recent_block;
     std::shared_ptr<const CBlockHeaderAndShortTxIDs> a_recent_compact_block;
     {
         LOCK(cs_most_recent_block);
         a_recent_block = most_recent_block;
         a_recent_compact_block = most_recent_compact_block;
     }
 
     bool need_activate_chain = false;
     {
         LOCK(cs_main);
         const CBlockIndex *pindex = LookupBlockIndex(hash);
         if (pindex) {
             if (pindex->HaveTxsDownloaded() &&
                 !pindex->IsValid(BlockValidity::SCRIPTS) &&
                 pindex->IsValid(BlockValidity::TREE)) {
                 // If we have the block and all of its parents, but have not yet
                 // validated it, we might be in the middle of connecting it (ie
                 // in the unlock of cs_main before ActivateBestChain but after
                 // AcceptBlock). In this case, we need to run ActivateBestChain
                 // prior to checking the relay conditions below.
                 need_activate_chain = true;
             }
         }
     } // release cs_main before calling ActivateBestChain
     if (need_activate_chain) {
         BlockValidationState state;
         if (!ActivateBestChain(config, state, a_recent_block)) {
             LogPrint(BCLog::NET, "failed to activate chain (%s)\n",
                      state.ToString());
         }
     }
 
     LOCK(cs_main);
     const CBlockIndex *pindex = LookupBlockIndex(hash);
     if (pindex) {
         send = BlockRequestAllowed(pindex, consensusParams);
         if (!send) {
             LogPrint(BCLog::NET,
                      "%s: ignoring request from peer=%i for old "
                      "block that isn't in the main chain\n",
                      __func__, pfrom.GetId());
         }
     }
     const CNetMsgMaker msgMaker(pfrom.GetSendVersion());
     // Disconnect node in case we have reached the outbound limit for serving
     // historical blocks.
     // Never disconnect whitelisted nodes.
     if (send && connman.OutboundTargetReached(true) &&
         (((pindexBestHeader != nullptr) &&
           (pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() >
            HISTORICAL_BLOCK_AGE)) ||
          inv.type == MSG_FILTERED_BLOCK) &&
         !pfrom.HasPermission(PF_NOBAN)) {
         LogPrint(BCLog::NET,
                  "historical block serving limit reached, disconnect peer=%d\n",
                  pfrom.GetId());
 
         // disconnect node
         pfrom.fDisconnect = true;
         send = false;
     }
     // Avoid leaking prune-height by never sending blocks below the
     // NODE_NETWORK_LIMITED threshold.
     // Add two blocks buffer extension for possible races
     if (send && !pfrom.HasPermission(PF_NOBAN) &&
         ((((pfrom.GetLocalServices() & NODE_NETWORK_LIMITED) ==
            NODE_NETWORK_LIMITED) &&
           ((pfrom.GetLocalServices() & NODE_NETWORK) != NODE_NETWORK) &&
           (::ChainActive().Tip()->nHeight - pindex->nHeight >
            (int)NODE_NETWORK_LIMITED_MIN_BLOCKS + 2)))) {
         LogPrint(BCLog::NET,
                  "Ignore block request below NODE_NETWORK_LIMITED "
                  "threshold from peer=%d\n",
                  pfrom.GetId());
 
         // disconnect node and prevent it from stalling (would otherwise wait
         // for the missing block)
         pfrom.fDisconnect = true;
         send = false;
     }
     // Pruned nodes may have deleted the block, so check whether it's available
     // before trying to send.
     if (send && pindex->nStatus.hasData()) {
         std::shared_ptr<const CBlock> pblock;
         if (a_recent_block &&
             a_recent_block->GetHash() == pindex->GetBlockHash()) {
             pblock = a_recent_block;
         } else {
             // Send block from disk
             std::shared_ptr<CBlock> pblockRead = std::make_shared<CBlock>();
             if (!ReadBlockFromDisk(*pblockRead, pindex, consensusParams)) {
                 assert(!"cannot load block from disk");
             }
             pblock = pblockRead;
         }
         if (inv.type == MSG_BLOCK) {
             connman.PushMessage(&pfrom,
                                 msgMaker.Make(NetMsgType::BLOCK, *pblock));
         } else if (inv.type == MSG_FILTERED_BLOCK) {
             bool sendMerkleBlock = false;
             CMerkleBlock merkleBlock;
             if (pfrom.m_tx_relay != nullptr) {
                 LOCK(pfrom.m_tx_relay->cs_filter);
                 if (pfrom.m_tx_relay->pfilter) {
                     sendMerkleBlock = true;
                     merkleBlock =
                         CMerkleBlock(*pblock, *pfrom.m_tx_relay->pfilter);
                 }
             }
             if (sendMerkleBlock) {
                 connman.PushMessage(
                     &pfrom,
                     msgMaker.Make(NetMsgType::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 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.
                 typedef std::pair<size_t, uint256> PairType;
                 for (PairType &pair : merkleBlock.vMatchedTxn) {
                     connman.PushMessage(
                         &pfrom, msgMaker.Make(NetMsgType::TX,
                                               *pblock->vtx[pair.first]));
                 }
             }
             // else
             // no response
         } else if (inv.type == MSG_CMPCT_BLOCK) {
             // If a peer is asking for old blocks, we're almost guaranteed they
             // won't have a useful mempool to match against a compact block, and
             // we don't feel like constructing the object for them, so instead
             // we respond with the full, non-compact block.
             int nSendFlags = 0;
             if (CanDirectFetch(consensusParams) &&
                 pindex->nHeight >=
                     ::ChainActive().Height() - MAX_CMPCTBLOCK_DEPTH) {
                 CBlockHeaderAndShortTxIDs cmpctblock(*pblock);
                 connman.PushMessage(
                     &pfrom, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK,
                                           cmpctblock));
             } else {
                 connman.PushMessage(
                     &pfrom,
                     msgMaker.Make(nSendFlags, NetMsgType::BLOCK, *pblock));
             }
         }
 
         // Trigger the peer node to send a getblocks request for the next batch
         // of inventory.
         if (hash == pfrom.hashContinue) {
             // Bypass PushInventory, this must send even if redundant, and we
             // want it right after the last block so they don't wait for other
             // stuff first.
             std::vector<CInv> vInv;
             vInv.push_back(
                 CInv(MSG_BLOCK, ::ChainActive().Tip()->GetBlockHash()));
             connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::INV, vInv));
             pfrom.hashContinue = BlockHash();
         }
     }
 }
 
 static void ProcessGetData(const Config &config, CNode &pfrom,
                            CConnman &connman,
                            const std::atomic<bool> &interruptMsgProc)
     LOCKS_EXCLUDED(cs_main) {
     AssertLockNotHeld(cs_main);
 
     std::deque<CInv>::iterator it = pfrom.vRecvGetData.begin();
     std::vector<CInv> vNotFound;
     const CNetMsgMaker msgMaker(pfrom.GetSendVersion());
 
     // Note that if we receive a getdata for a MSG_TX from a block-relay-only
     // outbound peer, we will stop processing further getdata messages from this
     // peer (likely resulting in our peer eventually disconnecting us).
     if (pfrom.m_tx_relay != nullptr) {
         // mempool entries added before this time have likely expired from
         // mapRelay
         const std::chrono::seconds longlived_mempool_time =
             GetTime<std::chrono::seconds>() - RELAY_TX_CACHE_TIME;
         const std::chrono::seconds mempool_req =
             pfrom.m_tx_relay->m_last_mempool_req.load();
 
         LOCK(cs_main);
 
         while (it != pfrom.vRecvGetData.end() && it->type == MSG_TX) {
             if (interruptMsgProc) {
                 return;
             }
             // Don't bother if send buffer is too full to respond anyway.
             if (pfrom.fPauseSend) {
                 break;
             }
 
             const CInv &inv = *it;
             it++;
 
             // Send stream from relay memory
             bool push = false;
             auto mi = mapRelay.find(inv.hash);
             int nSendFlags = 0;
             if (mi != mapRelay.end()) {
                 connman.PushMessage(
                     &pfrom,
                     msgMaker.Make(nSendFlags, NetMsgType::TX, *mi->second));
                 push = true;
             } else {
                 auto txinfo = g_mempool.info(TxId(inv.hash));
                 // To protect privacy, do not answer getdata using the mempool
                 // when that TX couldn't have been INVed in reply to a MEMPOOL
                 // request, or when it's too recent to have expired from
                 // mapRelay.
                 if (txinfo.tx &&
                     ((mempool_req.count() && txinfo.m_time <= mempool_req) ||
                      (txinfo.m_time <= longlived_mempool_time))) {
                     connman.PushMessage(
                         &pfrom,
                         msgMaker.Make(nSendFlags, NetMsgType::TX, *txinfo.tx));
                     push = true;
                 }
             }
             if (!push) {
                 vNotFound.push_back(inv);
             }
         }
     } // release cs_main
 
     if (it != pfrom.vRecvGetData.end() && !pfrom.fPauseSend) {
         const CInv &inv = *it;
         if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK ||
             inv.type == MSG_CMPCT_BLOCK) {
             it++;
             ProcessGetBlockData(config, pfrom, inv, connman, interruptMsgProc);
         }
     }
 
     // Unknown types in the GetData stay in vRecvGetData and block any future
     // message from this peer, see vRecvGetData check in ProcessMessages().
     // Depending on future p2p changes, we might either drop unknown getdata on
     // the floor or disconnect the peer.
 
     pfrom.vRecvGetData.erase(pfrom.vRecvGetData.begin(), it);
 
     if (!vNotFound.empty()) {
         // Let the peer know that we didn't find what it asked for, so it
         // doesn't have to wait around forever. SPV clients care about this
         // message: it's needed when they are recursively walking the
         // dependencies of relevant unconfirmed transactions. SPV clients want
         // to do that because they want to know about (and store and rebroadcast
         // and risk analyze) the dependencies of transactions relevant to them,
         // without having to download the entire memory pool. Also, other nodes
         // can use these messages to automatically request a transaction from
         // some other peer that annnounced it, and stop waiting for us to
         // respond. In normal operation, we often send NOTFOUND messages for
         // parents of transactions that we relay; if a peer is missing a parent,
         // they may assume we have them and request the parents from us.
         connman.PushMessage(&pfrom,
                             msgMaker.Make(NetMsgType::NOTFOUND, vNotFound));
     }
 }
 
 inline static void SendBlockTransactions(const CBlock &block,
                                          const BlockTransactionsRequest &req,
                                          CNode &pfrom, CConnman &connman) {
     BlockTransactions resp(req);
     for (size_t i = 0; i < req.indices.size(); i++) {
         if (req.indices[i] >= block.vtx.size()) {
             LOCK(cs_main);
             Misbehaving(pfrom, 100, "out-of-bound-tx-index");
             LogPrintf(
                 "Peer %d sent us a getblocktxn with out-of-bounds tx indices\n",
                 pfrom.GetId());
             return;
         }
         resp.txn[i] = block.vtx[req.indices[i]];
     }
     LOCK(cs_main);
     const CNetMsgMaker msgMaker(pfrom.GetSendVersion());
     int nSendFlags = 0;
     connman.PushMessage(&pfrom,
                         msgMaker.Make(nSendFlags, NetMsgType::BLOCKTXN, resp));
 }
 
 static bool ProcessHeadersMessage(const Config &config, CNode &pfrom,
                                   CConnman &connman,
                                   ChainstateManager &chainman,
                                   const std::vector<CBlockHeader> &headers,
                                   bool via_compact_block) {
     const CChainParams &chainparams = config.GetChainParams();
     const CNetMsgMaker msgMaker(pfrom.GetSendVersion());
     size_t nCount = headers.size();
 
     if (nCount == 0) {
         // Nothing interesting. Stop asking this peers for more headers.
         return true;
     }
 
     bool received_new_header = false;
     const CBlockIndex *pindexLast = nullptr;
     {
         LOCK(cs_main);
         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 (!LookupBlockIndex(headers[0].hashPrevBlock) &&
             nCount < MAX_BLOCKS_TO_ANNOUNCE) {
             nodestate->nUnconnectingHeaders++;
             connman.PushMessage(
                 &pfrom,
                 msgMaker.Make(NetMsgType::GETHEADERS,
                               ::ChainActive().GetLocator(pindexBestHeader),
                               uint256()));
             LogPrint(
                 BCLog::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.GetId(), 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) {
                 // The peer is sending us many headers we can't connect.
                 Misbehaving(pfrom, 20, "too-many-unconnected-headers");
             }
             return true;
         }
 
         BlockHash hashLastBlock;
         for (const CBlockHeader &header : headers) {
             if (!hashLastBlock.IsNull() &&
                 header.hashPrevBlock != hashLastBlock) {
                 Misbehaving(pfrom, 20, "disconnected-header");
                 return error("non-continuous headers sequence");
             }
             hashLastBlock = header.GetHash();
         }
 
         // If we don't have the last header, then they'll have given us
         // something new (if these headers are valid).
         if (!LookupBlockIndex(hashLastBlock)) {
             received_new_header = true;
         }
     }
 
     BlockValidationState state;
     if (!chainman.ProcessNewBlockHeaders(config, headers, state, &pindexLast)) {
         if (state.IsInvalid()) {
             MaybePunishNodeForBlock(pfrom.GetId(), state, via_compact_block,
                                     "invalid header received");
             return false;
         }
     }
 
     {
         LOCK(cs_main);
         CNodeState *nodestate = State(pfrom.GetId());
         if (nodestate->nUnconnectingHeaders > 0) {
             LogPrint(BCLog::NET,
                      "peer=%d: resetting nUnconnectingHeaders (%d -> 0)\n",
                      pfrom.GetId(), nodestate->nUnconnectingHeaders);
         }
         nodestate->nUnconnectingHeaders = 0;
 
         assert(pindexLast);
         UpdateBlockAvailability(pfrom.GetId(), pindexLast->GetBlockHash());
 
         // From here, pindexBestKnownBlock should be guaranteed to be non-null,
         // because it is set in UpdateBlockAvailability. Some nullptr checks are
         // still present, however, as belt-and-suspenders.
 
         if (received_new_header &&
             pindexLast->nChainWork > ::ChainActive().Tip()->nChainWork) {
             nodestate->m_last_block_announcement = GetTime();
         }
 
         if (nCount == MAX_HEADERS_RESULTS) {
             // Headers message had its maximum size; the peer may have more
             // headers.
             // TODO: optimize: if pindexLast is an ancestor of
             // ::ChainActive().Tip or pindexBestHeader, continue from there
             // instead.
             LogPrint(
                 BCLog::NET,
                 "more getheaders (%d) to end to peer=%d (startheight:%d)\n",
                 pindexLast->nHeight, pfrom.GetId(), pfrom.nStartingHeight);
             connman.PushMessage(
                 &pfrom, msgMaker.Make(NetMsgType::GETHEADERS,
                                       ::ChainActive().GetLocator(pindexLast),
                                       uint256()));
         }
 
         bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus());
         // 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(BlockValidity::TREE) &&
             ::ChainActive().Tip()->nChainWork <= pindexLast->nChainWork) {
             std::vector<const CBlockIndex *> vToFetch;
             const CBlockIndex *pindexWalk = pindexLast;
             // Calculate all the blocks we'd need to switch to pindexLast, up to
             // a limit.
             while (pindexWalk && !::ChainActive().Contains(pindexWalk) &&
                    vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                 if (!pindexWalk->nStatus.hasData() &&
                     !mapBlocksInFlight.count(pindexWalk->GetBlockHash())) {
                     // We don't have this block, and it's not yet in flight.
                     vToFetch.push_back(pindexWalk);
                 }
                 pindexWalk = pindexWalk->pprev;
             }
             // If pindexWalk still isn't on our main chain, we're looking at a
             // very large reorg at a time we think we're close to caught up to
             // the main chain -- this shouldn't really happen. Bail out on the
             // direct fetch and rely on parallel download instead.
             if (!::ChainActive().Contains(pindexWalk)) {
                 LogPrint(
                     BCLog::NET, "Large reorg, won't direct fetch to %s (%d)\n",
                     pindexLast->GetBlockHash().ToString(), pindexLast->nHeight);
             } else {
                 std::vector<CInv> vGetData;
                 // Download as much as possible, from earliest to latest.
                 for (const CBlockIndex *pindex : reverse_iterate(vToFetch)) {
                     if (nodestate->nBlocksInFlight >=
                         MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                         // Can't download any more from this peer
                         break;
                     }
                     vGetData.push_back(CInv(MSG_BLOCK, pindex->GetBlockHash()));
                     MarkBlockAsInFlight(config, pfrom.GetId(),
                                         pindex->GetBlockHash(),
                                         chainparams.GetConsensus(), pindex);
                     LogPrint(BCLog::NET, "Requesting block %s from  peer=%d\n",
                              pindex->GetBlockHash().ToString(), pfrom.GetId());
                 }
                 if (vGetData.size() > 1) {
                     LogPrint(BCLog::NET,
                              "Downloading blocks toward %s (%d) via headers "
                              "direct fetch\n",
                              pindexLast->GetBlockHash().ToString(),
                              pindexLast->nHeight);
                 }
                 if (vGetData.size() > 0) {
                     if (nodestate->fSupportsDesiredCmpctVersion &&
                         vGetData.size() == 1 && mapBlocksInFlight.size() == 1 &&
                         pindexLast->pprev->IsValid(BlockValidity::CHAIN)) {
                         // In any case, we want to download using a compact
                         // block, not a regular one.
                         vGetData[0] = CInv(MSG_CMPCT_BLOCK, vGetData[0].hash);
                     }
                     connman.PushMessage(
                         &pfrom, msgMaker.Make(NetMsgType::GETDATA, vGetData));
                 }
             }
         }
         // If we're in IBD, we want outbound peers that will serve us a useful
         // chain. Disconnect peers that are on chains with insufficient work.
         if (::ChainstateActive().IsInitialBlockDownload() &&
             nCount != MAX_HEADERS_RESULTS) {
             // When nCount < MAX_HEADERS_RESULTS, we know we have no more
             // headers to fetch from this peer.
             if (nodestate->pindexBestKnownBlock &&
                 nodestate->pindexBestKnownBlock->nChainWork <
                     nMinimumChainWork) {
                 // This peer has too little work on their headers chain to help
                 // us sync -- disconnect if using an outbound slot (unless
                 // whitelisted or addnode).
                 // Note: We compare their tip to nMinimumChainWork (rather than
                 // ::ChainActive().Tip()) because we won't start block download
                 // until we have a headers chain that has at least
                 // nMinimumChainWork, even if a peer has a chain past our tip,
                 // as an anti-DoS measure.
                 if (IsOutboundDisconnectionCandidate(pfrom)) {
                     LogPrintf("Disconnecting outbound peer %d -- headers "
                               "chain has insufficient work\n",
                               pfrom.GetId());
                     pfrom.fDisconnect = true;
                 }
             }
         }
 
         if (!pfrom.fDisconnect && IsOutboundDisconnectionCandidate(pfrom) &&
             nodestate->pindexBestKnownBlock != nullptr &&
             pfrom.m_tx_relay != nullptr) {
             // If this is an outbound full-relay peer, check to see if we should
             // protect it from the bad/lagging chain logic. Note that
             // block-relay-only peers are already implicitly protected, so we
             // only consider setting m_protect for the full-relay peers.
             if (g_outbound_peers_with_protect_from_disconnect <
                     MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT &&
                 nodestate->pindexBestKnownBlock->nChainWork >=
                     ::ChainActive().Tip()->nChainWork &&
                 !nodestate->m_chain_sync.m_protect) {
                 LogPrint(BCLog::NET,
                          "Protecting outbound peer=%d from eviction\n",
                          pfrom.GetId());
                 nodestate->m_chain_sync.m_protect = true;
                 ++g_outbound_peers_with_protect_from_disconnect;
             }
         }
     }
 
     return true;
 }
 
 void static ProcessOrphanTx(const Config &config, CConnman &connman,
                             std::set<TxId> &orphan_work_set)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main, g_cs_orphans) {
     AssertLockHeld(cs_main);
     AssertLockHeld(g_cs_orphans);
     std::unordered_map<NodeId, uint32_t> rejectCountPerNode;
     bool done = false;
     while (!done && !orphan_work_set.empty()) {
         const TxId orphanTxId = *orphan_work_set.begin();
         orphan_work_set.erase(orphan_work_set.begin());
 
         auto orphan_it = mapOrphanTransactions.find(orphanTxId);
         if (orphan_it == mapOrphanTransactions.end()) {
             continue;
         }
 
         const CTransactionRef porphanTx = orphan_it->second.tx;
         const CTransaction &orphanTx = *porphanTx;
         NodeId fromPeer = orphan_it->second.fromPeer;
         // Use a new TxValidationState because orphans come from different peers
         // (and we call MaybePunishNodeForTx based on the source peer from the
         // orphan map, not based on the peer that relayed the previous
         // transaction).
         TxValidationState orphan_state;
 
         auto it = rejectCountPerNode.find(fromPeer);
         if (it != rejectCountPerNode.end() &&
             it->second > MAX_NON_STANDARD_ORPHAN_PER_NODE) {
             continue;
         }
 
         if (AcceptToMemoryPool(config, g_mempool, orphan_state, porphanTx,
                                false /* bypass_limits */,
                                Amount::zero() /* nAbsurdFee */)) {
             LogPrint(BCLog::MEMPOOL, "   accepted orphan tx %s\n",
                      orphanTxId.ToString());
             RelayTransaction(orphanTxId, connman);
             for (size_t i = 0; i < orphanTx.vout.size(); i++) {
                 auto it_by_prev =
                     mapOrphanTransactionsByPrev.find(COutPoint(orphanTxId, i));
                 if (it_by_prev != mapOrphanTransactionsByPrev.end()) {
                     for (const auto &elem : it_by_prev->second) {
                         orphan_work_set.insert(elem->first);
                     }
                 }
             }
             EraseOrphanTx(orphanTxId);
             done = true;
         } else if (orphan_state.GetResult() !=
                    TxValidationResult::TX_MISSING_INPUTS) {
             if (orphan_state.IsInvalid()) {
                 // Punish peer that gave us an invalid orphan tx
                 MaybePunishNodeForTx(fromPeer, orphan_state);
                 LogPrint(BCLog::MEMPOOL, "   invalid orphan tx %s\n",
                          orphanTxId.ToString());
             }
             // Has inputs but not accepted to mempool
             // Probably non-standard or insufficient fee
             LogPrint(BCLog::MEMPOOL, "   removed orphan tx %s\n",
                      orphanTxId.ToString());
 
             assert(recentRejects);
             recentRejects->insert(orphanTxId);
 
