Convert mapBlocksInFlight to a multimap

Github-Pull: #27626
Rebased-From: cce96182ba

src/net_processing.cpp

@@ -900,7 +900,8 @@ private:
      */
     void FindNextBlocksToDownload(const Peer& peer, unsigned int count, std::vector<const CBlockIndex*>& vBlocks, NodeId& nodeStaller) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
-    typedef std::map<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator>> BlockDownloadMap;
+    /* Multimap used to preserve insertion order */
+    typedef std::multimap<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator>> BlockDownloadMap;
     BlockDownloadMap mapBlocksInFlight GUARDED_BY(cs_main);
 
     /** When our tip was last updated. */
@@ -1124,34 +1125,40 @@ bool PeerManagerImpl::IsBlockRequested(const uint256& hash)
 
 void PeerManagerImpl::RemoveBlockRequest(const uint256& hash, std::optional<NodeId> from_peer)
 {
-    auto it = mapBlocksInFlight.find(hash);
+    auto range = mapBlocksInFlight.equal_range(hash);
-    if (it == mapBlocksInFlight.end()) {
+    if (range.first == range.second) {
-        // Block was not requested
+        // Block was not requested from any peer
         return;
     }
 
-    auto [node_id, list_it] = it->second;
+    // Currently we don't request more than one peer for same block
+    Assume(mapBlocksInFlight.count(hash) == 1);
 
-    if (from_peer && node_id != *from_peer) {
+    while (range.first != range.second) {
-        // Block was requested by another peer
+        auto [node_id, list_it] = range.first->second;
-        return;
+
+        if (from_peer && *from_peer != node_id) {
+            range.first++;
+            continue;
+        }
+
+        CNodeState *state = State(node_id);
+        assert(state != nullptr);
+
+        if (state->vBlocksInFlight.begin() == list_it) {
+            // First block on the queue was received, update the start download time for the next one
+            state->m_downloading_since = std::max(state->m_downloading_since, GetTime<std::chrono::microseconds>());
+        }
+        state->vBlocksInFlight.erase(list_it);
+
+        if (state->vBlocksInFlight.empty()) {
+            // Last validated block on the queue for this peer was received.
+            m_peers_downloading_from--;
+        }
+        state->m_stalling_since = 0us;
+
+        range.first = mapBlocksInFlight.erase(range.first);
     }
-
-    CNodeState *state = State(node_id);
-    assert(state != nullptr);
-
-    if (state->vBlocksInFlight.begin() == list_it) {
-        // First block on the queue was received, update the start download time for the next one
-        state->m_downloading_since = std::max(state->m_downloading_since, GetTime<std::chrono::microseconds>());
-    }
-    state->vBlocksInFlight.erase(list_it);
-
-    if (state->vBlocksInFlight.empty()) {
-        // Last validated block on the queue was received.
-        m_peers_downloading_from--;
-    }
-    state->m_stalling_since = 0us;
-    mapBlocksInFlight.erase(it);
 }
 
 bool PeerManagerImpl::BlockRequested(NodeId nodeid, const CBlockIndex& block, std::list<QueuedBlock>::iterator** pit)
@@ -1162,12 +1169,13 @@ bool PeerManagerImpl::BlockRequested(NodeId nodeid, const CBlockIndex& block, st
     assert(state != nullptr);
 
     // Short-circuit most stuff in case it is from the same node
-    BlockDownloadMap::iterator itInFlight = mapBlocksInFlight.find(hash);
+    for (auto range = mapBlocksInFlight.equal_range(hash); range.first != range.second; range.first++) {
-    if (itInFlight != mapBlocksInFlight.end() && itInFlight->second.first == nodeid) {
+        if (range.first->second.first == nodeid) {
-        if (pit) {
+            if (pit) {
-            *pit = &itInFlight->second.second;
+                *pit = &range.first->second.second;
+            }
+            return false;
         }
-        return false;
     }
 