             EraseOrphanTx(orphanTxId);
             done = true;
         }
         g_mempool.check(&::ChainstateActive().CoinsTip());
     }
 }
 
 /**
  * Validation logic for compact filters request handling.
  *
  * May disconnect from the peer in the case of a bad request.
  *
  * @param[in]   pfrom           The peer that we received the request from
  * @param[in]   chain_params    Chain parameters
  * @param[in]   filter_type      The filter type the request is for. Must be
  * basic filters.
  * @param[in]   start_height    The start height for the request
  * @param[in]   stop_hash       The stop_hash for the request
  * @param[in]   max_height_diff  The maximum number of items permitted to
  * request, as specified in BIP 157
  * @param[out]  stop_index      The CBlockIndex for the stop_hash block, if the
  * request can be serviced.
  * @param[out]  filter_index     The filter index, if the request can be
  * serviced.
  * @return                      True if the request can be serviced.
  */
 static bool PrepareBlockFilterRequest(
     CNode &pfrom, const CChainParams &chain_params, BlockFilterType filter_type,
     uint32_t start_height, const BlockHash &stop_hash, uint32_t max_height_diff,
     const CBlockIndex *&stop_index, BlockFilterIndex *&filter_index) {
     const bool supported_filter_type =
         (filter_type == BlockFilterType::BASIC &&
          gArgs.GetBoolArg("-peerblockfilters", DEFAULT_PEERBLOCKFILTERS));
     if (!supported_filter_type) {
         LogPrint(BCLog::NET,
                  "peer %d requested unsupported block filter type: %d\n",
                  pfrom.GetId(), static_cast<uint8_t>(filter_type));
         pfrom.fDisconnect = true;
         return false;
     }
 
     {
         LOCK(cs_main);
         stop_index = LookupBlockIndex(stop_hash);
 
         // Check that the stop block exists and the peer would be allowed to
         // fetch it.
         if (!stop_index ||
             !BlockRequestAllowed(stop_index, chain_params.GetConsensus())) {
             LogPrint(BCLog::NET, "peer %d requested invalid block hash: %s\n",
                      pfrom.GetId(), stop_hash.ToString());
             pfrom.fDisconnect = true;
             return false;
         }
     }
 
     uint32_t stop_height = stop_index->nHeight;
     if (start_height > stop_height) {
         LogPrint(
             BCLog::NET,
             "peer %d sent invalid getcfilters/getcfheaders with " /* Continued
                                                                    */
             "start height %d and stop height %d\n",
             pfrom.GetId(), start_height, stop_height);
         pfrom.fDisconnect = true;
         return false;
     }
     if (stop_height - start_height >= max_height_diff) {
         LogPrint(BCLog::NET,
                  "peer %d requested too many cfilters/cfheaders: %d / %d\n",
                  pfrom.GetId(), stop_height - start_height + 1,
                  max_height_diff);
         pfrom.fDisconnect = true;
         return false;
     }
 
     filter_index = GetBlockFilterIndex(filter_type);
     if (!filter_index) {
         LogPrint(BCLog::NET, "Filter index for supported type %s not found\n",
                  BlockFilterTypeName(filter_type));
         return false;
     }
 
     return true;
 }
 
 /**
  * Handle a cfilters request.
  *
  * May disconnect from the peer in the case of a bad request.
  *
  * @param[in]   pfrom           The peer that we received the request from
  * @param[in]   vRecv           The raw message received
  * @param[in]   chain_params    Chain parameters
  * @param[in]   connman         Pointer to the connection manager
  */
 static void ProcessGetCFilters(CNode &pfrom, CDataStream &vRecv,
                                const CChainParams &chain_params,
                                CConnman &connman) {
     uint8_t filter_type_ser;
     uint32_t start_height;
     BlockHash stop_hash;
 
     vRecv >> filter_type_ser >> start_height >> stop_hash;
 
     const BlockFilterType filter_type =
         static_cast<BlockFilterType>(filter_type_ser);
 
     const CBlockIndex *stop_index;
     BlockFilterIndex *filter_index;
     if (!PrepareBlockFilterRequest(
             pfrom, chain_params, filter_type, start_height, stop_hash,
             MAX_GETCFILTERS_SIZE, stop_index, filter_index)) {
         return;
     }
 
     std::vector<BlockFilter> filters;
 
     if (!filter_index->LookupFilterRange(start_height, stop_index, filters)) {
         LogPrint(BCLog::NET,
                  "Failed to find block filter in index: filter_type=%s, "
                  "start_height=%d, stop_hash=%s\n",
                  BlockFilterTypeName(filter_type), start_height,
                  stop_hash.ToString());
         return;
     }
 
     for (const auto &filter : filters) {
         CSerializedNetMsg msg = CNetMsgMaker(pfrom.GetSendVersion())
                                     .Make(NetMsgType::CFILTER, filter);
         connman.PushMessage(&pfrom, std::move(msg));
     }
 }
 
 /**
  * Handle a cfheaders request.
  *
  * May disconnect from the peer in the case of a bad request.
  *
  * @param[in]   pfrom           The peer that we received the request from
  * @param[in]   vRecv           The raw message received
  * @param[in]   chain_params    Chain parameters
  * @param[in]   connman         Pointer to the connection manager
  */
 static void ProcessGetCFHeaders(CNode &pfrom, CDataStream &vRecv,
                                 const CChainParams &chain_params,
                                 CConnman &connman) {
     uint8_t filter_type_ser;
     uint32_t start_height;
     BlockHash stop_hash;
 
     vRecv >> filter_type_ser >> start_height >> stop_hash;
 
     const BlockFilterType filter_type =
         static_cast<BlockFilterType>(filter_type_ser);
 
     const CBlockIndex *stop_index;
     BlockFilterIndex *filter_index;
     if (!PrepareBlockFilterRequest(
             pfrom, chain_params, filter_type, start_height, stop_hash,
             MAX_GETCFHEADERS_SIZE, stop_index, filter_index)) {
         return;
     }
 
     uint256 prev_header;
     if (start_height > 0) {
         const CBlockIndex *const prev_block =
             stop_index->GetAncestor(static_cast<int>(start_height - 1));
         if (!filter_index->LookupFilterHeader(prev_block, prev_header)) {
             LogPrint(BCLog::NET,
                      "Failed to find block filter header in index: "
                      "filter_type=%s, block_hash=%s\n",
                      BlockFilterTypeName(filter_type),
                      prev_block->GetBlockHash().ToString());
             return;
         }
     }
 
     std::vector<uint256> filter_hashes;
     if (!filter_index->LookupFilterHashRange(start_height, stop_index,
                                              filter_hashes)) {
         LogPrint(BCLog::NET,
                  "Failed to find block filter hashes in index: filter_type=%s, "
                  "start_height=%d, stop_hash=%s\n",
                  BlockFilterTypeName(filter_type), start_height,
                  stop_hash.ToString());
         return;
     }
 
     CSerializedNetMsg msg =
         CNetMsgMaker(pfrom.GetSendVersion())
             .Make(NetMsgType::CFHEADERS, filter_type_ser,
                   stop_index->GetBlockHash(), prev_header, filter_hashes);
     connman.PushMessage(&pfrom, std::move(msg));
 }
 
 /**
  * Handle a getcfcheckpt request.
  *
  * May disconnect from the peer in the case of a bad request.
  *
  * @param[in]   pfrom           The peer that we received the request from
  * @param[in]   vRecv           The raw message received
  * @param[in]   chain_params    Chain parameters
  * @param[in]   connman         Pointer to the connection manager
  */
 static void ProcessGetCFCheckPt(CNode &pfrom, CDataStream &vRecv,
                                 const CChainParams &chain_params,
                                 CConnman &connman) {
     uint8_t filter_type_ser;
     BlockHash stop_hash;
 
     vRecv >> filter_type_ser >> stop_hash;
 
     const BlockFilterType filter_type =
         static_cast<BlockFilterType>(filter_type_ser);
 
     const CBlockIndex *stop_index;
     BlockFilterIndex *filter_index;
     if (!PrepareBlockFilterRequest(
             pfrom, chain_params, filter_type, /*start_height=*/0, stop_hash,
             /*max_height_diff=*/std::numeric_limits<uint32_t>::max(),
             stop_index, filter_index)) {
         return;
     }
 
     std::vector<uint256> headers(stop_index->nHeight / CFCHECKPT_INTERVAL);
 
     // Populate headers.
     const CBlockIndex *block_index = stop_index;
     for (int i = headers.size() - 1; i >= 0; i--) {
         int height = (i + 1) * CFCHECKPT_INTERVAL;
         block_index = block_index->GetAncestor(height);
 
         if (!filter_index->LookupFilterHeader(block_index, headers[i])) {
             LogPrint(BCLog::NET,
                      "Failed to find block filter header in index: "
                      "filter_type=%s, block_hash=%s\n",
                      BlockFilterTypeName(filter_type),
                      block_index->GetBlockHash().ToString());
             return;
         }
     }
 
     CSerializedNetMsg msg = CNetMsgMaker(pfrom.GetSendVersion())
                                 .Make(NetMsgType::CFCHECKPT, filter_type_ser,
                                       stop_index->GetBlockHash(), headers);
     connman.PushMessage(&pfrom, std::move(msg));
 }
 
 bool ProcessMessage(const Config &config, CNode &pfrom,
                     const std::string &msg_type, CDataStream &vRecv,
                     int64_t nTimeReceived, ChainstateManager &chainman,
                     CConnman &connman, BanMan *banman,
                     const std::atomic<bool> &interruptMsgProc) {
     const CChainParams &chainparams = config.GetChainParams();
     LogPrint(BCLog::NET, "received: %s (%u bytes) peer=%d\n",
              SanitizeString(msg_type), vRecv.size(), pfrom.GetId());
     if (gArgs.IsArgSet("-dropmessagestest") &&
         GetRand(gArgs.GetArg("-dropmessagestest", 0)) == 0) {
         LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n");
         return true;
     }
 
     if (!(pfrom.GetLocalServices() & NODE_BLOOM) &&
         (msg_type == NetMsgType::FILTERLOAD ||
          msg_type == NetMsgType::FILTERADD)) {
         if (pfrom.nVersion >= NO_BLOOM_VERSION) {
             LOCK(cs_main);
             Misbehaving(pfrom, 100, "no-bloom-version");
             return false;
         } else {
             pfrom.fDisconnect = true;
             return false;
         }
     }
 
     if (msg_type == NetMsgType::VERSION) {
         // Each connection can only send one version message
         if (pfrom.nVersion != 0) {
             LOCK(cs_main);
             Misbehaving(pfrom, 1, "multiple-version");
             return false;
         }
 
         int64_t nTime;
         CAddress addrMe;
         CAddress addrFrom;
         uint64_t nNonce = 1;
         uint64_t nServiceInt;
         ServiceFlags nServices;
         int nVersion;
         int nSendVersion;
         std::string cleanSubVer;
         int nStartingHeight = -1;
         bool fRelay = true;
 
         vRecv >> nVersion >> nServiceInt >> nTime >> addrMe;
         nSendVersion = std::min(nVersion, PROTOCOL_VERSION);
         nServices = ServiceFlags(nServiceInt);
         if (!pfrom.fInbound) {
             connman.SetServices(pfrom.addr, nServices);
         }
         if (!pfrom.fInbound && !pfrom.fFeeler && !pfrom.m_manual_connection &&
             !HasAllDesirableServiceFlags(nServices)) {
             LogPrint(BCLog::NET,
                      "peer=%d does not offer the expected services "
                      "(%08x offered, %08x expected); disconnecting\n",
                      pfrom.GetId(), nServices,
                      GetDesirableServiceFlags(nServices));
             pfrom.fDisconnect = true;
             return false;
         }
 
         if (nVersion < MIN_PEER_PROTO_VERSION) {
             // disconnect from peers older than this proto version
             LogPrint(BCLog::NET,
                      "peer=%d using obsolete version %i; disconnecting\n",
                      pfrom.GetId(), nVersion);
             pfrom.fDisconnect = true;
             return false;
         }
 
         if (!vRecv.empty()) {
             vRecv >> addrFrom >> nNonce;
         }
         if (!vRecv.empty()) {
             std::string strSubVer;
             vRecv >> LIMITED_STRING(strSubVer, MAX_SUBVERSION_LENGTH);
             cleanSubVer = SanitizeString(strSubVer);
         }
         if (!vRecv.empty()) {
             vRecv >> nStartingHeight;
         }
         if (!vRecv.empty()) {
             vRecv >> fRelay;
         }
         // Disconnect if we connected to ourself
         if (pfrom.fInbound && !connman.CheckIncomingNonce(nNonce)) {
             LogPrintf("connected to self at %s, disconnecting\n",
                       pfrom.addr.ToString());
             pfrom.fDisconnect = true;
             return true;
         }
 
         if (pfrom.fInbound && addrMe.IsRoutable()) {
             SeenLocal(addrMe);
         }
 
         // Be shy and don't send version until we hear
         if (pfrom.fInbound) {
             PushNodeVersion(config, pfrom, connman, GetAdjustedTime());
         }
 
         connman.PushMessage(
             &pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERACK));
 
         pfrom.nServices = nServices;
         pfrom.SetAddrLocal(addrMe);
         {
             LOCK(pfrom.cs_SubVer);
             pfrom.cleanSubVer = cleanSubVer;
         }
         pfrom.nStartingHeight = nStartingHeight;
 
         // set nodes not relaying blocks and tx and not serving (parts) of the
         // historical blockchain as "clients"
         pfrom.fClient = (!(nServices & NODE_NETWORK) &&
                          !(nServices & NODE_NETWORK_LIMITED));
 
         // set nodes not capable of serving the complete blockchain history as
         // "limited nodes"
         pfrom.m_limited_node =
             (!(nServices & NODE_NETWORK) && (nServices & NODE_NETWORK_LIMITED));
 
         if (pfrom.m_tx_relay != nullptr) {
             LOCK(pfrom.m_tx_relay->cs_filter);
             // set to true after we get the first filter* message
             pfrom.m_tx_relay->fRelayTxes = fRelay;
         }
 
         // Change version
         pfrom.SetSendVersion(nSendVersion);
         pfrom.nVersion = nVersion;
 
         // Potentially mark this peer as a preferred download peer.
         {
             LOCK(cs_main);
             UpdatePreferredDownload(pfrom, State(pfrom.GetId()));
         }
 
         if (!pfrom.fInbound && pfrom.IsAddrRelayPeer()) {
             // Advertise our address
             if (fListen && !::ChainstateActive().IsInitialBlockDownload()) {
                 CAddress addr =
                     GetLocalAddress(&pfrom.addr, pfrom.GetLocalServices());
                 FastRandomContext insecure_rand;
                 if (addr.IsRoutable()) {
                     LogPrint(BCLog::NET,
                              "ProcessMessages: advertising address %s\n",
                              addr.ToString());
                     pfrom.PushAddress(addr, insecure_rand);
                 } else if (IsPeerAddrLocalGood(&pfrom)) {
                     addr.SetIP(addrMe);
                     LogPrint(BCLog::NET,
                              "ProcessMessages: advertising address %s\n",
                              addr.ToString());
                     pfrom.PushAddress(addr, insecure_rand);
                 }
             }
 
             // Get recent addresses
             connman.PushMessage(
                 &pfrom, CNetMsgMaker(nSendVersion).Make(NetMsgType::GETADDR));
             pfrom.fGetAddr = true;
             connman.MarkAddressGood(pfrom.addr);
         }
 
         std::string remoteAddr;
         if (fLogIPs) {
             remoteAddr = ", peeraddr=" + pfrom.addr.ToString();
         }
 
         LogPrint(BCLog::NET,
                  "receive version message: [%s] %s: version %d, blocks=%d, "
                  "us=%s, peer=%d%s\n",
                  pfrom.addr.ToString(), cleanSubVer, pfrom.nVersion,
                  pfrom.nStartingHeight, addrMe.ToString(), pfrom.GetId(),
                  remoteAddr);
 
         // Ignore time offsets that are improbable (before the Genesis block)
         // and may underflow the nTimeOffset calculation.
         int64_t currentTime = GetTime();
         if (nTime >= int64_t(chainparams.GenesisBlock().nTime)) {
             int64_t nTimeOffset = nTime - currentTime;
             pfrom.nTimeOffset = nTimeOffset;
             AddTimeData(pfrom.addr, nTimeOffset);
         } else {
             LOCK(cs_main);
             Misbehaving(pfrom, 20,
                         "Ignoring invalid timestamp in version message");
         }
 
         // Feeler connections exist only to verify if address is online.
         if (pfrom.fFeeler) {
             assert(pfrom.fInbound == false);
             pfrom.fDisconnect = true;
         }
         return true;
     }
 
     if (pfrom.nVersion == 0) {
         // Must have a version message before anything else
         LOCK(cs_main);
         Misbehaving(pfrom, 10, "missing-version");
         return false;
     }
 
     // At this point, the outgoing message serialization version can't change.
     const CNetMsgMaker msgMaker(pfrom.GetSendVersion());
 
     if (msg_type == NetMsgType::VERACK) {
         pfrom.SetRecvVersion(std::min(pfrom.nVersion.load(), PROTOCOL_VERSION));
 
         if (!pfrom.fInbound) {
             // Mark this node as currently connected, so we update its timestamp
             // later.
             LOCK(cs_main);
             State(pfrom.GetId())->fCurrentlyConnected = true;
             LogPrintf(
                 "New outbound peer connected: version: %d, blocks=%d, "
                 "peer=%d%s (%s)\n",
                 pfrom.nVersion.load(), pfrom.nStartingHeight, pfrom.GetId(),
                 (fLogIPs ? strprintf(", peeraddr=%s", pfrom.addr.ToString())
                          : ""),
                 pfrom.m_tx_relay == nullptr ? "block-relay" : "full-relay");
         }
 
         if (pfrom.nVersion >= SENDHEADERS_VERSION) {
             // Tell our peer we prefer to receive headers rather than inv's
             // We send this to non-NODE NETWORK peers as well, because even
             // non-NODE NETWORK peers can announce blocks (such as pruning
             // nodes)
             connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDHEADERS));
         }
         if (pfrom.nVersion >= SHORT_IDS_BLOCKS_VERSION) {
             // Tell our peer we are willing to provide version 1 or 2
             // cmpctblocks. However, we do not request new block announcements
             // using cmpctblock messages. We send this to non-NODE NETWORK peers
             // as well, because they may wish to request compact blocks from us.
             bool fAnnounceUsingCMPCTBLOCK = false;
             uint64_t nCMPCTBLOCKVersion = 1;
             connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDCMPCT,
                                                       fAnnounceUsingCMPCTBLOCK,
                                                       nCMPCTBLOCKVersion));
         }
         pfrom.fSuccessfullyConnected = true;
         return true;
     }
 
     if (!pfrom.fSuccessfullyConnected) {
         // Must have a verack message before anything else
         LOCK(cs_main);
         Misbehaving(pfrom, 10, "missing-verack");
         return false;
     }
 
     if (msg_type == NetMsgType::ADDR) {
         std::vector<CAddress> vAddr;
         vRecv >> vAddr;
 
         if (!pfrom.IsAddrRelayPeer()) {
             return true;
         }
         if (vAddr.size() > 1000) {
             LOCK(cs_main);
             Misbehaving(pfrom, 20, "oversized-addr");
             return error("message addr size() = %u", vAddr.size());
         }
 
         // Store the new addresses
         std::vector<CAddress> vAddrOk;
         int64_t nNow = GetAdjustedTime();
         int64_t nSince = nNow - 10 * 60;
         for (CAddress &addr : vAddr) {
             if (interruptMsgProc) {
                 return true;
             }
 
             // We only bother storing full nodes, though this may include things
             // which we would not make an outbound connection to, in part
             // because we may make feeler connections to them.
             if (!MayHaveUsefulAddressDB(addr.nServices) &&
                 !HasAllDesirableServiceFlags(addr.nServices)) {
                 continue;
             }
 
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60) {
                 addr.nTime = nNow - 5 * 24 * 60 * 60;
             }
             pfrom.AddAddressKnown(addr);
             // Do not process banned/discouraged addresses beyond remembering we
             // received them
             if (banman->IsDiscouraged(addr)) {
                 continue;
             }
             if (banman->IsBanned(addr)) {
                 continue;
             }
             bool fReachable = IsReachable(addr);
             if (addr.nTime > nSince && !pfrom.fGetAddr && vAddr.size() <= 10 &&
                 addr.IsRoutable()) {
                 // Relay to a limited number of other nodes
                 RelayAddress(addr, fReachable, connman);
             }
             // Do not store addresses outside our network
             if (fReachable) {
                 vAddrOk.push_back(addr);
             }
         }
 
         connman.AddNewAddresses(vAddrOk, pfrom.addr, 2 * 60 * 60);
         if (vAddr.size() < 1000) {
             pfrom.fGetAddr = false;
         }
         if (pfrom.fOneShot) {
             pfrom.fDisconnect = true;
         }
         return true;
     }
 
     if (msg_type == NetMsgType::SENDHEADERS) {
         LOCK(cs_main);
         State(pfrom.GetId())->fPreferHeaders = true;
         return true;
     }
 
     if (msg_type == NetMsgType::SENDCMPCT) {
         bool fAnnounceUsingCMPCTBLOCK = false;
         uint64_t nCMPCTBLOCKVersion = 0;
         vRecv >> fAnnounceUsingCMPCTBLOCK >> nCMPCTBLOCKVersion;
         if (nCMPCTBLOCKVersion == 1) {
             LOCK(cs_main);
             // fProvidesHeaderAndIDs is used to "lock in" version of compact
             // blocks we send.
             if (!State(pfrom.GetId())->fProvidesHeaderAndIDs) {
                 State(pfrom.GetId())->fProvidesHeaderAndIDs = true;
             }
 
             State(pfrom.GetId())->fPreferHeaderAndIDs =
                 fAnnounceUsingCMPCTBLOCK;
             if (!State(pfrom.GetId())->fSupportsDesiredCmpctVersion) {
                 State(pfrom.GetId())->fSupportsDesiredCmpctVersion = true;
             }
         }
         return true;
     }
 
     if (msg_type == NetMsgType::INV) {
         std::vector<CInv> vInv;
         vRecv >> vInv;
         if (vInv.size() > MAX_INV_SZ) {
             LOCK(cs_main);
             Misbehaving(pfrom, 20, "oversized-inv");
             return error("message inv size() = %u", vInv.size());
         }
 
         // We won't accept tx inv's if we're in blocks-only mode, or this is a
         // block-relay-only peer
         bool fBlocksOnly = !g_relay_txes || (pfrom.m_tx_relay == nullptr);
 
         // Allow whitelisted peers to send data other than blocks in blocks only
         // mode if whitelistrelay is true
         if (pfrom.HasPermission(PF_RELAY)) {
             fBlocksOnly = false;
         }
 
         LOCK(cs_main);
 
         const auto current_time = GetTime<std::chrono::microseconds>();
 
         for (CInv &inv : vInv) {
             if (interruptMsgProc) {
                 return true;
             }
 
             bool fAlreadyHave = AlreadyHave(inv);
             LogPrint(BCLog::NET, "got inv: %s  %s peer=%d\n", inv.ToString(),
                      fAlreadyHave ? "have" : "new", pfrom.GetId());
 
             if (inv.type == MSG_BLOCK) {
                 const BlockHash hash(inv.hash);
                 UpdateBlockAvailability(pfrom.GetId(), hash);
                 if (!fAlreadyHave && !fImporting && !fReindex &&
                     !mapBlocksInFlight.count(hash)) {
                     // We used to request the full block here, but since
                     // headers-announcements are now the primary method of
                     // announcement on the network, and since, in the case that
                     // a node fell back to inv we probably have a reorg which we
                     // should get the headers for first, we now only provide a
                     // getheaders response here. When we receive the headers, we
                     // will then ask for the blocks we need.
                     connman.PushMessage(
                         &pfrom, msgMaker.Make(NetMsgType::GETHEADERS,
                                               ::ChainActive().GetLocator(
                                                   pindexBestHeader),
                                               hash));
                     LogPrint(BCLog::NET, "getheaders (%d) %s to peer=%d\n",
                              pindexBestHeader->nHeight, hash.ToString(),
                              pfrom.GetId());
                 }
             } else {
                 const TxId txid(inv.hash);
                 pfrom.AddKnownTx(txid);
                 if (fBlocksOnly) {
                     LogPrint(BCLog::NET,
                              "transaction (%s) inv sent in violation of "
                              "protocol, disconnecting peer=%d\n",
                              txid.ToString(), pfrom.GetId());
                     pfrom.fDisconnect = true;
                     return true;
                 } else if (!fAlreadyHave && !fImporting && !fReindex &&
                            !::ChainstateActive().IsInitialBlockDownload()) {
                     RequestTx(State(pfrom.GetId()), txid, current_time);
                 }
             }
         }
         return true;
     }
 
     if (msg_type == NetMsgType::GETDATA) {
         std::vector<CInv> vInv;
         vRecv >> vInv;
         if (vInv.size() > MAX_INV_SZ) {
             LOCK(cs_main);
             Misbehaving(pfrom, 20, "too-many-inv");
             return error("message getdata size() = %u", vInv.size());
         }
 
         LogPrint(BCLog::NET, "received getdata (%u invsz) peer=%d\n",
                  vInv.size(), pfrom.GetId());
 
         if (vInv.size() > 0) {
             LogPrint(BCLog::NET, "received getdata for: %s peer=%d\n",
                      vInv[0].ToString(), pfrom.GetId());
         }
 
         pfrom.vRecvGetData.insert(pfrom.vRecvGetData.end(), vInv.begin(),
                                   vInv.end());
         ProcessGetData(config, pfrom, connman, interruptMsgProc);
         return true;
     }
 
     if (msg_type == NetMsgType::GETBLOCKS) {
         CBlockLocator locator;
         uint256 hashStop;
         vRecv >> locator >> hashStop;
 
         if (locator.vHave.size() > MAX_LOCATOR_SZ) {
             LogPrint(BCLog::NET,
                      "getblocks locator size %lld > %d, disconnect peer=%d\n",
                      locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId());
             pfrom.fDisconnect = true;
             return true;
         }
 
         // We might have announced the currently-being-connected tip using a
         // compact block, which resulted in the peer sending a getblocks
         // request, which we would otherwise respond to without the new block.
         // To avoid this situation we simply verify that we are on our best
         // known chain now. This is super overkill, but we handle it better
         // for getheaders requests, and there are no known nodes which support
         // compact blocks but still use getblocks to request blocks.
         {
             std::shared_ptr<const CBlock> a_recent_block;
             {
                 LOCK(cs_most_recent_block);
                 a_recent_block = most_recent_block;
             }
             BlockValidationState state;
             if (!ActivateBestChain(config, state, a_recent_block)) {
                 LogPrint(BCLog::NET, "failed to activate chain (%s)\n",
                          state.ToString());
             }
         }
 
         LOCK(cs_main);
 
         // Find the last block the caller has in the main chain
         const CBlockIndex *pindex =
             FindForkInGlobalIndex(::ChainActive(), locator);
 
         // Send the rest of the chain
         if (pindex) {
             pindex = ::ChainActive().Next(pindex);
         }
         int nLimit = 500;
         LogPrint(BCLog::NET, "getblocks %d to %s limit %d from peer=%d\n",
                  (pindex ? pindex->nHeight : -1),
                  hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit,
                  pfrom.GetId());
         for (; pindex; pindex = ::ChainActive().Next(pindex)) {
             if (pindex->GetBlockHash() == hashStop) {
                 LogPrint(BCLog::NET, "  getblocks stopping at %d %s\n",
                          pindex->nHeight, pindex->GetBlockHash().ToString());
                 break;
             }
             // If pruning, don't inv blocks unless we have on disk and are
             // likely to still have for some reasonable time window (1 hour)
             // that block relay might require.
             const int nPrunedBlocksLikelyToHave =
                 MIN_BLOCKS_TO_KEEP -
                 3600 / chainparams.GetConsensus().nPowTargetSpacing;
             if (fPruneMode &&
                 (!pindex->nStatus.hasData() ||
                  pindex->nHeight <= ::ChainActive().Tip()->nHeight -
                                         nPrunedBlocksLikelyToHave)) {
                 LogPrint(
                     BCLog::NET,
                     " getblocks stopping, pruned or too old block at %d %s\n",
                     pindex->nHeight, pindex->GetBlockHash().ToString());
                 break;
             }
             pfrom.PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
             if (--nLimit <= 0) {
                 // When this block is requested, we'll send an inv that'll
                 // trigger the peer to getblocks the next batch of inventory.
                 LogPrint(BCLog::NET, "  getblocks stopping at limit %d %s\n",
                          pindex->nHeight, pindex->GetBlockHash().ToString());
                 pfrom.hashContinue = pindex->GetBlockHash();
                 break;
             }
         }
         return true;
     }
 
     if (msg_type == NetMsgType::GETBLOCKTXN) {
         BlockTransactionsRequest req;
         vRecv >> req;
 
         std::shared_ptr<const CBlock> recent_block;
         {
             LOCK(cs_most_recent_block);
             if (most_recent_block_hash == req.blockhash) {
                 recent_block = most_recent_block;
             }
             // Unlock cs_most_recent_block to avoid cs_main lock inversion
         }
         if (recent_block) {
             SendBlockTransactions(*recent_block, req, pfrom, connman);
             return true;
         }
 
         LOCK(cs_main);
 
         const CBlockIndex *pindex = LookupBlockIndex(req.blockhash);
         if (!pindex || !pindex->nStatus.hasData()) {
             LogPrint(
                 BCLog::NET,
                 "Peer %d sent us a getblocktxn for a block we don't have\n",
                 pfrom.GetId());
             return true;
         }
 
         if (pindex->nHeight < ::ChainActive().Height() - MAX_BLOCKTXN_DEPTH) {
             // If an older block is requested (should never happen in practice,
             // but can happen in tests) send a block response instead of a
             // blocktxn response. Sending a full block response instead of a
             // small blocktxn response is preferable in the case where a peer
             // might maliciously send lots of getblocktxn requests to trigger
             // expensive disk reads, because it will require the peer to
             // actually receive all the data read from disk over the network.
             LogPrint(BCLog::NET,
                      "Peer %d sent us a getblocktxn for a block > %i deep\n",
                      pfrom.GetId(), MAX_BLOCKTXN_DEPTH);
             CInv inv;
             inv.type = MSG_BLOCK;
             inv.hash = req.blockhash;
             pfrom.vRecvGetData.push_back(inv);
             // The message processing loop will go around again (without
             // pausing) and we'll respond then (without cs_main)
             return true;
         }
 
         CBlock block;
         bool ret = ReadBlockFromDisk(block, pindex, chainparams.GetConsensus());
         assert(ret);
 
         SendBlockTransactions(block, req, pfrom, connman);
         return true;
     }
 
     if (msg_type == NetMsgType::GETHEADERS) {
         CBlockLocator locator;
         BlockHash hashStop;
         vRecv >> locator >> hashStop;
 
         if (locator.vHave.size() > MAX_LOCATOR_SZ) {
             LogPrint(BCLog::NET,
                      "getheaders locator size %lld > %d, disconnect peer=%d\n",
                      locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId());
             pfrom.fDisconnect = true;
             return true;
         }
 
         LOCK(cs_main);
         if (::ChainstateActive().IsInitialBlockDownload() &&
             !pfrom.HasPermission(PF_NOBAN)) {
             LogPrint(BCLog::NET,
                      "Ignoring getheaders from peer=%d because node is in "
                      "initial block download\n",
                      pfrom.GetId());
             return true;
         }
 
         CNodeState *nodestate = State(pfrom.GetId());
         const CBlockIndex *pindex = nullptr;
         if (locator.IsNull()) {
             // If locator is null, return the hashStop block
             pindex = LookupBlockIndex(hashStop);
             if (!pindex) {
                 return true;
             }
 
             if (!BlockRequestAllowed(pindex, chainparams.GetConsensus())) {
                 LogPrint(BCLog::NET,
                          "%s: ignoring request from peer=%i for old block "
                          "header that isn't in the main chain\n",
                          __func__, pfrom.GetId());
                 return true;
             }
         } else {
             // Find the last block the caller has in the main chain
             pindex = FindForkInGlobalIndex(::ChainActive(), locator);
             if (pindex) {
                 pindex = ::ChainActive().Next(pindex);
             }
         }
 
         // we must use CBlocks, as CBlockHeaders won't include the 0x00 nTx
         // count at the end
         std::vector<CBlock> vHeaders;
         int nLimit = MAX_HEADERS_RESULTS;
         LogPrint(BCLog::NET, "getheaders %d to %s from peer=%d\n",
                  (pindex ? pindex->nHeight : -1),
                  hashStop.IsNull() ? "end" : hashStop.ToString(),
                  pfrom.GetId());
         for (; pindex; pindex = ::ChainActive().Next(pindex)) {
             vHeaders.push_back(pindex->GetBlockHeader());
             if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop) {
                 break;
             }
         }
         // pindex can be nullptr either if we sent ::ChainActive().Tip() OR
         // if our peer has ::ChainActive().Tip() (and thus we are sending an
         // empty headers message). In both cases it's safe to update
         // pindexBestHeaderSent to be our tip.
         //
         // It is important that we simply reset the BestHeaderSent value here,
         // and not max(BestHeaderSent, newHeaderSent). We might have announced
         // the currently-being-connected tip using a compact block, which
         // resulted in the peer sending a headers request, which we respond to
         // without the new block. By resetting the BestHeaderSent, we ensure we
         // will re-announce the new block via headers (or compact blocks again)
         // in the SendMessages logic.
         nodestate->pindexBestHeaderSent =
             pindex ? pindex : ::ChainActive().Tip();
         connman.PushMessage(&pfrom,
                             msgMaker.Make(NetMsgType::HEADERS, vHeaders));
         return true;
     }
 
     if (msg_type == NetMsgType::TX) {
         // Stop processing the transaction early if
         // We are in blocks only mode and peer is either not whitelisted or
         // whitelistrelay is off or if this peer is supposed to be a
         // block-relay-only peer
         if ((!g_relay_txes && !pfrom.HasPermission(PF_RELAY)) ||
             (pfrom.m_tx_relay == nullptr)) {
             LogPrint(BCLog::NET,
                      "transaction sent in violation of protocol peer=%d\n",
                      pfrom.GetId());
             pfrom.fDisconnect = true;
             return true;
         }
 
         CTransactionRef ptx;
         vRecv >> ptx;
         const CTransaction &tx = *ptx;
         const TxId &txid = tx.GetId();
         pfrom.AddKnownTx(txid);
 
         LOCK2(cs_main, g_cs_orphans);
 
         TxValidationState state;
 
         CNodeState *nodestate = State(pfrom.GetId());
         nodestate->m_tx_download.m_tx_announced.erase(txid);
         nodestate->m_tx_download.m_tx_in_flight.erase(txid);
         EraseTxRequest(txid);
 
         if (!AlreadyHave(CInv(MSG_TX, txid)) &&
             AcceptToMemoryPool(config, g_mempool, state, ptx,
                                false /* bypass_limits */,
                                Amount::zero() /* nAbsurdFee */)) {
             g_mempool.check(&::ChainstateActive().CoinsTip());
             RelayTransaction(tx.GetId(), connman);
             for (size_t i = 0; i < tx.vout.size(); i++) {
                 auto it_by_prev =
                     mapOrphanTransactionsByPrev.find(COutPoint(txid, i));
                 if (it_by_prev != mapOrphanTransactionsByPrev.end()) {
                     for (const auto &elem : it_by_prev->second) {
                         pfrom.orphan_work_set.insert(elem->first);
                     }
                 }
             }
 
             pfrom.nLastTXTime = GetTime();
 
             LogPrint(BCLog::MEMPOOL,
                      "AcceptToMemoryPool: peer=%d: accepted %s "
                      "(poolsz %u txn, %u kB)\n",
                      pfrom.GetId(), tx.GetId().ToString(), g_mempool.size(),
                      g_mempool.DynamicMemoryUsage() / 1000);
 
             // Recursively process any orphan transactions that depended on this
             // one
             ProcessOrphanTx(config, connman, pfrom.orphan_work_set);
         } else if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) {
             // It may be the case that the orphans parents have all been
             // rejected.
             bool fRejectedParents = false;
             for (const CTxIn &txin : tx.vin) {
                 if (recentRejects->contains(txin.prevout.GetTxId())) {
                     fRejectedParents = true;
                     break;
                 }
             }
             if (!fRejectedParents) {
                 const auto current_time = GetTime<std::chrono::microseconds>();
 
                 for (const CTxIn &txin : tx.vin) {
                     // FIXME: MSG_TX should use a TxHash, not a TxId.
                     const TxId _txid = txin.prevout.GetTxId();
                     pfrom.AddKnownTx(_txid);
                     if (!AlreadyHave(CInv(MSG_TX, _txid))) {
                         RequestTx(State(pfrom.GetId()), _txid, current_time);
                     }
                 }
                 AddOrphanTx(ptx, pfrom.GetId());
 
                 // DoS prevention: do not allow mapOrphanTransactions to grow
                 // unbounded (see CVE-2012-3789)
                 unsigned int nMaxOrphanTx = (unsigned int)std::max(
                     int64_t(0), gArgs.GetArg("-maxorphantx",
                                              DEFAULT_MAX_ORPHAN_TRANSACTIONS));
                 unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
                 if (nEvicted > 0) {
                     LogPrint(BCLog::MEMPOOL,
                              "mapOrphan overflow, removed %u tx\n", nEvicted);
                 }
             } else {
                 LogPrint(BCLog::MEMPOOL,
                          "not keeping orphan with rejected parents %s\n",
                          tx.GetId().ToString());
                 // We will continue to reject this tx since it has rejected
                 // parents so avoid re-requesting it from other peers.
                 recentRejects->insert(tx.GetId());
             }
         } else {
             assert(recentRejects);
             recentRejects->insert(tx.GetId());
 
             if (RecursiveDynamicUsage(*ptx) < 100000) {
                 AddToCompactExtraTransactions(ptx);
             }
 
             if (pfrom.HasPermission(PF_FORCERELAY)) {
                 // Always relay transactions received from whitelisted peers,
                 // even if they were already in the mempool or rejected from it
                 // due to policy, allowing the node to function as a gateway for
                 // nodes hidden behind it.
                 //
                 // Never relay transactions that might result in being
                 // disconnected (or banned).
                 if (state.IsInvalid() && TxRelayMayResultInDisconnect(state)) {
                     LogPrintf("Not relaying invalid transaction %s from "
                               "whitelisted peer=%d (%s)\n",
                               tx.GetId().ToString(), pfrom.GetId(),
                               state.ToString());
                 } else {
                     LogPrintf("Force relaying tx %s from whitelisted peer=%d\n",
                               tx.GetId().ToString(), pfrom.GetId());
                     RelayTransaction(tx.GetId(), connman);
                 }
             }
         }
 
         // If a tx has been detected by recentRejects, we will have reached
         // this point and the tx will have been ignored. Because we haven't run
         // the tx through AcceptToMemoryPool, we won't have computed a DoS
         // score for it or determined exactly why we consider it invalid.
         //
         // This means we won't penalize any peer subsequently relaying a DoSy
         // tx (even if we penalized the first peer who gave it to us) because
         // we have to account for recentRejects showing false positives. In
         // other words, we shouldn't penalize a peer if we aren't *sure* they
         // submitted a DoSy tx.
         //
         // Note that recentRejects doesn't just record DoSy or invalid
         // transactions, but any tx not accepted by the mempool, which may be
         // due to node policy (vs. consensus). So we can't blanket penalize a
         // peer simply for relaying a tx that our recentRejects has caught,
         // regardless of false positives.
 
         if (state.IsInvalid()) {
             LogPrint(BCLog::MEMPOOLREJ,
                      "%s from peer=%d was not accepted: %s\n",
                      tx.GetHash().ToString(), pfrom.GetId(), state.ToString());
             MaybePunishNodeForTx(pfrom.GetId(), state);
         }
         return true;
     }
 
     if (msg_type == NetMsgType::CMPCTBLOCK) {
         // Ignore cmpctblock received while importing
         if (fImporting || fReindex) {
             LogPrint(BCLog::NET,
                      "Unexpected cmpctblock message received from peer %d\n",
                      pfrom.GetId());
             return true;
         }
 
         CBlockHeaderAndShortTxIDs cmpctblock;
         vRecv >> cmpctblock;
 
         bool received_new_header = false;
 
         {
             LOCK(cs_main);
 
             if (!LookupBlockIndex(cmpctblock.header.hashPrevBlock)) {
                 // Doesn't connect (or is genesis), instead of DoSing in
                 // AcceptBlockHeader, request deeper headers
                 if (!::ChainstateActive().IsInitialBlockDownload()) {
                     connman.PushMessage(
                         &pfrom, msgMaker.Make(NetMsgType::GETHEADERS,
                                               ::ChainActive().GetLocator(
                                                   pindexBestHeader),
                                               uint256()));
                 }
                 return true;
             }
 
             if (!LookupBlockIndex(cmpctblock.header.GetHash())) {
                 received_new_header = true;
             }
         }
 
         const CBlockIndex *pindex = nullptr;
         BlockValidationState state;
         if (!chainman.ProcessNewBlockHeaders(config, {cmpctblock.header}, state,
                                              &pindex)) {
             if (state.IsInvalid()) {
                 MaybePunishNodeForBlock(pfrom.GetId(), state,
                                         /*via_compact_block*/ true,
                                         "invalid header via cmpctblock");
                 return true;
             }
         }
 
         // When we succeed in decoding a block's txids from a cmpctblock
         // message we typically jump to the BLOCKTXN handling code, with a
         // dummy (empty) BLOCKTXN message, to re-use the logic there in
         // completing processing of the putative block (without cs_main).
         bool fProcessBLOCKTXN = false;
         CDataStream blockTxnMsg(SER_NETWORK, PROTOCOL_VERSION);
 
         // If we end up treating this as a plain headers message, call that as
         // well
         // without cs_main.
         bool fRevertToHeaderProcessing = false;
 
         // Keep a CBlock for "optimistic" compactblock reconstructions (see
         // below)
         std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
         bool fBlockReconstructed = false;
 
         {
             LOCK2(cs_main, g_cs_orphans);
             // If AcceptBlockHeader returned true, it set pindex
             assert(pindex);
             UpdateBlockAvailability(pfrom.GetId(), pindex->GetBlockHash());
 
             CNodeState *nodestate = State(pfrom.GetId());
 
             // If this was a new header with more work than our tip, update the
             // peer's last block announcement time
             if (received_new_header &&
                 pindex->nChainWork > ::ChainActive().Tip()->nChainWork) {
                 nodestate->m_last_block_announcement = GetTime();
             }
 
             std::map<BlockHash,
                      std::pair<NodeId, std::list<QueuedBlock>::iterator>>::
                 iterator blockInFlightIt =
                     mapBlocksInFlight.find(pindex->GetBlockHash());
             bool fAlreadyInFlight = blockInFlightIt != mapBlocksInFlight.end();
 
             if (pindex->nStatus.hasData()) {
                 // Nothing to do here
                 return true;
             }
 
             if (pindex->nChainWork <=
                     ::ChainActive()
                         .Tip()
                         ->nChainWork || // We know something better
                 pindex->nTx != 0) {
                 // We had this block at some point, but pruned it
                 if (fAlreadyInFlight) {
                     // We requested this block for some reason, but our mempool
                     // will probably be useless so we just grab the block via
                     // normal getdata.
                     std::vector<CInv> vInv(1);
                     vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                     connman.PushMessage(
                         &pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                 }
                 return true;
             }
 
             // If we're not close to tip yet, give up and let parallel block
             // fetch work its magic.
             if (!fAlreadyInFlight &&
                 !CanDirectFetch(chainparams.GetConsensus())) {
                 return true;
             }
 
             // We want to be a bit conservative just to be extra careful about
             // DoS possibilities in compact block processing...
             if (pindex->nHeight <= ::ChainActive().Height() + 2) {
                 if ((!fAlreadyInFlight && nodestate->nBlocksInFlight <
                                               MAX_BLOCKS_IN_TRANSIT_PER_PEER) ||
                     (fAlreadyInFlight &&
                      blockInFlightIt->second.first == pfrom.GetId())) {
                     std::list<QueuedBlock>::iterator *queuedBlockIt = nullptr;
                     if (!MarkBlockAsInFlight(config, pfrom.GetId(),
                                              pindex->GetBlockHash(),
                                              chainparams.GetConsensus(), pindex,
                                              &queuedBlockIt)) {
                         if (!(*queuedBlockIt)->partialBlock) {
                             (*queuedBlockIt)
                                 ->partialBlock.reset(
                                     new PartiallyDownloadedBlock(config,
                                                                  &g_mempool));
                         } else {
                             // The block was already in flight using compact
                             // blocks from the same peer.
                             LogPrint(BCLog::NET, "Peer sent us compact block "
                                                  "we were already syncing!\n");
                             return true;
                         }
                     }
 
                     PartiallyDownloadedBlock &partialBlock =
                         *(*queuedBlockIt)->partialBlock;
                     ReadStatus status =
                         partialBlock.InitData(cmpctblock, vExtraTxnForCompact);
                     if (status == READ_STATUS_INVALID) {
                         // Reset in-flight state in case of whitelist
                         MarkBlockAsReceived(pindex->GetBlockHash());
                         Misbehaving(pfrom, 100, "invalid-cmpctblk");
                         LogPrintf("Peer %d sent us invalid compact block\n",
                                   pfrom.GetId());
                         return true;
                     } else if (status == READ_STATUS_FAILED) {
                         // Duplicate txindices, the block is now in-flight, so
                         // just request it.
                         std::vector<CInv> vInv(1);
                         vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                         connman.PushMessage(
                             &pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                         return true;
                     }
 
                     BlockTransactionsRequest req;
                     for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) {
                         if (!partialBlock.IsTxAvailable(i)) {
                             req.indices.push_back(i);
                         }
                     }
                     if (req.indices.empty()) {
                         // Dirty hack to jump to BLOCKTXN code (TODO: move
                         // message handling into their own functions)
                         BlockTransactions txn;
                         txn.blockhash = cmpctblock.header.GetHash();
                         blockTxnMsg << txn;
                         fProcessBLOCKTXN = true;
                     } else {
                         req.blockhash = pindex->GetBlockHash();
                         connman.PushMessage(
                             &pfrom,
                             msgMaker.Make(NetMsgType::GETBLOCKTXN, req));
                     }
                 } else {
                     // This block is either already in flight from a different
                     // peer, or this peer has too many blocks outstanding to
                     // download from. Optimistically try to reconstruct anyway
                     // since we might be able to without any round trips.
                     PartiallyDownloadedBlock tempBlock(config, &g_mempool);
                     ReadStatus status =
                         tempBlock.InitData(cmpctblock, vExtraTxnForCompact);
                     if (status != READ_STATUS_OK) {
                         // TODO: don't ignore failures
                         return true;
                     }
                     std::vector<CTransactionRef> dummy;
                     status = tempBlock.FillBlock(*pblock, dummy);
                     if (status == READ_STATUS_OK) {
                         fBlockReconstructed = true;
                     }
                 }
             } else {
                 if (fAlreadyInFlight) {
                     // We requested this block, but its far into the future, so
                     // our mempool will probably be useless - request the block
                     // normally.
                     std::vector<CInv> vInv(1);
                     vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                     connman.PushMessage(
                         &pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                     return true;
                 } else {
                     // If this was an announce-cmpctblock, we want the same
                     // treatment as a header message.
                     fRevertToHeaderProcessing = true;
                 }
             }
         } // cs_main
 
         if (fProcessBLOCKTXN) {
             return ProcessMessage(config, pfrom, NetMsgType::BLOCKTXN,
                                   blockTxnMsg, nTimeReceived, chainman, connman,
                                   banman, interruptMsgProc);
         }
 
         if (fRevertToHeaderProcessing) {
             // Headers received from HB compact block peers are permitted to be
             // relayed before full validation (see BIP 152), so we don't want to
             // disconnect the peer if the header turns out to be for an invalid
             // block. Note that if a peer tries to build on an invalid chain,
             // that will be detected and the peer will be banned.
             return ProcessHeadersMessage(config, pfrom, connman, chainman,
                                          {cmpctblock.header},
                                          /*via_compact_block=*/true);
         }
 
         if (fBlockReconstructed) {
             // If we got here, we were able to optimistically reconstruct a
             // block that is in flight from some other peer.
             {
                 LOCK(cs_main);
                 mapBlockSource.emplace(pblock->GetHash(),
                                        std::make_pair(pfrom.GetId(), false));
             }
             bool fNewBlock = false;
             // Setting fForceProcessing to true means that we bypass some of
             // our anti-DoS protections in AcceptBlock, which filters
             // unrequested blocks that might be trying to waste our resources
             // (eg disk space). Because we only try to reconstruct blocks when
             // we're close to caught up (via the CanDirectFetch() requirement
             // above, combined with the behavior of not requesting blocks until
             // we have a chain with at least nMinimumChainWork), and we ignore
             // compact blocks with less work than our tip, it is safe to treat
             // reconstructed compact blocks as having been requested.
             chainman.ProcessNewBlock(config, pblock, /*fForceProcessing=*/true,
                                      &fNewBlock);
             if (fNewBlock) {
                 pfrom.nLastBlockTime = GetTime();
             } else {
                 LOCK(cs_main);
                 mapBlockSource.erase(pblock->GetHash());
             }
 
             // hold cs_main for CBlockIndex::IsValid()
             LOCK(cs_main);
             if (pindex->IsValid(BlockValidity::TRANSACTIONS)) {
                 // Clear download state for this block, which is in process from
                 // some other peer. We do this after calling. ProcessNewBlock so
                 // that a malleated cmpctblock announcement can't be used to
                 // interfere with block relay.
                 MarkBlockAsReceived(pblock->GetHash());
             }
         }
         return true;
     }
 
     if (msg_type == NetMsgType::BLOCKTXN) {
         // Ignore blocktxn received while importing
         if (fImporting || fReindex) {
             LogPrint(BCLog::NET,
                      "Unexpected blocktxn message received from peer %d\n",
                      pfrom.GetId());
             return true;
         }
 
         BlockTransactions resp;
         vRecv >> resp;
 
         std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
         bool fBlockRead = false;
         {
             LOCK(cs_main);
 
             std::map<BlockHash,
                      std::pair<NodeId, std::list<QueuedBlock>::iterator>>::
                 iterator it = mapBlocksInFlight.find(resp.blockhash);
             if (it == mapBlocksInFlight.end() ||
                 !it->second.second->partialBlock ||
                 it->second.first != pfrom.GetId()) {
                 LogPrint(BCLog::NET,
                          "Peer %d sent us block transactions for block "
                          "we weren't expecting\n",
                          pfrom.GetId());
                 return true;
             }
 
             PartiallyDownloadedBlock &partialBlock =
                 *it->second.second->partialBlock;
             ReadStatus status = partialBlock.FillBlock(*pblock, resp.txn);
             if (status == READ_STATUS_INVALID) {
                 // Reset in-flight state in case of whitelist.
                 MarkBlockAsReceived(resp.blockhash);
                 Misbehaving(pfrom, 100, "invalid-cmpctblk-txns");
                 LogPrintf("Peer %d sent us invalid compact block/non-matching "
                           "block transactions\n",
                           pfrom.GetId());
                 return true;
             } else if (status == READ_STATUS_FAILED) {
                 // Might have collided, fall back to getdata now :(
                 std::vector<CInv> invs;
                 invs.push_back(CInv(MSG_BLOCK, resp.blockhash));
                 connman.PushMessage(&pfrom,
                                     msgMaker.Make(NetMsgType::GETDATA, invs));
             } else {
                 // Block is either okay, or possibly we received
                 // READ_STATUS_CHECKBLOCK_FAILED.
                 // Note that CheckBlock can only fail for one of a few reasons:
                 // 1. bad-proof-of-work (impossible here, because we've already
                 //    accepted the header)
                 // 2. merkleroot doesn't match the transactions given (already
                 //    caught in FillBlock with READ_STATUS_FAILED, so
                 //    impossible here)
                 // 3. the block is otherwise invalid (eg invalid coinbase,
                 //    block is too big, too many legacy sigops, etc).
                 // So if CheckBlock failed, #3 is the only possibility.
                 // Under BIP 152, we don't DoS-ban unless proof of work is
                 // invalid (we don't require all the stateless checks to have
                 // been run). This is handled below, so just treat this as
                 // though the block was successfully read, and rely on the
                 // handling in ProcessNewBlock to ensure the block index is
                 // updated, etc.
 
                 // it is now an empty pointer
                 MarkBlockAsReceived(resp.blockhash);
                 fBlockRead = true;
                 // mapBlockSource is used for potentially punishing peers and
                 // updating which peers send us compact blocks, so the race
                 // between here and cs_main in ProcessNewBlock is fine.
                 // BIP 152 permits peers to relay compact blocks after
                 // validating the header only; we should not punish peers
                 // if the block turns out to be invalid.
                 mapBlockSource.emplace(resp.blockhash,
                                        std::make_pair(pfrom.GetId(), false));
             }
         } // Don't hold cs_main when we call into ProcessNewBlock
         if (fBlockRead) {
             bool fNewBlock = false;
             // Since we requested this block (it was in mapBlocksInFlight),
             // force it to be processed, even if it would not be a candidate for
             // new tip (missing previous block, chain not long enough, etc)
             // This bypasses some anti-DoS logic in AcceptBlock (eg to prevent
             // disk-space attacks), but this should be safe due to the
             // protections in the compact block handler -- see related comment
             // in compact block optimistic reconstruction handling.
             chainman.ProcessNewBlock(config, pblock, /*fForceProcessing=*/true,
                                      &fNewBlock);
             if (fNewBlock) {
                 pfrom.nLastBlockTime = GetTime();
             } else {
                 LOCK(cs_main);
                 mapBlockSource.erase(pblock->GetHash());
             }
         }
         return true;
     }
 
     if (msg_type == NetMsgType::HEADERS) {
         // Ignore headers received while importing
         if (fImporting || fReindex) {
             LogPrint(BCLog::NET,
                      "Unexpected headers message received from peer %d\n",
                      pfrom.GetId());
             return true;
         }
 
         std::vector<CBlockHeader> headers;
 
         // Bypass the normal CBlock deserialization, as we don't want to risk
         // deserializing 2000 full blocks.
         unsigned int nCount = ReadCompactSize(vRecv);
         if (nCount > MAX_HEADERS_RESULTS) {
             LOCK(cs_main);
             Misbehaving(pfrom, 20, "too-many-headers");
             return error("headers message size = %u", nCount);
         }
         headers.resize(nCount);
         for (unsigned int n = 0; n < nCount; n++) {
             vRecv >> headers[n];
             // Ignore tx count; assume it is 0.
             ReadCompactSize(vRecv);
         }
 
         return ProcessHeadersMessage(config, pfrom, connman, chainman, headers,
                                      /*via_compact_block=*/false);
     }
 
     if (msg_type == NetMsgType::BLOCK) {
         // Ignore block received while importing
         if (fImporting || fReindex) {
             LogPrint(BCLog::NET,
                      "Unexpected block message received from peer %d\n",
                      pfrom.GetId());
             return true;
         }
 
         std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
         vRecv >> *pblock;
 
         LogPrint(BCLog::NET, "received block %s peer=%d\n",
                  pblock->GetHash().ToString(), pfrom.GetId());
 
         // Process all blocks from whitelisted peers, even if not requested,
         // unless we're still syncing with the network. Such an unrequested
         // block may still be processed, subject to the conditions in
         // AcceptBlock().
         bool forceProcessing = pfrom.HasPermission(PF_NOBAN) &&
                                !::ChainstateActive().IsInitialBlockDownload();
         const BlockHash hash = pblock->GetHash();
         {
             LOCK(cs_main);
             // Also always process if we requested the block explicitly, as we
             // may need it even though it is not a candidate for a new best tip.
             forceProcessing |= MarkBlockAsReceived(hash);
             // mapBlockSource is only used for punishing peers and setting
             // which peers send us compact blocks, so the race between here and
             // cs_main in ProcessNewBlock is fine.
             mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true));
         }
         bool fNewBlock = false;
         chainman.ProcessNewBlock(config, pblock, forceProcessing, &fNewBlock);
         if (fNewBlock) {
             pfrom.nLastBlockTime = GetTime();
         } else {
             LOCK(cs_main);
             mapBlockSource.erase(hash);
         }
         return true;
     }
 
     // Ignore avalanche requests while importing
     if (msg_type == NetMsgType::AVAPOLL && !fImporting && !fReindex &&
         g_avalanche &&
         gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
         auto now = std::chrono::steady_clock::now();
         int64_t cooldown =
             gArgs.GetArg("-avacooldown", AVALANCHE_DEFAULT_COOLDOWN);
 
         {
             LOCK(cs_main);
             auto &node_state = State(pfrom.GetId())->m_avalanche_state;
 
             if (now <
                 node_state.last_poll + std::chrono::milliseconds(cooldown)) {
                 Misbehaving(pfrom, 20, "avapool-cooldown");
             }
 
             node_state.last_poll = now;
         }
 
         uint64_t round;
         Unserialize(vRecv, round);
 
         unsigned int nCount = ReadCompactSize(vRecv);
         if (nCount > AVALANCHE_MAX_ELEMENT_POLL) {
             LOCK(cs_main);
             Misbehaving(pfrom, 20, "too-many-ava-poll");
             return error("poll message size = %u", nCount);
         }
 
         std::vector<avalanche::Vote> votes;
         votes.reserve(nCount);
 
         LogPrint(BCLog::NET, "received avalanche poll from peer=%d\n",
                  pfrom.GetId());
 
         {
             LOCK(cs_main);
 
             for (unsigned int n = 0; n < nCount; n++) {
                 CInv inv;
                 vRecv >> inv;
 
                 const auto insertVote = [&](uint32_t e) {
                     votes.emplace_back(e, inv.hash);
                 };
 
                 // Not a block.
                 if (inv.type != MSG_BLOCK) {
                     insertVote(-1);
                     continue;
                 }
 
                 // We have a block.
                 const CBlockIndex *pindex =
                     LookupBlockIndex(BlockHash(inv.hash));
 
                 // Unknown block.
                 if (!pindex) {
                     insertVote(-1);
                     continue;
                 }
 
                 // Invalid block
                 if (pindex->nStatus.isInvalid()) {
                     insertVote(1);
                     continue;
                 }
 
                 // Parked block
                 if (pindex->nStatus.isOnParkedChain()) {
                     insertVote(2);
                     continue;
                 }
 
                 const CBlockIndex *pindexTip = ::ChainActive().Tip();
                 const CBlockIndex *pindexFork =
                     LastCommonAncestor(pindex, pindexTip);
 
                 // Active block.
                 if (pindex == pindexFork) {
                     insertVote(0);
                     continue;
                 }
 
                 // Fork block.
                 if (pindexFork != pindexTip) {
                     insertVote(3);
                     continue;
                 }
 
                 // Missing block data.
                 if (!pindex->nStatus.hasData()) {
                     insertVote(-2);
                     continue;
                 }
 
                 // This block is built on top of the tip, we have the data, it
                 // is pending connection or rejection.
                 insertVote(-3);
             }
         }
 
         // Send the query to the node.
         g_avalanche->sendResponse(
             &pfrom, avalanche::Response(round, cooldown, std::move(votes)));
         return true;
     }
 
     // Ignore avalanche requests while importing
     if (msg_type == NetMsgType::AVARESPONSE && !fImporting && !fReindex &&
         g_avalanche &&
         gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
         // As long as QUIC is not implemented, we need to sign response and
         // verify response's signatures in order to avoid any manipulation of
         // messages at the transport level.
         CHashVerifier<CDataStream> verifier(&vRecv);
         avalanche::Response response;
         verifier >> response;
 
         if (!g_avalanche->forNode(pfrom.GetId(), [&](const avalanche::Node &n) {
                 std::array<uint8_t, 64> sig;
                 vRecv >> sig;
-
-                // Unfortunately, the verify API require a vector.
-                std::vector<uint8_t> vchSig{sig.begin(), sig.end()};
-                return n.pubkey.VerifySchnorr(verifier.GetHash(), vchSig);
+                return n.pubkey.VerifySchnorr(verifier.GetHash(), sig);
             })) {
             LOCK(cs_main);
             Misbehaving(pfrom, 100, "invalid-ava-response-signature");
             return true;
         }
 
         std::vector<avalanche::BlockUpdate> updates;
         if (!g_avalanche->registerVotes(pfrom.GetId(), response, updates)) {
             return true;
         }
 
         if (updates.size()) {
             for (avalanche::BlockUpdate &u : updates) {
                 CBlockIndex *pindex = u.getBlockIndex();
                 switch (u.getStatus()) {
                     case avalanche::BlockUpdate::Status::Invalid:
                     case avalanche::BlockUpdate::Status::Rejected: {
                         LogPrintf("Avalanche rejected %s, parking\n",
                                   pindex->GetBlockHash().GetHex());
                         BlockValidationState state;
                         ::ChainstateActive().ParkBlock(config, state, pindex);
                         if (!state.IsValid()) {
                             return error("Database error: %s",
                                          state.GetRejectReason());
                         }
                     } break;
                     case avalanche::BlockUpdate::Status::Accepted:
                     case avalanche::BlockUpdate::Status::Finalized: {
                         LogPrintf("Avalanche accepted %s\n",
                                   pindex->GetBlockHash().GetHex());
                         LOCK(cs_main);
                         UnparkBlock(pindex);
                     } break;
                 }
             }
 
             BlockValidationState state;
             if (!ActivateBestChain(config, state)) {
                 LogPrint(BCLog::NET, "failed to activate chain (%s)\n",
                          state.ToString());
             }
         }
 
         return true;
     }
 
     if (msg_type == NetMsgType::GETADDR) {
         // 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 nodes which are behind NAT and can
         // only make outgoing connections ignore the getaddr message mitigates
         // the attack.
         if (!pfrom.fInbound) {
             LogPrint(BCLog::NET,
                      "Ignoring \"getaddr\" from outbound connection. peer=%d\n",
                      pfrom.GetId());
             return true;
         }
         if (!pfrom.IsAddrRelayPeer()) {
             LogPrint(BCLog::NET,
                      "Ignoring \"getaddr\" from block-relay-only connection. "
                      "peer=%d\n",
                      pfrom.GetId());
             return true;
         }
 
         // Only send one GetAddr response per connection to reduce resource
         // waste and discourage addr stamping of INV announcements.
         if (pfrom.fSentAddr) {
             LogPrint(BCLog::NET, "Ignoring repeated \"getaddr\". peer=%d\n",
                      pfrom.GetId());
             return true;
         }
         pfrom.fSentAddr = true;
 
         pfrom.vAddrToSend.clear();
         std::vector<CAddress> vAddr = connman.GetAddresses();
         FastRandomContext insecure_rand;
         for (const CAddress &addr : vAddr) {
             if (!banman->IsDiscouraged(addr) && !banman->IsBanned(addr)) {
                 pfrom.PushAddress(addr, insecure_rand);
             }
         }
         return true;
     }
 
     if (msg_type == NetMsgType::MEMPOOL) {
         if (!(pfrom.GetLocalServices() & NODE_BLOOM) &&
             !pfrom.HasPermission(PF_MEMPOOL)) {
             if (!pfrom.HasPermission(PF_NOBAN)) {
                 LogPrint(BCLog::NET,
                          "mempool request with bloom filters disabled, "
                          "disconnect peer=%d\n",
                          pfrom.GetId());
                 pfrom.fDisconnect = true;
             }
             return true;
         }
 
         if (connman.OutboundTargetReached(false) &&
             !pfrom.HasPermission(PF_MEMPOOL)) {
             if (!pfrom.HasPermission(PF_NOBAN)) {
                 LogPrint(BCLog::NET,
                          "mempool request with bandwidth limit reached, "
                          "disconnect peer=%d\n",
                          pfrom.GetId());
                 pfrom.fDisconnect = true;
             }
             return true;
         }
 
         if (pfrom.m_tx_relay != nullptr) {
             LOCK(pfrom.m_tx_relay->cs_tx_inventory);
             pfrom.m_tx_relay->fSendMempool = true;
         }
         return true;
     }
 
     if (msg_type == NetMsgType::PING) {
         if (pfrom.nVersion > BIP0031_VERSION) {
             uint64_t nonce = 0;
             vRecv >> nonce;
             // Echo the message back with the nonce. This allows for two useful
             // features:
             //
             // 1) A remote node can quickly check if the connection is
             // operational.
             // 2) Remote nodes can measure the latency of the network thread. If
             // this node is overloaded it won't respond to pings quickly and the
             // remote node can avoid sending us more work, like chain download
             // requests.
             //
             // The nonce stops the remote getting confused between different
             // pings: without it, if the remote node sends a ping once per
             // second and this node takes 5 seconds to respond to each, the 5th
             // ping the remote sends would appear to return very quickly.
             connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::PONG, nonce));
         }
         return true;
     }
 
     if (msg_type == NetMsgType::PONG) {
         int64_t pingUsecEnd = nTimeReceived;
         uint64_t nonce = 0;
         size_t nAvail = vRecv.in_avail();
         bool bPingFinished = false;
         std::string sProblem;
 
         if (nAvail >= sizeof(nonce)) {
             vRecv >> nonce;
 
             // Only process pong message if there is an outstanding ping (old
             // ping without nonce should never pong)
             if (pfrom.nPingNonceSent != 0) {
                 if (nonce == pfrom.nPingNonceSent) {
                     // Matching pong received, this ping is no longer
                     // outstanding
                     bPingFinished = true;
                     int64_t pingUsecTime = pingUsecEnd - pfrom.nPingUsecStart;
                     if (pingUsecTime > 0) {
                         // Successful ping time measurement, replace previous
                         pfrom.nPingUsecTime = pingUsecTime;
                         pfrom.nMinPingUsecTime = std::min(
                             pfrom.nMinPingUsecTime.load(), pingUsecTime);
                     } else {
                         // This should never happen
                         sProblem = "Timing mishap";
                     }
                 } else {
                     // 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
                         bPingFinished = true;
                         sProblem = "Nonce zero";
                     }
                 }
             } else {
                 sProblem = "Unsolicited pong without ping";
             }
         } else {
             // This is most likely a bug in another implementation somewhere;
             // cancel this ping
             bPingFinished = true;
             sProblem = "Short payload";
         }
 
         if (!(sProblem.empty())) {
             LogPrint(BCLog::NET,
                      "pong peer=%d: %s, %x expected, %x received, %u bytes\n",
                      pfrom.GetId(), sProblem, pfrom.nPingNonceSent, nonce,
                      nAvail);
         }
         if (bPingFinished) {
             pfrom.nPingNonceSent = 0;
         }
         return true;
     }
 
     if (msg_type == NetMsgType::FILTERLOAD) {
         CBloomFilter filter;
         vRecv >> filter;
 
         if (!filter.IsWithinSizeConstraints()) {
             // There is no excuse for sending a too-large filter
             LOCK(cs_main);
             Misbehaving(pfrom, 100, "oversized-bloom-filter");
         } else if (pfrom.m_tx_relay != nullptr) {
             LOCK(pfrom.m_tx_relay->cs_filter);
             pfrom.m_tx_relay->pfilter.reset(new CBloomFilter(filter));
             pfrom.m_tx_relay->pfilter->UpdateEmptyFull();
             pfrom.m_tx_relay->fRelayTxes = true;
         }
         return true;
     }
 
     if (msg_type == NetMsgType::FILTERADD) {
         std::vector<uint8_t> vData;
         vRecv >> vData;
 
         // Nodes must NEVER send a data item > 520 bytes (the max size for a
         // script data object, and thus, the maximum size any matched object can
         // have) in a filteradd message.
         bool bad = false;
         if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) {
             bad = true;
         } else if (pfrom.m_tx_relay != nullptr) {
             LOCK(pfrom.m_tx_relay->cs_filter);
             if (pfrom.m_tx_relay->pfilter) {
                 pfrom.m_tx_relay->pfilter->insert(vData);
             } else {
                 bad = true;
             }
         }
         if (bad) {
             LOCK(cs_main);
             // The structure of this code doesn't really allow for a good error
             // code. We'll go generic.
             Misbehaving(pfrom, 100, "invalid-filteradd");
         }
         return true;
     }
 
     if (msg_type == NetMsgType::FILTERCLEAR) {
         if (pfrom.m_tx_relay == nullptr) {
             return true;
         }
         LOCK(pfrom.m_tx_relay->cs_filter);
         if (pfrom.GetLocalServices() & NODE_BLOOM) {
             pfrom.m_tx_relay->pfilter.reset(new CBloomFilter());
         }
         pfrom.m_tx_relay->fRelayTxes = true;
         return true;
     }
 
     if (msg_type == NetMsgType::FEEFILTER) {
         Amount newFeeFilter = Amount::zero();
         vRecv >> newFeeFilter;
         if (MoneyRange(newFeeFilter)) {
             if (pfrom.m_tx_relay != nullptr) {
                 LOCK(pfrom.m_tx_relay->cs_feeFilter);
                 pfrom.m_tx_relay->minFeeFilter = newFeeFilter;
             }
             LogPrint(BCLog::NET, "received: feefilter of %s from peer=%d\n",
                      CFeeRate(newFeeFilter).ToString(), pfrom.GetId());
         }
         return true;
     }
 
     if (msg_type == NetMsgType::GETCFILTERS) {
         ProcessGetCFilters(pfrom, vRecv, chainparams, connman);
         return true;
     }
 
     if (msg_type == NetMsgType::GETCFHEADERS) {
         ProcessGetCFHeaders(pfrom, vRecv, chainparams, connman);
         return true;
     }
 
     if (msg_type == NetMsgType::GETCFCHECKPT) {
         ProcessGetCFCheckPt(pfrom, vRecv, chainparams, connman);
         return true;
     }
 
     if (msg_type == NetMsgType::NOTFOUND) {
         // Remove the NOTFOUND transactions from the peer
         LOCK(cs_main);
         CNodeState *state = State(pfrom.GetId());
         std::vector<CInv> vInv;
         vRecv >> vInv;
         if (vInv.size() <=
             MAX_PEER_TX_IN_FLIGHT + MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
             for (CInv &inv : vInv) {
                 if (inv.type == MSG_TX) {
                     const TxId txid(inv.hash);
                     // If we receive a NOTFOUND message for a txid we requested,
                     // erase it from our data structures for this peer.
                     auto in_flight_it =
                         state->m_tx_download.m_tx_in_flight.find(txid);
                     if (in_flight_it ==
                         state->m_tx_download.m_tx_in_flight.end()) {
                         // Skip any further work if this is a spurious NOTFOUND
                         // message.
                         continue;
                     }
                     state->m_tx_download.m_tx_in_flight.erase(in_flight_it);
                     state->m_tx_download.m_tx_announced.erase(txid);
                 }
             }
         }
         return true;
     }
 
     // Ignore unknown commands for extensibility
     LogPrint(BCLog::NET, "Unknown command \"%s\" from peer=%d\n",
              SanitizeString(msg_type), pfrom.GetId());
     return true;
 }
 
 bool PeerLogicValidation::CheckIfBanned(CNode &pnode) {
     AssertLockHeld(cs_main);
     CNodeState &state = *State(pnode.GetId());
 
     if (state.m_should_discourage) {
         state.m_should_discourage = false;
         if (pnode.HasPermission(PF_NOBAN)) {
             LogPrintf("Warning: not punishing whitelisted peer %s!\n",
                       pnode.addr.ToString());
         } else if (pnode.m_manual_connection) {
             LogPrintf("Warning: not punishing manually-connected peer %s!\n",
                       pnode.addr.ToString());
         } else if (pnode.addr.IsLocal()) {
             // Disconnect but don't discourage this local node
             LogPrintf(
                 "Warning: disconnecting but not discouraging local peer %s!\n",
                 pnode.addr.ToString());
             pnode.fDisconnect = true;
         } else {
             // Disconnect and discourage all nodes sharing the address
             LogPrintf("Disconnecting and discouraging peer %s!\n",
                       pnode.addr.ToString());
             if (m_banman) {
                 m_banman->Discourage(pnode.addr);
             }
             connman->DisconnectNode(pnode.addr);
         }
         return true;
     }
     return false;
 }
 
 bool PeerLogicValidation::ProcessMessages(const Config &config, CNode *pfrom,
                                           std::atomic<bool> &interruptMsgProc) {
     //
     // Message format
     //  (4) message start
     //  (12) command
     //  (4) size
     //  (4) checksum
     //  (x) data
     //
     bool fMoreWork = false;
 
     if (!pfrom->vRecvGetData.empty()) {
         ProcessGetData(config, *pfrom, *connman, interruptMsgProc);
     }
 
     if (!pfrom->orphan_work_set.empty()) {
         LOCK2(cs_main, g_cs_orphans);
         ProcessOrphanTx(config, *connman, pfrom->orphan_work_set);
     }
 
     if (pfrom->fDisconnect) {
         return false;
     }
 
     // this maintains the order of responses and prevents vRecvGetData from
     // growing unbounded
     if (!pfrom->vRecvGetData.empty()) {
         return true;
     }
     if (!pfrom->orphan_work_set.empty()) {
         return true;
     }
 
     // Don't bother if send buffer is too full to respond anyway
     if (pfrom->fPauseSend) {
         return false;
     }
 
     std::list<CNetMessage> msgs;
     {
         LOCK(pfrom->cs_vProcessMsg);
         if (pfrom->vProcessMsg.empty()) {
             return false;
         }
         // Just take one message
         msgs.splice(msgs.begin(), pfrom->vProcessMsg,
                     pfrom->vProcessMsg.begin());
         pfrom->nProcessQueueSize -= msgs.front().m_raw_message_size;
         pfrom->fPauseRecv =
             pfrom->nProcessQueueSize > connman->GetReceiveFloodSize();
         fMoreWork = !pfrom->vProcessMsg.empty();
     }
     CNetMessage &msg(msgs.front());
 
     msg.SetVersion(pfrom->GetRecvVersion());
 
     // Check network magic
     if (!msg.m_valid_netmagic) {
         LogPrint(BCLog::NET,
                  "PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%d\n",
                  SanitizeString(msg.m_command), pfrom->GetId());
 
         // Make sure we discourage where that come from for some time.
         if (m_banman) {
             m_banman->Discourage(pfrom->addr);
         }
         connman->DisconnectNode(pfrom->addr);
 
         pfrom->fDisconnect = true;
         return false;
     }
 
     // Check header
     if (!msg.m_valid_header) {
         LogPrint(BCLog::NET, "PROCESSMESSAGE: ERRORS IN HEADER %s peer=%d\n",
                  SanitizeString(msg.m_command), pfrom->GetId());
         return fMoreWork;
     }
     const std::string &msg_type = msg.m_command;
 
     // Message size
     unsigned int nMessageSize = msg.m_message_size;
 
     // Checksum
     CDataStream &vRecv = msg.m_recv;
     if (!msg.m_valid_checksum) {
         LogPrint(BCLog::NET, "%s(%s, %u bytes): CHECKSUM ERROR peer=%d\n",
                  __func__, SanitizeString(msg_type), nMessageSize,
                  pfrom->GetId());
         if (m_banman) {
             m_banman->Discourage(pfrom->addr);
         }
         connman->DisconnectNode(pfrom->addr);
         return fMoreWork;
     }
 
     // Process message
     bool fRet = false;
     try {
         fRet = ProcessMessage(config, *pfrom, msg_type, vRecv, msg.m_time,
                               m_chainman, *connman, m_banman, interruptMsgProc);
         if (interruptMsgProc) {
             return false;
         }
 
         if (!pfrom->vRecvGetData.empty()) {
             fMoreWork = true;
         }
     } catch (const std::exception &e) {
         LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' (%s) caught\n",
                  __func__, SanitizeString(msg_type), nMessageSize, e.what(),
                  typeid(e).name());
     } catch (...) {
         LogPrint(BCLog::NET, "%s(%s, %u bytes): Unknown exception caught\n",
                  __func__, SanitizeString(msg_type), nMessageSize);
     }
 
     if (!fRet) {
         LogPrint(BCLog::NET, "%s(%s, %u bytes) FAILED peer=%d\n", __func__,
                  SanitizeString(msg_type), nMessageSize, pfrom->GetId());
     }
 
     LOCK(cs_main);
     CheckIfBanned(*pfrom);
 
     return fMoreWork;
 }
 
 void PeerLogicValidation::ConsiderEviction(CNode &pto,
                                            int64_t time_in_seconds) {
     AssertLockHeld(cs_main);
 
     CNodeState &state = *State(pto.GetId());
     const CNetMsgMaker msgMaker(pto.GetSendVersion());
 
     if (!state.m_chain_sync.m_protect &&
         IsOutboundDisconnectionCandidate(pto) && state.fSyncStarted) {
         // This is an outbound peer subject to disconnection if they don't
         // announce a block with as much work as the current tip within
         // CHAIN_SYNC_TIMEOUT + HEADERS_RESPONSE_TIME seconds (note: if their
         // chain has more work than ours, we should sync to it, unless it's
         // invalid, in which case we should find that out and disconnect from
         // them elsewhere).
         if (state.pindexBestKnownBlock != nullptr &&
             state.pindexBestKnownBlock->nChainWork >=
                 ::ChainActive().Tip()->nChainWork) {
             if (state.m_chain_sync.m_timeout != 0) {
                 state.m_chain_sync.m_timeout = 0;
                 state.m_chain_sync.m_work_header = nullptr;
                 state.m_chain_sync.m_sent_getheaders = false;
             }
         } else if (state.m_chain_sync.m_timeout == 0 ||
                    (state.m_chain_sync.m_work_header != nullptr &&
                     state.pindexBestKnownBlock != nullptr &&
                     state.pindexBestKnownBlock->nChainWork >=
                         state.m_chain_sync.m_work_header->nChainWork)) {
             // Our best block known by this peer is behind our tip, and we're
             // either noticing that for the first time, OR this peer was able to
             // catch up to some earlier point where we checked against our tip.
             // Either way, set a new timeout based on current tip.
             state.m_chain_sync.m_timeout = time_in_seconds + CHAIN_SYNC_TIMEOUT;
             state.m_chain_sync.m_work_header = ::ChainActive().Tip();
             state.m_chain_sync.m_sent_getheaders = false;
         } else if (state.m_chain_sync.m_timeout > 0 &&
                    time_in_seconds > state.m_chain_sync.m_timeout) {
             // No evidence yet that our peer has synced to a chain with work
             // equal to that of our tip, when we first detected it was behind.
             // Send a single getheaders message to give the peer a chance to
             // update us.
             if (state.m_chain_sync.m_sent_getheaders) {
                 // They've run out of time to catch up!
                 LogPrintf(
                     "Disconnecting outbound peer %d for old chain, best known "
                     "block = %s\n",
                     pto.GetId(),
                     state.pindexBestKnownBlock != nullptr
                         ? state.pindexBestKnownBlock->GetBlockHash().ToString()
                         : "<none>");
                 pto.fDisconnect = true;
             } else {
                 assert(state.m_chain_sync.m_work_header);
                 LogPrint(
                     BCLog::NET,
                     "sending getheaders to outbound peer=%d to verify chain "
                     "work (current best known block:%s, benchmark blockhash: "
                     "%s)\n",
                     pto.GetId(),
                     state.pindexBestKnownBlock != nullptr
                         ? state.pindexBestKnownBlock->GetBlockHash().ToString()
                         : "<none>",
                     state.m_chain_sync.m_work_header->GetBlockHash()
                         .ToString());
                 connman->PushMessage(
                     &pto,
                     msgMaker.Make(NetMsgType::GETHEADERS,
                                   ::ChainActive().GetLocator(
                                       state.m_chain_sync.m_work_header->pprev),
                                   uint256()));
                 state.m_chain_sync.m_sent_getheaders = true;
                 // 2 minutes
                 constexpr int64_t HEADERS_RESPONSE_TIME = 120;
                 // Bump the timeout to allow a response, which could clear the
                 // timeout (if the response shows the peer has synced), reset
                 // the timeout (if the peer syncs to the required work but not
                 // to our tip), or result in disconnect (if we advance to the
                 // timeout and pindexBestKnownBlock has not sufficiently
                 // progressed)
                 state.m_chain_sync.m_timeout =
                     time_in_seconds + HEADERS_RESPONSE_TIME;
             }
         }
     }
 }
 
 void PeerLogicValidation::EvictExtraOutboundPeers(int64_t time_in_seconds) {
     // Check whether we have too many outbound peers
     int extra_peers = connman->GetExtraOutboundCount();
     if (extra_peers <= 0) {
         return;
     }
 
     // If we have more outbound peers than we target, disconnect one.
     // Pick the outbound peer that least recently announced us a new block, with
     // ties broken by choosing the more recent connection (higher node id)
     NodeId worst_peer = -1;
     int64_t oldest_block_announcement = std::numeric_limits<int64_t>::max();
 
     connman->ForEachNode([&](CNode *pnode) {
         AssertLockHeld(cs_main);
 
         // Ignore non-outbound peers, or nodes marked for disconnect already
         if (!IsOutboundDisconnectionCandidate(*pnode) || pnode->fDisconnect) {
             return;
         }
         CNodeState *state = State(pnode->GetId());
         if (state == nullptr) {
             // shouldn't be possible, but just in case
             return;
         }
         // Don't evict our protected peers
         if (state->m_chain_sync.m_protect) {
             return;
         }
         // Don't evict our block-relay-only peers.
         if (pnode->m_tx_relay == nullptr) {
             return;
         }
 
         if (state->m_last_block_announcement < oldest_block_announcement ||
             (state->m_last_block_announcement == oldest_block_announcement &&
              pnode->GetId() > worst_peer)) {
             worst_peer = pnode->GetId();
             oldest_block_announcement = state->m_last_block_announcement;
         }
     });
 
     if (worst_peer == -1) {
         return;
     }
 
     bool disconnected = connman->ForNode(worst_peer, [&](CNode *pnode) {
         AssertLockHeld(cs_main);
 
         // Only disconnect a peer that has been connected to us for some
         // reasonable fraction of our check-frequency, to give it time for new
         // information to have arrived.
         // Also don't disconnect any peer we're trying to download a block from.
         CNodeState &state = *State(pnode->GetId());
         if (time_in_seconds - pnode->nTimeConnected > MINIMUM_CONNECT_TIME &&
             state.nBlocksInFlight == 0) {
             LogPrint(BCLog::NET,
                      "disconnecting extra outbound peer=%d (last block "
                      "announcement received at time %d)\n",
                      pnode->GetId(), oldest_block_announcement);
             pnode->fDisconnect = true;
             return true;
         } else {
             LogPrint(BCLog::NET,
                      "keeping outbound peer=%d chosen for eviction "
                      "(connect time: %d, blocks_in_flight: %d)\n",
                      pnode->GetId(), pnode->nTimeConnected,
                      state.nBlocksInFlight);
             return false;
         }
     });
 
     if (disconnected) {
         // If we disconnected an extra peer, that means we successfully
         // connected to at least one peer after the last time we detected a
         // stale tip. Don't try any more extra peers until we next detect a
         // stale tip, to limit the load we put on the network from these extra
         // connections.
         connman->SetTryNewOutboundPeer(false);
     }
 }
 
 void PeerLogicValidation::CheckForStaleTipAndEvictPeers(
     const Consensus::Params &consensusParams) {
     LOCK(cs_main);
 
     if (connman == nullptr) {
         return;
     }
 
     int64_t time_in_seconds = GetTime();
 
     EvictExtraOutboundPeers(time_in_seconds);
 
     if (time_in_seconds <= m_stale_tip_check_time) {
         return;
     }
 
     // Check whether our tip is stale, and if so, allow using an extra outbound
     // peer.
     if (!fImporting && !fReindex && connman->GetNetworkActive() &&
         connman->GetUseAddrmanOutgoing() && TipMayBeStale(consensusParams)) {
         LogPrintf("Potential stale tip detected, will try using extra outbound "
                   "peer (last tip update: %d seconds ago)\n",
                   time_in_seconds - g_last_tip_update);
         connman->SetTryNewOutboundPeer(true);
     } else if (connman->GetTryNewOutboundPeer()) {
         connman->SetTryNewOutboundPeer(false);
     }
     m_stale_tip_check_time = time_in_seconds + STALE_CHECK_INTERVAL;
 }
 
 namespace {
 class CompareInvMempoolOrder {
     CTxMemPool *mp;
 
 public:
     explicit CompareInvMempoolOrder(CTxMemPool *_mempool) { mp = _mempool; }
 
     bool operator()(std::set<TxId>::iterator a, std::set<TxId>::iterator b) {
         /**
          * As std::make_heap produces a max-heap, we want the entries with the
          * fewest ancestors/highest fee to sort later.
          */
         return mp->CompareDepthAndScore(*b, *a);
     }
 };
 } // namespace
 
 bool PeerLogicValidation::SendMessages(const Config &config, CNode *pto,
                                        std::atomic<bool> &interruptMsgProc) {
     const Consensus::Params &consensusParams =
         config.GetChainParams().GetConsensus();
 
     // Don't send anything until the version handshake is complete
     if (!pto->fSuccessfullyConnected || pto->fDisconnect) {
         return true;
     }
 
     // If we get here, the outgoing message serialization version is set and
     // can't change.
     const CNetMsgMaker msgMaker(pto->GetSendVersion());
 
     //
     // Message: ping
     //
     bool pingSend = false;
     if (pto->fPingQueued) {
         // RPC ping request by user
         pingSend = true;
     }
     if (pto->nPingNonceSent == 0 &&
         pto->nPingUsecStart + PING_INTERVAL * 1000000 < GetTimeMicros()) {
         // Ping automatically sent as a latency probe & keepalive.
         pingSend = true;
     }
     if (pingSend) {
         uint64_t nonce = 0;
         while (nonce == 0) {
             GetRandBytes((uint8_t *)&nonce, sizeof(nonce));
         }
         pto->fPingQueued = false;
         pto->nPingUsecStart = GetTimeMicros();
         if (pto->nVersion > BIP0031_VERSION) {
             pto->nPingNonceSent = nonce;
             connman->PushMessage(pto, msgMaker.Make(NetMsgType::PING, nonce));
         } else {
             // Peer is too old to support ping command with nonce, pong will
             // never arrive.
             pto->nPingNonceSent = 0;
             connman->PushMessage(pto, msgMaker.Make(NetMsgType::PING));
         }
     }
 
     TRY_LOCK(cs_main, lockMain);
     if (!lockMain) {
         return true;
     }
 
     if (CheckIfBanned(*pto)) {
         return true;
     }
     CNodeState &state = *State(pto->GetId());
 
     // Address refresh broadcast
     int64_t nNow = GetTimeMicros();
     auto current_time = GetTime<std::chrono::microseconds>();
 
     if (pto->IsAddrRelayPeer() &&
         !::ChainstateActive().IsInitialBlockDownload() &&
         pto->m_next_local_addr_send < current_time) {
         AdvertiseLocal(pto);
         pto->m_next_local_addr_send =
             PoissonNextSend(current_time, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL);
     }
 
     //
     // Message: addr
     //
     if (pto->IsAddrRelayPeer() && pto->m_next_addr_send < current_time) {
         pto->m_next_addr_send =
             PoissonNextSend(current_time, AVG_ADDRESS_BROADCAST_INTERVAL);
         std::vector<CAddress> vAddr;
         vAddr.reserve(pto->vAddrToSend.size());
         assert(pto->m_addr_known);
         for (const CAddress &addr : pto->vAddrToSend) {
             if (!pto->m_addr_known->contains(addr.GetKey())) {
                 pto->m_addr_known->insert(addr.GetKey());
                 vAddr.push_back(addr);
                 // receiver rejects addr messages larger than 1000
                 if (vAddr.size() >= 1000) {
                     connman->PushMessage(
                         pto, msgMaker.Make(NetMsgType::ADDR, vAddr));
                     vAddr.clear();
                 }
             }
         }
         pto->vAddrToSend.clear();
         if (!vAddr.empty()) {
             connman->PushMessage(pto, msgMaker.Make(NetMsgType::ADDR, vAddr));
         }
 
         // we only send the big addr message once
         if (pto->vAddrToSend.capacity() > 40) {
             pto->vAddrToSend.shrink_to_fit();
         }
     }
 
     // Start block sync
     if (pindexBestHeader == nullptr) {
         pindexBestHeader = ::ChainActive().Tip();
     }
 
     // Download if this is a nice peer, or we have no nice peers and this one
     // might do.
     bool fFetch = state.fPreferredDownload ||
                   (nPreferredDownload == 0 && !pto->fClient && !pto->fOneShot);
 
     if (!state.fSyncStarted && !pto->fClient && !fImporting && !fReindex) {
         // Only actively request headers from a single peer, unless we're close
         // to today.
         if ((nSyncStarted == 0 && fFetch) ||
             pindexBestHeader->GetBlockTime() >
                 GetAdjustedTime() - 24 * 60 * 60) {
             state.fSyncStarted = true;
             state.nHeadersSyncTimeout =
                 GetTimeMicros() + HEADERS_DOWNLOAD_TIMEOUT_BASE +
                 HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER *
                     (GetAdjustedTime() - pindexBestHeader->GetBlockTime()) /
                     (consensusParams.nPowTargetSpacing);
             nSyncStarted++;
             const CBlockIndex *pindexStart = pindexBestHeader;
             /**
              * If possible, start at the block preceding the currently best
              * known header. This ensures that we always get a non-empty list of
              * headers back as long as the peer is up-to-date. With a non-empty
              * response, we can initialise the peer's known best block. This
              * wouldn't be possible if we requested starting at pindexBestHeader
              * and got back an empty response.
              */
             if (pindexStart->pprev) {
                 pindexStart = pindexStart->pprev;
             }
 
             LogPrint(BCLog::NET,
                      "initial getheaders (%d) to peer=%d (startheight:%d)\n",
                      pindexStart->nHeight, pto->GetId(), pto->nStartingHeight);
             connman->PushMessage(
                 pto, msgMaker.Make(NetMsgType::GETHEADERS,
                                    ::ChainActive().GetLocator(pindexStart),
                                    uint256()));
         }
     }
 
     //
     // Try sending block announcements via headers
     //
     {
         // If we have less than MAX_BLOCKS_TO_ANNOUNCE in our list of block
         // hashes we're relaying, and our peer wants headers announcements, then
         // find the first header not yet known to our peer but would connect,
         // and send. If no header would connect, or if we have too many blocks,
         // or if the peer doesn't want headers, just add all to the inv queue.
         LOCK(pto->cs_inventory);
         std::vector<CBlock> vHeaders;
         bool fRevertToInv =
             ((!state.fPreferHeaders &&
               (!state.fPreferHeaderAndIDs ||
                pto->vBlockHashesToAnnounce.size() > 1)) ||
              pto->vBlockHashesToAnnounce.size() > MAX_BLOCKS_TO_ANNOUNCE);
         // last header queued for delivery
         const CBlockIndex *pBestIndex = nullptr;
         // ensure pindexBestKnownBlock is up-to-date
         ProcessBlockAvailability(pto->GetId());
 
         if (!fRevertToInv) {
             bool fFoundStartingHeader = false;
             // Try to find first header that our peer doesn't have, and then
             // send all headers past that one. If we come across an headers that
             // aren't on ::ChainActive(), give up.
             for (const BlockHash &hash : pto->vBlockHashesToAnnounce) {
                 const CBlockIndex *pindex = LookupBlockIndex(hash);
                 assert(pindex);
                 if (::ChainActive()[pindex->nHeight] != pindex) {
                     // Bail out if we reorged away from this block
                     fRevertToInv = true;
                     break;
                 }
                 if (pBestIndex != nullptr && pindex->pprev != pBestIndex) {
                     // This means that the list of blocks to announce don't
                     // connect to each other. This shouldn't really be possible
                     // to hit during regular operation (because reorgs should
                     // take us to a chain that has some block not on the prior
                     // chain, which should be caught by the prior check), but
                     // one way this could happen is by using invalidateblock /
                     // reconsiderblock repeatedly on the tip, causing it to be
                     // added multiple times to vBlockHashesToAnnounce. Robustly
                     // deal with this rare situation by reverting to an inv.
                     fRevertToInv = true;
                     break;
                 }
                 pBestIndex = pindex;
                 if (fFoundStartingHeader) {
                     // add this to the headers message
                     vHeaders.push_back(pindex->GetBlockHeader());
                 } else if (PeerHasHeader(&state, pindex)) {
                     // Keep looking for the first new block.
                     continue;
                 } else if (pindex->pprev == nullptr ||
                            PeerHasHeader(&state, pindex->pprev)) {
                     // Peer doesn't have this header but they do have the prior
                     // one.
                     // Start sending headers.
                     fFoundStartingHeader = true;
                     vHeaders.push_back(pindex->GetBlockHeader());
                 } else {
                     // Peer doesn't have this header or the prior one --
                     // nothing will connect, so bail out.
                     fRevertToInv = true;
                     break;
                 }
             }
         }
         if (!fRevertToInv && !vHeaders.empty()) {
             if (vHeaders.size() == 1 && state.fPreferHeaderAndIDs) {
                 // We only send up to 1 block as header-and-ids, as otherwise
                 // probably means we're doing an initial-ish-sync or they're
                 // slow.
                 LogPrint(BCLog::NET,
                          "%s sending header-and-ids %s to peer=%d\n", __func__,
                          vHeaders.front().GetHash().ToString(), pto->GetId());
 
                 int nSendFlags = 0;
 
                 bool fGotBlockFromCache = false;
                 {
                     LOCK(cs_most_recent_block);
                     if (most_recent_block_hash == pBestIndex->GetBlockHash()) {
                         CBlockHeaderAndShortTxIDs cmpctblock(
                             *most_recent_block);
                         connman->PushMessage(
                             pto,
                             msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK,
                                           cmpctblock));
                         fGotBlockFromCache = true;
                     }
                 }
                 if (!fGotBlockFromCache) {
                     CBlock block;
                     bool ret =
                         ReadBlockFromDisk(block, pBestIndex, consensusParams);
                     assert(ret);
                     CBlockHeaderAndShortTxIDs cmpctblock(block);
                     connman->PushMessage(
                         pto, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK,
                                            cmpctblock));
                 }
                 state.pindexBestHeaderSent = pBestIndex;
             } else if (state.fPreferHeaders) {
                 if (vHeaders.size() > 1) {
                     LogPrint(BCLog::NET,
                              "%s: %u headers, range (%s, %s), to peer=%d\n",
                              __func__, vHeaders.size(),
                              vHeaders.front().GetHash().ToString(),
                              vHeaders.back().GetHash().ToString(),
                              pto->GetId());
                 } else {
                     LogPrint(BCLog::NET, "%s: sending header %s to peer=%d\n",
                              __func__, vHeaders.front().GetHash().ToString(),
                              pto->GetId());
                 }
                 connman->PushMessage(
                     pto, msgMaker.Make(NetMsgType::HEADERS, vHeaders));
                 state.pindexBestHeaderSent = pBestIndex;
             } else {
                 fRevertToInv = true;
             }
         }
         if (fRevertToInv) {
             // If falling back to using an inv, just try to inv the tip. The
             // last entry in vBlockHashesToAnnounce was our tip at some point in
             // the past.
             if (!pto->vBlockHashesToAnnounce.empty()) {
                 const BlockHash &hashToAnnounce =
                     pto->vBlockHashesToAnnounce.back();
                 const CBlockIndex *pindex = LookupBlockIndex(hashToAnnounce);
                 assert(pindex);
 
                 // Warn if we're announcing a block that is not on the main
                 // chain. This should be very rare and could be optimized out.
                 // Just log for now.
                 if (::ChainActive()[pindex->nHeight] != pindex) {
                     LogPrint(BCLog::NET,
                              "Announcing block %s not on main chain (tip=%s)\n",
                              hashToAnnounce.ToString(),
                              ::ChainActive().Tip()->GetBlockHash().ToString());
                 }
 
                 // If the peer's chain has this block, don't inv it back.
                 if (!PeerHasHeader(&state, pindex)) {
                     pto->PushInventory(CInv(MSG_BLOCK, hashToAnnounce));
                     LogPrint(BCLog::NET, "%s: sending inv peer=%d hash=%s\n",
                              __func__, pto->GetId(), hashToAnnounce.ToString());
                 }
             }
         }
         pto->vBlockHashesToAnnounce.clear();
     }
 
     //
     // Message: inventory
     //
     std::vector<CInv> vInv;
     {
         LOCK(pto->cs_inventory);
         vInv.reserve(std::max<size_t>(pto->vInventoryBlockToSend.size(),
                                       INVENTORY_BROADCAST_MAX_PER_MB *
                                           config.GetMaxBlockSize() / 1000000));
 
         // Add blocks
         for (const BlockHash &hash : pto->vInventoryBlockToSend) {
             vInv.push_back(CInv(MSG_BLOCK, hash));
             if (vInv.size() == MAX_INV_SZ) {
                 connman->PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
                 vInv.clear();
             }
         }
         pto->vInventoryBlockToSend.clear();
 
         if (pto->m_tx_relay != nullptr) {
             LOCK(pto->m_tx_relay->cs_tx_inventory);
             // Check whether periodic sends should happen
             bool fSendTrickle = pto->HasPermission(PF_NOBAN);
             if (pto->m_tx_relay->nNextInvSend < current_time) {
                 fSendTrickle = true;
                 if (pto->fInbound) {
                     pto->m_tx_relay->nNextInvSend = std::chrono::microseconds{
                         connman->PoissonNextSendInbound(
                             nNow, INVENTORY_BROADCAST_INTERVAL)};
                 } else {
                     // Skip delay for outbound peers, as there is less
                     // privacy concern for them.
                     pto->m_tx_relay->nNextInvSend = current_time;
                 }
             }
 
             // Time to send but the peer has requested we not relay
             // transactions.
             if (fSendTrickle) {
                 LOCK(pto->m_tx_relay->cs_filter);
                 if (!pto->m_tx_relay->fRelayTxes) {
                     pto->m_tx_relay->setInventoryTxToSend.clear();
                 }
             }
 
             // Respond to BIP35 mempool requests
             if (fSendTrickle && pto->m_tx_relay->fSendMempool) {
                 auto vtxinfo = g_mempool.infoAll();
                 pto->m_tx_relay->fSendMempool = false;
                 CFeeRate filterrate;
                 {
                     LOCK(pto->m_tx_relay->cs_feeFilter);
                     filterrate = CFeeRate(pto->m_tx_relay->minFeeFilter);
                 }
 
                 LOCK(pto->m_tx_relay->cs_filter);
 
                 for (const auto &txinfo : vtxinfo) {
                     const TxId &txid = txinfo.tx->GetId();
                     CInv inv(MSG_TX, txid);
                     pto->m_tx_relay->setInventoryTxToSend.erase(txid);
                     // Don't send transactions that peers will not put into
                     // their mempool
                     if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) {
                         continue;
                     }
                     if (pto->m_tx_relay->pfilter &&
                         !pto->m_tx_relay->pfilter->IsRelevantAndUpdate(
                             *txinfo.tx)) {
                         continue;
                     }
                     pto->m_tx_relay->filterInventoryKnown.insert(txid);
                     vInv.push_back(inv);
                     if (vInv.size() == MAX_INV_SZ) {
                         connman->PushMessage(
                             pto, msgMaker.Make(NetMsgType::INV, vInv));
                         vInv.clear();
                     }
                 }
                 pto->m_tx_relay->m_last_mempool_req =
                     GetTime<std::chrono::seconds>();
             }
 
             // Determine transactions to relay
             if (fSendTrickle) {
                 // Produce a vector with all candidates for sending
                 std::vector<std::set<TxId>::iterator> vInvTx;
                 vInvTx.reserve(pto->m_tx_relay->setInventoryTxToSend.size());
                 for (std::set<TxId>::iterator it =
                          pto->m_tx_relay->setInventoryTxToSend.begin();
                      it != pto->m_tx_relay->setInventoryTxToSend.end(); it++) {
                     vInvTx.push_back(it);
                 }
                 CFeeRate filterrate;
                 {
                     LOCK(pto->m_tx_relay->cs_feeFilter);
                     filterrate = CFeeRate(pto->m_tx_relay->minFeeFilter);
                 }
                 // Topologically and fee-rate sort the inventory we send for
                 // privacy and priority reasons. A heap is used so that not all
                 // items need sorting if only a few are being sent.
                 CompareInvMempoolOrder compareInvMempoolOrder(&g_mempool);
                 std::make_heap(vInvTx.begin(), vInvTx.end(),
                                compareInvMempoolOrder);
                 // No reason to drain out at many times the network's capacity,
                 // especially since we have many peers and some will draw much
                 // shorter delays.
                 unsigned int nRelayedTransactions = 0;
                 LOCK(pto->m_tx_relay->cs_filter);
                 while (!vInvTx.empty() &&
                        nRelayedTransactions < INVENTORY_BROADCAST_MAX_PER_MB *
                                                   config.GetMaxBlockSize() /
                                                   1000000) {
                     // Fetch the top element from the heap
                     std::pop_heap(vInvTx.begin(), vInvTx.end(),
                                   compareInvMempoolOrder);
                     std::set<TxId>::iterator it = vInvTx.back();
                     vInvTx.pop_back();
                     const TxId txid = *it;
                     // Remove it from the to-be-sent set
                     pto->m_tx_relay->setInventoryTxToSend.erase(it);
                     // Check if not in the filter already
                     if (pto->m_tx_relay->filterInventoryKnown.contains(txid)) {
                         continue;
                     }
                     // Not in the mempool anymore? don't bother sending it.
                     auto txinfo = g_mempool.info(txid);
                     if (!txinfo.tx) {
                         continue;
                     }
                     // Peer told you to not send transactions at that feerate?
                     // Don't bother sending it.
                     if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) {
                         continue;
                     }
                     if (pto->m_tx_relay->pfilter &&
                         !pto->m_tx_relay->pfilter->IsRelevantAndUpdate(
                             *txinfo.tx)) {
                         continue;
                     }
                     // Send
                     vInv.push_back(CInv(MSG_TX, txid));
                     nRelayedTransactions++;
                     {
                         // Expire old relay messages
                         while (!vRelayExpiration.empty() &&
                                vRelayExpiration.front().first < nNow) {
                             mapRelay.erase(vRelayExpiration.front().second);
                             vRelayExpiration.pop_front();
                         }
 
                         auto ret = mapRelay.insert(
                             std::make_pair(txid, std::move(txinfo.tx)));
                         if (ret.second) {
                             vRelayExpiration.push_back(
                                 std::make_pair(nNow +
                                                    std::chrono::microseconds{
                                                        RELAY_TX_CACHE_TIME}
                                                        .count(),
                                                ret.first));
                         }
                     }
                     if (vInv.size() == MAX_INV_SZ) {
                         connman->PushMessage(
                             pto, msgMaker.Make(NetMsgType::INV, vInv));
                         vInv.clear();
                     }
                     pto->m_tx_relay->filterInventoryKnown.insert(txid);
                 }
             }
         }
     }
     if (!vInv.empty()) {
         connman->PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
     }
 
     // Detect whether we're stalling
     current_time = GetTime<std::chrono::microseconds>();
     // nNow is the current system time (GetTimeMicros is not mockable) and
     // should be replaced by the mockable current_time eventually
     nNow = GetTimeMicros();
     if (state.nStallingSince &&
         state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) {
         // Stalling only triggers when the block download window cannot move.
         // During normal steady state, the download window should be much larger
         // than the to-be-downloaded set of blocks, so disconnection should only
         // happen during initial block download.
         LogPrintf("Peer=%d is stalling block download, disconnecting\n",
                   pto->GetId());
         pto->fDisconnect = true;
         return true;
     }
     // 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 peers from which
     // we're downloading validated blocks), disconnect due to timeout. We
     // compensate for other peers to prevent killing off peers due to our own
     // downstream link being saturated. We only count validated in-flight blocks
     // so peers can't advertise non-existing block hashes to unreasonably
     // increase our timeout.
     if (state.vBlocksInFlight.size() > 0) {
         QueuedBlock &queuedBlock = state.vBlocksInFlight.front();
         int nOtherPeersWithValidatedDownloads =
             nPeersWithValidatedDownloads -
             (state.nBlocksInFlightValidHeaders > 0);
         if (nNow > state.nDownloadingSince +
                        consensusParams.nPowTargetSpacing *
                            (BLOCK_DOWNLOAD_TIMEOUT_BASE +
                             BLOCK_DOWNLOAD_TIMEOUT_PER_PEER *
                                 nOtherPeersWithValidatedDownloads)) {
             LogPrintf("Timeout downloading block %s from peer=%d, "
                       "disconnecting\n",
                       queuedBlock.hash.ToString(), pto->GetId());
             pto->fDisconnect = true;
             return true;
         }
     }
 
     // Check for headers sync timeouts
     if (state.fSyncStarted &&
         state.nHeadersSyncTimeout < std::numeric_limits<int64_t>::max()) {
         // Detect whether this is a stalling initial-headers-sync peer
         if (pindexBestHeader->GetBlockTime() <=
             GetAdjustedTime() - 24 * 60 * 60) {
             if (nNow > state.nHeadersSyncTimeout && nSyncStarted == 1 &&
                 (nPreferredDownload - state.fPreferredDownload >= 1)) {
                 // Disconnect a (non-whitelisted) peer if it is our only sync
                 // peer, and we have others we could be using instead.
                 // Note: If all our peers are inbound, then we won't disconnect
                 // our sync peer for stalling; we have bigger problems if we
                 // can't get any outbound peers.
                 if (!pto->HasPermission(PF_NOBAN)) {
                     LogPrintf("Timeout downloading headers from peer=%d, "
                               "disconnecting\n",
                               pto->GetId());
                     pto->fDisconnect = true;
                     return true;
                 } else {
                     LogPrintf("Timeout downloading headers from whitelisted "
                               "peer=%d, not disconnecting\n",
                               pto->GetId());
                     // Reset the headers sync state so that we have a chance to
                     // try downloading from a different peer.
                     // Note: this will also result in at least one more
                     // getheaders message to be sent to this peer (eventually).
                     state.fSyncStarted = false;
                     nSyncStarted--;
                     state.nHeadersSyncTimeout = 0;
                 }
             }
         } else {
             // After we've caught up once, reset the timeout so we can't trigger
             // disconnect later.
             state.nHeadersSyncTimeout = std::numeric_limits<int64_t>::max();
         }
     }
 
     // Check that outbound peers have reasonable chains GetTime() is used by
     // this anti-DoS logic so we can test this using mocktime.
     ConsiderEviction(*pto, GetTime());
 
     //
     // Message: getdata (blocks)
     //
     std::vector<CInv> vGetData;
     if (!pto->fClient &&
         ((fFetch && !pto->m_limited_node) ||
          !::ChainstateActive().IsInitialBlockDownload()) &&
         state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
         std::vector<const CBlockIndex *> vToDownload;
         NodeId staller = -1;
         FindNextBlocksToDownload(pto->GetId(),
                                  MAX_BLOCKS_IN_TRANSIT_PER_PEER -
                                      state.nBlocksInFlight,
                                  vToDownload, staller, consensusParams);
         for (const CBlockIndex *pindex : vToDownload) {
             vGetData.push_back(CInv(MSG_BLOCK, pindex->GetBlockHash()));
             MarkBlockAsInFlight(config, pto->GetId(), pindex->GetBlockHash(),
                                 consensusParams, pindex);
             LogPrint(BCLog::NET, "Requesting block %s (%d) peer=%d\n",
                      pindex->GetBlockHash().ToString(), pindex->nHeight,
                      pto->GetId());
         }
         if (state.nBlocksInFlight == 0 && staller != -1) {
             if (State(staller)->nStallingSince == 0) {
                 State(staller)->nStallingSince = nNow;
                 LogPrint(BCLog::NET, "Stall started peer=%d\n", staller);
             }
         }
     }
 
     //
     // Message: getdata (transactions)
     //
 
     // For robustness, expire old requests after a long timeout, so that we can
     // resume downloading transactions from a peer even if they were
     // unresponsive in the past. Eventually we should consider disconnecting
     // peers, but this is conservative.
     if (state.m_tx_download.m_check_expiry_timer <= current_time) {
         for (auto it = state.m_tx_download.m_tx_in_flight.begin();
              it != state.m_tx_download.m_tx_in_flight.end();) {
             if (it->second <= current_time - TX_EXPIRY_INTERVAL) {
                 LogPrint(BCLog::NET, "timeout of inflight tx %s from peer=%d\n",
                          it->first.ToString(), pto->GetId());
                 state.m_tx_download.m_tx_announced.erase(it->first);
                 state.m_tx_download.m_tx_in_flight.erase(it++);
             } else {
                 ++it;
             }
         }
         // On average, we do this check every TX_EXPIRY_INTERVAL. Randomize
         // so that we're not doing this for all peers at the same time.
         state.m_tx_download.m_check_expiry_timer =
             current_time + TX_EXPIRY_INTERVAL / 2 +
             GetRandMicros(TX_EXPIRY_INTERVAL);
     }
 
     auto &tx_process_time = state.m_tx_download.m_tx_process_time;
     while (!tx_process_time.empty() &&
            tx_process_time.begin()->first <= current_time &&
            state.m_tx_download.m_tx_in_flight.size() < MAX_PEER_TX_IN_FLIGHT) {
         const TxId txid = tx_process_time.begin()->second;
         // Erase this entry from tx_process_time (it may be added back for
         // processing at a later time, see below)
         tx_process_time.erase(tx_process_time.begin());
         CInv inv(MSG_TX, txid);
         if (!AlreadyHave(inv)) {
             // If this transaction was last requested more than 1 minute ago,
             // then request.
             const auto last_request_time = GetTxRequestTime(txid);
             if (last_request_time <= current_time - GETDATA_TX_INTERVAL) {
                 LogPrint(BCLog::NET, "Requesting %s peer=%d\n", inv.ToString(),
                          pto->GetId());
                 vGetData.push_back(inv);
                 if (vGetData.size() >= MAX_GETDATA_SZ) {
                     connman->PushMessage(
                         pto, msgMaker.Make(NetMsgType::GETDATA, vGetData));
                     vGetData.clear();
                 }
                 UpdateTxRequestTime(txid, current_time);
                 state.m_tx_download.m_tx_in_flight.emplace(txid, current_time);
             } else {
                 // This transaction is in flight from someone else; queue
                 // up processing to happen after the download times out
                 // (with a slight delay for inbound peers, to prefer
                 // requests to outbound peers).
                 const auto next_process_time = CalculateTxGetDataTime(
                     txid, current_time, !state.fPreferredDownload);
                 tx_process_time.emplace(next_process_time, txid);
             }
         } else {
             // We have already seen this transaction, no need to download.
             state.m_tx_download.m_tx_announced.erase(txid);
             state.m_tx_download.m_tx_in_flight.erase(txid);
         }
     }
 
     if (!vGetData.empty()) {
         connman->PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData));
     }
 
     //
     // Message: feefilter
     //
     // We don't want white listed peers to filter txs to us if we have
     // -whitelistforcerelay
     if (pto->m_tx_relay != nullptr && pto->nVersion >= FEEFILTER_VERSION &&
         gArgs.GetBoolArg("-feefilter", DEFAULT_FEEFILTER) &&
         !pto->HasPermission(PF_FORCERELAY)) {
         Amount currentFilter =
             g_mempool
                 .GetMinFee(
                     gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) *
                     1000000)
                 .GetFeePerK();
         int64_t timeNow = GetTimeMicros();
         if (timeNow > pto->m_tx_relay->nextSendTimeFeeFilter) {
             static CFeeRate default_feerate =
                 CFeeRate(DEFAULT_MIN_RELAY_TX_FEE_PER_KB);
             static FeeFilterRounder filterRounder(default_feerate);
             Amount filterToSend = filterRounder.round(currentFilter);
             filterToSend = std::max(filterToSend, ::minRelayTxFee.GetFeePerK());
 
             if (filterToSend != pto->m_tx_relay->lastSentFeeFilter) {
                 connman->PushMessage(
                     pto, msgMaker.Make(NetMsgType::FEEFILTER, filterToSend));
                 pto->m_tx_relay->lastSentFeeFilter = filterToSend;
             }
             pto->m_tx_relay->nextSendTimeFeeFilter =
                 PoissonNextSend(timeNow, AVG_FEEFILTER_BROADCAST_INTERVAL);
         }
         // If the fee filter has changed substantially and it's still more than
         // MAX_FEEFILTER_CHANGE_DELAY until scheduled broadcast, then move the
         // broadcast to within MAX_FEEFILTER_CHANGE_DELAY.
         else if (timeNow + MAX_FEEFILTER_CHANGE_DELAY * 1000000 <
                      pto->m_tx_relay->nextSendTimeFeeFilter &&
                  (currentFilter < 3 * pto->m_tx_relay->lastSentFeeFilter / 4 ||
                   currentFilter > 4 * pto->m_tx_relay->lastSentFeeFilter / 3)) {
             pto->m_tx_relay->nextSendTimeFeeFilter =
                 timeNow + GetRandInt(MAX_FEEFILTER_CHANGE_DELAY) * 1000000;
         }
     }
     return true;
 }
 
 class CNetProcessingCleanup {
 public:
     CNetProcessingCleanup() {}
     ~CNetProcessingCleanup() {
         // orphan transactions
         mapOrphanTransactions.clear();
         mapOrphanTransactionsByPrev.clear();
     }
 };
 static CNetProcessingCleanup instance_of_cnetprocessingcleanup;
diff --git a/src/pubkey.cpp b/src/pubkey.cpp
index 609e3d1c6..b3a0949bd 100644
--- a/src/pubkey.cpp
+++ b/src/pubkey.cpp
@@ -1,366 +1,374 @@
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017 The Zcash developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <pubkey.h>
 
 #include <secp256k1.h>
 #include <secp256k1_recovery.h>
 #include <secp256k1_schnorr.h>
 
 namespace {
 /* Global secp256k1_context object used for verification. */
 secp256k1_context *secp256k1_context_verify = nullptr;
 } // namespace
 
 /**
  * This function is taken from the libsecp256k1 distribution and implements DER
  * parsing for ECDSA signatures, while supporting an arbitrary subset of format
  * violations.
  *
  * Supported violations include negative integers, excessive padding, garbage at
  * the end, and overly long length descriptors. This is safe to use in Bitcoin
  * because since the activation of BIP66, signatures are verified to be strict
  * DER before being passed to this module, and we know it supports all
  * violations present in the blockchain before that point.
  */
 static int ecdsa_signature_parse_der_lax(const secp256k1_context *ctx,
                                          secp256k1_ecdsa_signature *sig,
                                          const uint8_t *input,
                                          size_t inputlen) {
     size_t rpos, rlen, spos, slen;
     size_t pos = 0;
     size_t lenbyte;
     uint8_t tmpsig[64] = {0};
     int overflow = 0;
 
     /* Hack to initialize sig with a correctly-parsed but invalid signature. */
     secp256k1_ecdsa_signature_parse_compact(ctx, sig, tmpsig);
 
     /* Sequence tag byte */
     if (pos == inputlen || input[pos] != 0x30) {
         return 0;
     }
     pos++;
 
     /* Sequence length bytes */
     if (pos == inputlen) {
         return 0;
     }
     lenbyte = input[pos++];
     if (lenbyte & 0x80) {
         lenbyte -= 0x80;
         if (lenbyte > inputlen - pos) {
             return 0;
         }
         pos += lenbyte;
     }
 
     /* Integer tag byte for R */
     if (pos == inputlen || input[pos] != 0x02) {
         return 0;
     }
     pos++;
 
     /* Integer length for R */
     if (pos == inputlen) {
         return 0;
     }
     lenbyte = input[pos++];
     if (lenbyte & 0x80) {
         lenbyte -= 0x80;
         if (lenbyte > inputlen - pos) {
             return 0;
         }
         while (lenbyte > 0 && input[pos] == 0) {
             pos++;
             lenbyte--;
         }
         static_assert(sizeof(size_t) >= 4, "size_t too small");
         if (lenbyte >= 4) {
             return 0;
         }
         rlen = 0;
         while (lenbyte > 0) {
             rlen = (rlen << 8) + input[pos];
             pos++;
             lenbyte--;
         }
     } else {
         rlen = lenbyte;
     }
     if (rlen > inputlen - pos) {
         return 0;
     }
     rpos = pos;
     pos += rlen;
 
     /* Integer tag byte for S */
     if (pos == inputlen || input[pos] != 0x02) {
         return 0;
     }
     pos++;
 
     /* Integer length for S */
     if (pos == inputlen) {
         return 0;
     }
     lenbyte = input[pos++];
     if (lenbyte & 0x80) {
         lenbyte -= 0x80;
         if (lenbyte > inputlen - pos) {
             return 0;
         }
         while (lenbyte > 0 && input[pos] == 0) {
             pos++;
             lenbyte--;
         }
         static_assert(sizeof(size_t) >= 4, "size_t too small");
         if (lenbyte >= 4) {
             return 0;
         }
         slen = 0;
         while (lenbyte > 0) {
             slen = (slen << 8) + input[pos];
             pos++;
             lenbyte--;
         }
     } else {
         slen = lenbyte;
     }
     if (slen > inputlen - pos) {
         return 0;
     }
     spos = pos;
 
     /* Ignore leading zeroes in R */
     while (rlen > 0 && input[rpos] == 0) {
         rlen--;
         rpos++;
     }
     /* Copy R value */
     if (rlen > 32) {
         overflow = 1;
     } else {
         memcpy(tmpsig + 32 - rlen, input + rpos, rlen);
     }
 
     /* Ignore leading zeroes in S */
     while (slen > 0 && input[spos] == 0) {
         slen--;
         spos++;
     }
     /* Copy S value */
     if (slen > 32) {
         overflow = 1;
     } else {
         memcpy(tmpsig + 64 - slen, input + spos, slen);
     }
 
     if (!overflow) {
         overflow = !secp256k1_ecdsa_signature_parse_compact(ctx, sig, tmpsig);
     }
     if (overflow) {
         /* Overwrite the result again with a correctly-parsed but invalid
            signature if parsing failed. */
         memset(tmpsig, 0, 64);
         secp256k1_ecdsa_signature_parse_compact(ctx, sig, tmpsig);
     }
     return 1;
 }
 
 bool CPubKey::VerifyECDSA(const uint256 &hash,
                           const std::vector<uint8_t> &vchSig) const {
     if (!IsValid()) {
         return false;
     }
 
     secp256k1_pubkey pubkey;
     secp256k1_ecdsa_signature sig;
     assert(secp256k1_context_verify &&
            "secp256k1_context_verify must be initialized to use CPubKey.");
     if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, vch,
                                    size())) {
         return false;
     }
     if (!ecdsa_signature_parse_der_lax(secp256k1_context_verify, &sig,
                                        vchSig.data(), vchSig.size())) {
         return false;
     }
     /**
      * libsecp256k1's ECDSA verification requires lower-S signatures, which have
      * not historically been enforced in Bitcoin, so normalize them first.
      */
     secp256k1_ecdsa_signature_normalize(secp256k1_context_verify, &sig, &sig);
     return secp256k1_ecdsa_verify(secp256k1_context_verify, &sig, hash.begin(),
                                   &pubkey);
 }
 
-bool CPubKey::VerifySchnorr(const uint256 &hash,
-                            const std::vector<uint8_t> &vchSig) const {
+bool CPubKey::VerifySchnorr(
+    const uint256 &hash, const std::array<uint8_t, SCHNORR_SIZE> &sig) const {
     if (!IsValid()) {
         return false;
     }
 
-    if (vchSig.size() != 64) {
-        return false;
-    }
-
     secp256k1_pubkey pubkey;
     if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey,
                                    &(*this)[0], size())) {
         return false;
     }
 
-    return secp256k1_schnorr_verify(secp256k1_context_verify, vchSig.data(),
+    return secp256k1_schnorr_verify(secp256k1_context_verify, sig.data(),
                                     hash.begin(), &pubkey);
 }
 
+bool CPubKey::VerifySchnorr(const uint256 &hash,
+                            const std::vector<uint8_t> &vchSig) const {
+    if (vchSig.size() != SCHNORR_SIZE) {
+        return false;
+    }
+
+    std::array<uint8_t, SCHNORR_SIZE> sig;
+    std::copy(vchSig.begin(), vchSig.end(), sig.begin());
+
+    return VerifySchnorr(hash, sig);
+}
+
 bool CPubKey::RecoverCompact(const uint256 &hash,
                              const std::vector<uint8_t> &vchSig) {
     if (vchSig.size() != COMPACT_SIGNATURE_SIZE) {
         return false;
     }
 
     int recid = (vchSig[0] - 27) & 3;
     bool fComp = ((vchSig[0] - 27) & 4) != 0;
     secp256k1_pubkey pubkey;
     secp256k1_ecdsa_recoverable_signature sig;
     assert(secp256k1_context_verify &&
            "secp256k1_context_verify must be initialized to use CPubKey.");
     if (!secp256k1_ecdsa_recoverable_signature_parse_compact(
             secp256k1_context_verify, &sig, &vchSig[1], recid)) {
         return false;
     }
     if (!secp256k1_ecdsa_recover(secp256k1_context_verify, &pubkey, &sig,
                                  hash.begin())) {
         return false;
     }
     uint8_t pub[SIZE];
     size_t publen = SIZE;
     secp256k1_ec_pubkey_serialize(
         secp256k1_context_verify, pub, &publen, &pubkey,
         fComp ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
     Set(pub, pub + publen);
     return true;
 }
 
 bool CPubKey::IsFullyValid() const {
     if (!IsValid()) {
         return false;
     }
     secp256k1_pubkey pubkey;
     assert(secp256k1_context_verify &&
            "secp256k1_context_verify must be initialized to use CPubKey.");
     return secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, vch,
                                      size());
 }
 
 bool CPubKey::Decompress() {
     if (!IsValid()) {
         return false;
     }
     secp256k1_pubkey pubkey;
     assert(secp256k1_context_verify &&
            "secp256k1_context_verify must be initialized to use CPubKey.");
     if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, vch,
                                    size())) {
         return false;
     }
     uint8_t pub[SIZE];
     size_t publen = SIZE;
     secp256k1_ec_pubkey_serialize(secp256k1_context_verify, pub, &publen,
                                   &pubkey, SECP256K1_EC_UNCOMPRESSED);
     Set(pub, pub + publen);
     return true;
 }
 
 bool CPubKey::Derive(CPubKey &pubkeyChild, ChainCode &ccChild,
                      unsigned int nChild, const ChainCode &cc) const {
     assert(IsValid());
     assert((nChild >> 31) == 0);
     assert(size() == COMPRESSED_SIZE);
     uint8_t out[64];
     BIP32Hash(cc, nChild, *begin(), begin() + 1, out);
     memcpy(ccChild.begin(), out + 32, 32);
     secp256k1_pubkey pubkey;
     assert(secp256k1_context_verify &&
            "secp256k1_context_verify must be initialized to use CPubKey.");
     if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, vch,
                                    size())) {
         return false;
     }
     if (!secp256k1_ec_pubkey_tweak_add(secp256k1_context_verify, &pubkey,
                                        out)) {
         return false;
     }
     uint8_t pub[COMPRESSED_SIZE];
     size_t publen = COMPRESSED_SIZE;
     secp256k1_ec_pubkey_serialize(secp256k1_context_verify, pub, &publen,
                                   &pubkey, SECP256K1_EC_COMPRESSED);
     pubkeyChild.Set(pub, pub + publen);
     return true;
 }
 
 void CExtPubKey::Encode(uint8_t code[BIP32_EXTKEY_SIZE]) const {
     code[0] = nDepth;
     memcpy(code + 1, vchFingerprint, 4);
     code[5] = (nChild >> 24) & 0xFF;
     code[6] = (nChild >> 16) & 0xFF;
     code[7] = (nChild >> 8) & 0xFF;
     code[8] = (nChild >> 0) & 0xFF;
     memcpy(code + 9, chaincode.begin(), 32);
     assert(pubkey.size() == CPubKey::COMPRESSED_SIZE);
     memcpy(code + 41, pubkey.begin(), CPubKey::COMPRESSED_SIZE);
 }
 
 void CExtPubKey::Decode(const uint8_t code[BIP32_EXTKEY_SIZE]) {
     nDepth = code[0];
     memcpy(vchFingerprint, code + 1, 4);
     nChild = (code[5] << 24) | (code[6] << 16) | (code[7] << 8) | code[8];
     memcpy(chaincode.begin(), code + 9, 32);
     pubkey.Set(code + 41, code + BIP32_EXTKEY_SIZE);
 }
 
 bool CExtPubKey::Derive(CExtPubKey &out, unsigned int _nChild) const {
     out.nDepth = nDepth + 1;
     CKeyID id = pubkey.GetID();
     memcpy(&out.vchFingerprint[0], &id, 4);
     out.nChild = _nChild;
     return pubkey.Derive(out.pubkey, out.chaincode, _nChild, chaincode);
 }
 
 bool CPubKey::CheckLowS(
     const boost::sliced_range<const std::vector<uint8_t>> &vchSig) {
     secp256k1_ecdsa_signature sig;
     assert(secp256k1_context_verify &&
            "secp256k1_context_verify must be initialized to use CPubKey.");
     if (!ecdsa_signature_parse_der_lax(secp256k1_context_verify, &sig,
                                        &vchSig.front(), vchSig.size())) {
         return false;
     }
     return (!secp256k1_ecdsa_signature_normalize(secp256k1_context_verify,
                                                  nullptr, &sig));
 }
 
 /* static */ int ECCVerifyHandle::refcount = 0;
 
 ECCVerifyHandle::ECCVerifyHandle() {
     if (refcount == 0) {
         assert(secp256k1_context_verify == nullptr);
         secp256k1_context_verify =
             secp256k1_context_create(SECP256K1_CONTEXT_VERIFY);
         assert(secp256k1_context_verify != nullptr);
     }
     refcount++;
 }
 
 ECCVerifyHandle::~ECCVerifyHandle() {
     refcount--;
     if (refcount == 0) {
         assert(secp256k1_context_verify != nullptr);
         secp256k1_context_destroy(secp256k1_context_verify);
         secp256k1_context_verify = nullptr;
     }
 }
diff --git a/src/pubkey.h b/src/pubkey.h
index 588a1e906..6cb50030e 100644
--- a/src/pubkey.h
+++ b/src/pubkey.h
@@ -1,228 +1,231 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017 The Zcash developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_PUBKEY_H
 #define BITCOIN_PUBKEY_H
 
 #include <hash.h>
 #include <serialize.h>
 #include <uint256.h>
 
 #include <boost/range/adaptor/sliced.hpp>
 
 #include <stdexcept>
 #include <vector>
 
 const unsigned int BIP32_EXTKEY_SIZE = 74;
 
 /** A reference to a CKey: the Hash160 of its serialized public key */
 class CKeyID : public uint160 {
 public:
     CKeyID() : uint160() {}
     explicit CKeyID(const uint160 &in) : uint160(in) {}
 };
 
-typedef uint256 ChainCode;
+using ChainCode = uint256;
 
 /** An encapsulated public key. */
 class CPubKey {
 public:
     /**
      * secp256k1:
      */
     static constexpr unsigned int SIZE = 65;
     static constexpr unsigned int COMPRESSED_SIZE = 33;
+    static constexpr unsigned int SCHNORR_SIZE = 64;
     static constexpr unsigned int SIGNATURE_SIZE = 72;
     static constexpr unsigned int COMPACT_SIGNATURE_SIZE = 65;
     /**
      * see www.keylength.com
      * script supports up to 75 for single byte push
      */
     static_assert(SIZE >= COMPRESSED_SIZE,
                   "COMPRESSED_SIZE is larger than SIZE");
 
 private:
     /**
      * Just store the serialized data.
      * Its length can very cheaply be computed from the first byte.
      */
     uint8_t vch[SIZE];
 
     //! Compute the length of a pubkey with a given first byte.
     static unsigned int GetLen(uint8_t chHeader) {
         if (chHeader == 2 || chHeader == 3) {
             return COMPRESSED_SIZE;
         }
         if (chHeader == 4 || chHeader == 6 || chHeader == 7) {
             return SIZE;
         }
         return 0;
     }
 
     //! Set this key data to be invalid
     void Invalidate() { vch[0] = 0xFF; }
 
 public:
     bool static ValidSize(const std::vector<uint8_t> &vch) {
         return vch.size() > 0 && GetLen(vch[0]) == vch.size();
     }
 
     //! Construct an invalid public key.
     CPubKey() { Invalidate(); }
 
     //! Initialize a public key using begin/end iterators to byte data.
     template <typename T> void Set(const T pbegin, const T pend) {
         int len = pend == pbegin ? 0 : GetLen(pbegin[0]);
         if (len && len == (pend - pbegin)) {
             memcpy(vch, (uint8_t *)&pbegin[0], len);
         } else {
             Invalidate();
         }
     }
 
     //! Construct a public key using begin/end iterators to byte data.
     template <typename T> CPubKey(const T pbegin, const T pend) {
         Set(pbegin, pend);
     }
 
     //! Construct a public key from a byte vector.
     explicit CPubKey(const std::vector<uint8_t> &_vch) {
         Set(_vch.begin(), _vch.end());
     }
 
     //! Simple read-only vector-like interface to the pubkey data.
     unsigned int size() const { return GetLen(vch[0]); }
     const uint8_t *data() const { return vch; }
     const uint8_t *begin() const { return vch; }
     const uint8_t *end() const { return vch + size(); }
     const uint8_t &operator[](unsigned int pos) const { return vch[pos]; }
 
     //! Comparator implementation.
     friend bool operator==(const CPubKey &a, const CPubKey &b) {
         return a.vch[0] == b.vch[0] && memcmp(a.vch, b.vch, a.size()) == 0;
     }
     friend bool operator!=(const CPubKey &a, const CPubKey &b) {
         return !(a == b);
     }
     friend bool operator<(const CPubKey &a, const CPubKey &b) {
         return a.vch[0] < b.vch[0] ||
                (a.vch[0] == b.vch[0] && memcmp(a.vch, b.vch, a.size()) < 0);
     }
 
     //! Implement serialization, as if this was a byte vector.
     template <typename Stream> void Serialize(Stream &s) const {
         unsigned int len = size();
         ::WriteCompactSize(s, len);
         s.write((char *)vch, len);
     }
     template <typename Stream> void Unserialize(Stream &s) {
         unsigned int len = ::ReadCompactSize(s);
         if (len <= SIZE) {
             s.read((char *)vch, len);
         } else {
             // invalid pubkey, skip available data
             char dummy;
             while (len--) {
                 s.read(&dummy, 1);
             }
             Invalidate();
         }
     }
 
     //! Get the KeyID of this public key (hash of its serialization)
     CKeyID GetID() const { return CKeyID(Hash160(vch, vch + size())); }
 
     //! Get the 256-bit hash of this public key.
     uint256 GetHash() const { return Hash(vch, vch + size()); }
 
     /*
      * Check syntactic correctness.
      *
      * Note that this is consensus critical as CheckSig() calls it!
      */
     bool IsValid() const { return size() > 0; }
 
     //! fully validate whether this is a valid public key (more expensive than
     //! IsValid())
     bool IsFullyValid() const;
 
     //! Check whether this is a compressed public key.
     bool IsCompressed() const { return size() == COMPRESSED_SIZE; }
 
     /**
      * Verify a DER-serialized ECDSA signature (~72 bytes).
      * If this public key is not fully valid, the return value will be false.
      */
     bool VerifyECDSA(const uint256 &hash,
                      const std::vector<uint8_t> &vchSig) const;
 
     /**
      * Verify a Schnorr signature (=64 bytes).
      * If this public key is not fully valid, the return value will be false.
      */
+    bool VerifySchnorr(const uint256 &hash,
+                       const std::array<uint8_t, SCHNORR_SIZE> &sig) const;
     bool VerifySchnorr(const uint256 &hash,
                        const std::vector<uint8_t> &vchSig) const;
 
     /**
      * Check whether a DER-serialized ECDSA signature is normalized (lower-S).
      */
     static bool
     CheckLowS(const boost::sliced_range<const std::vector<uint8_t>> &vchSig);
     static bool CheckLowS(const std::vector<uint8_t> &vchSig) {
         return CheckLowS(vchSig | boost::adaptors::sliced(0, vchSig.size()));
     }
 
     //! Recover a public key from a compact ECDSA signature.
     bool RecoverCompact(const uint256 &hash,
                         const std::vector<uint8_t> &vchSig);
 
     //! Turn this public key into an uncompressed public key.
     bool Decompress();
 
     //! Derive BIP32 child pubkey.
     bool Derive(CPubKey &pubkeyChild, ChainCode &ccChild, unsigned int nChild,
                 const ChainCode &cc) const;
 };
 
 struct CExtPubKey {
     uint8_t nDepth;
     uint8_t vchFingerprint[4];
     unsigned int nChild;
     ChainCode chaincode;
     CPubKey pubkey;
 
     friend bool operator==(const CExtPubKey &a, const CExtPubKey &b) {
         return a.nDepth == b.nDepth &&
                memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0],
                       sizeof(vchFingerprint)) == 0 &&
                a.nChild == b.nChild && a.chaincode == b.chaincode &&
                a.pubkey == b.pubkey;
     }
 
     friend bool operator!=(const CExtPubKey &a, const CExtPubKey &b) {
         return !(a == b);
     }
 
     void Encode(uint8_t code[BIP32_EXTKEY_SIZE]) const;
     void Decode(const uint8_t code[BIP32_EXTKEY_SIZE]);
     bool Derive(CExtPubKey &out, unsigned int nChild) const;
 
     CExtPubKey() = default;
 };
 
 /**
  * Users of this module must hold an ECCVerifyHandle. The constructor and
  * destructor of these are not allowed to run in parallel, though.
  */
 class ECCVerifyHandle {
     static int refcount;
 
 public:
     ECCVerifyHandle();
     ~ECCVerifyHandle();
 };
 
 #endif // BITCOIN_PUBKEY_H