     // Make sure it's not listed somewhere already.
@@ -1180,7 +1188,7 @@ bool PeerManagerImpl::BlockRequested(NodeId nodeid, const CBlockIndex& block, st
         state->m_downloading_since = GetTime<std::chrono::microseconds>();
         m_peers_downloading_from++;
     }
-    itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it))).first;
+    auto itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it)));
     if (pit) {
         *pit = &itInFlight->second.second;
     }
@@ -1383,7 +1391,7 @@ void PeerManagerImpl::FindNextBlocksToDownload(const Peer& peer, unsigned int co
                 }
             } else if (waitingfor == -1) {
                 // This is the first already-in-flight block.
-                waitingfor = mapBlocksInFlight[pindex->GetBlockHash()].first;
+                waitingfor = mapBlocksInFlight.lower_bound(pindex->GetBlockHash())->second.first;
             }
         }
     }
@@ -1513,7 +1521,15 @@ void PeerManagerImpl::FinalizeNode(const CNode& node)
         nSyncStarted--;
 
     for (const QueuedBlock& entry : state->vBlocksInFlight) {
-        mapBlocksInFlight.erase(entry.pindex->GetBlockHash());
+        auto range = mapBlocksInFlight.equal_range(entry.pindex->GetBlockHash());
+        while (range.first != range.second) {
+            auto [node_id, list_it] = range.first->second;
+            if (node_id != nodeid) {
+                range.first++;
+            } else {
+                range.first = mapBlocksInFlight.erase(range.first);
+            }
+        }
     }
     m_orphanage.EraseForPeer(nodeid);
     m_txrequest.DisconnectedPeer(nodeid);
@@ -4271,12 +4287,21 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             nodestate->m_last_block_announcement = GetTime();
         }
 
-        BlockDownloadMap::iterator blockInFlightIt = mapBlocksInFlight.find(pindex->GetBlockHash());
-        bool fAlreadyInFlight = blockInFlightIt != mapBlocksInFlight.end();
-
         if (pindex->nStatus & BLOCK_HAVE_DATA) // Nothing to do here
             return;
 
+        auto range_flight = mapBlocksInFlight.equal_range(pindex->GetBlockHash());
+        bool fAlreadyInFlight = range_flight.first != range_flight.second;
+        bool in_flight_same_peer{false};
+
+        while (range_flight.first != range_flight.second) {
+            if (range_flight.first->second.first == pfrom.GetId()) {
+                in_flight_same_peer = true;
+                break;
+            }
+            range_flight.first++;
+        }
+
         if (pindex->nChainWork <= m_chainman.ActiveChain().Tip()->nChainWork || // We know something better
                 pindex->nTx != 0) { // We had this block at some point, but pruned it
             if (fAlreadyInFlight) {
@@ -4298,7 +4323,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         // possibilities in compact block processing...
         if (pindex->nHeight <= m_chainman.ActiveChain().Height() + 2) {
             if ((!fAlreadyInFlight && nodestate->vBlocksInFlight.size() < MAX_BLOCKS_IN_TRANSIT_PER_PEER) ||
-                 (fAlreadyInFlight && blockInFlightIt->second.first == pfrom.GetId())) {
+                 in_flight_same_peer) {
                 std::list<QueuedBlock>::iterator* queuedBlockIt = nullptr;
                 if (!BlockRequested(pfrom.GetId(), *pindex, &queuedBlockIt)) {
                     if (!(*queuedBlockIt)->partialBlock)
@@ -4430,14 +4455,23 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         {
             LOCK(cs_main);
 
-            BlockDownloadMap::iterator it = mapBlocksInFlight.find(resp.blockhash);
+            bool expected_blocktxn = false;
-            if (it == mapBlocksInFlight.end() || !it->second.second->partialBlock ||
+            auto range_flight = mapBlocksInFlight.equal_range(resp.blockhash);
-                    it->second.first != pfrom.GetId()) {
+            while (range_flight.first != range_flight.second) {
+                auto [node_id, block_it] = range_flight.first->second;
+                if (node_id == pfrom.GetId() && block_it->partialBlock) {
+                    expected_blocktxn = true;
+                    break;
+                }
+                range_flight.first++;
+            }
+
+            if (!expected_blocktxn) {
                 LogPrint(BCLog::NET, "Peer %d sent us block transactions for block we weren't expecting\n", pfrom.GetId());
                 return;
             }
 
-            PartiallyDownloadedBlock& partialBlock = *it->second.second->partialBlock;
+            PartiallyDownloadedBlock& partialBlock = *range_flight.first->second.second->partialBlock;
             ReadStatus status = partialBlock.FillBlock(*pblock, resp.txn);
             if (status == READ_STATUS_INVALID) {
                 RemoveBlockRequest(resp.blockhash, pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect