Merge bitcoin/bitcoin#27324: net: #27257 follow-ups

cd0c8eeb0940790b6ba83786d1c9e362d4dc4829 [net] Pass nRecvFloodSize to CNode (dergoegge)
860402ef2ed728ef096dda4e65e77d566782209f [net] Remove trivial GetConnectionType() getter (dergoegge)
b5a85b365a4abd98176b0935015dbb502cc3e6f6 [net] Delete CNetMessage copy constructor/assignment op (dergoegge)

Pull request description:

  Follow-up PR for #27257

  * Deletes the copy constructor/assignment operator of `CNetMessage`
  * Removes trivial getter for the connection type
  * Avoids passing `nRecvFloodSize` to CNode methods by passing it to `CNode` on creation

ACKs for top commit:
  jnewbery:
    utACK cd0c8eeb0940790b6ba83786d1c9e362d4dc4829
  theStack:
    ACK cd0c8eeb0940790b6ba83786d1c9e362d4dc4829

Tree-SHA512: 673a758668617f69fba77e61f0eaa1538da27a4849c82c98742436692baa2d7f001129af3e7a66b160e599d12109dac08137a146f10ff9b9ebdc5c2237311d41

5 files changed, 32 insertions, 26 deletions

diff --git a/src/net.cpp b/src/net.cpp
index 59a84f2fdf..7023cb0f49 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -573,7 +573,10 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
                              pszDest ? pszDest : "",
                              conn_type,
                              /*inbound_onion=*/false,
-                             CNodeOptions{ .i2p_sam_session = std::move(i2p_transient_session) });
+                             CNodeOptions{
+                                 .i2p_sam_session = std::move(i2p_transient_session),
+                                 .recv_flood_size = nReceiveFloodSize,
+                             });
     pnode->AddRef();
 
     // We're making a new connection, harvest entropy from the time (and our peer count)
@@ -917,7 +920,7 @@ bool CConnman::AttemptToEvictConnection()
                 .m_is_local = node->addr.IsLocal(),
                 .m_network = node->ConnectedThroughNetwork(),
                 .m_noban = node->HasPermission(NetPermissionFlags::NoBan),
-                .m_conn_type = node->GetConnectionType(),
+                .m_conn_type = node->m_conn_type,
             };
             vEvictionCandidates.push_back(candidate);
         }
@@ -1051,8 +1054,9 @@ void CConnman::CreateNodeFromAcceptedSocket(std::unique_ptr<Sock>&& sock,
                              ConnectionType::INBOUND,
                              inbound_onion,
                              CNodeOptions{
-                               .permission_flags = permission_flags,
-                               .prefer_evict = discouraged,
+                                 .permission_flags = permission_flags,
+                                 .prefer_evict = discouraged,
+                                 .recv_flood_size = nReceiveFloodSize,
                              });
     pnode->AddRef();
     m_msgproc->InitializeNode(*pnode, nodeServices);
@@ -1092,7 +1096,7 @@ bool CConnman::AddConnection(const std::string& address, ConnectionType conn_typ
 
     // Count existing connections
     int existing_connections = WITH_LOCK(m_nodes_mutex,
-                                         return std::count_if(m_nodes.begin(), m_nodes.end(), [conn_type](CNode* node) { return node->GetConnectionType() == conn_type; }););
+                                         return std::count_if(m_nodes.begin(), m_nodes.end(), [conn_type](CNode* node) { return node->m_conn_type == conn_type; }););
 
     // Max connections of specified type already exist
     if (max_connections != std::nullopt && existing_connections >= max_connections) return false;
@@ -1328,7 +1332,7 @@ void CConnman::SocketHandlerConnected(const std::vector<CNode*>& nodes,
                 }
                 RecordBytesRecv(nBytes);
                 if (notify) {
-                    pnode->MarkReceivedMsgsForProcessing(nReceiveFloodSize);
+                    pnode->MarkReceivedMsgsForProcessing();
                     WakeMessageHandler();
                 }
             }
@@ -1711,7 +1715,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
                 if (pnode->IsBlockOnlyConn()) nOutboundBlockRelay++;
 
                 // Make sure our persistent outbound slots belong to different netgroups.
-                switch (pnode->GetConnectionType()) {
+                switch (pnode->m_conn_type) {
                     // We currently don't take inbound connections into account. Since they are
                     // free to make, an attacker could make them to prevent us from connecting to
                     // certain peers.
@@ -2754,8 +2758,6 @@ ServiceFlags CConnman::GetLocalServices() const
     return nLocalServices;
 }
 
-unsigned int CConnman::GetReceiveFloodSize() const { return nReceiveFloodSize; }
-
 CNode::CNode(NodeId idIn,
              std::shared_ptr<Sock> sock,
              const CAddress& addrIn,
@@ -2777,9 +2779,10 @@ CNode::CNode(NodeId idIn,
       m_inbound_onion{inbound_onion},
       m_prefer_evict{node_opts.prefer_evict},
       nKeyedNetGroup{nKeyedNetGroupIn},
+      m_conn_type{conn_type_in},
       id{idIn},
       nLocalHostNonce{nLocalHostNonceIn},
-      m_conn_type{conn_type_in},
+      m_recv_flood_size{node_opts.recv_flood_size},
       m_i2p_sam_session{std::move(node_opts.i2p_sam_session)}
 {
     if (inbound_onion) assert(conn_type_in == ConnectionType::INBOUND);
@@ -2795,7 +2798,7 @@ CNode::CNode(NodeId idIn,
     }
 }
 
-void CNode::MarkReceivedMsgsForProcessing(unsigned int recv_flood_size)
+void CNode::MarkReceivedMsgsForProcessing()
 {
     AssertLockNotHeld(m_msg_process_queue_mutex);
 
@@ -2809,10 +2812,10 @@ void CNode::MarkReceivedMsgsForProcessing(unsigned int recv_flood_size)
     LOCK(m_msg_process_queue_mutex);
     m_msg_process_queue.splice(m_msg_process_queue.end(), vRecvMsg);
     m_msg_process_queue_size += nSizeAdded;
-    fPauseRecv = m_msg_process_queue_size > recv_flood_size;
+    fPauseRecv = m_msg_process_queue_size > m_recv_flood_size;
 }
 
-std::optional<std::pair<CNetMessage, bool>> CNode::PollMessage(size_t recv_flood_size)
+std::optional<std::pair<CNetMessage, bool>> CNode::PollMessage()
 {
     LOCK(m_msg_process_queue_mutex);
     if (m_msg_process_queue.empty()) return std::nullopt;
@@ -2821,7 +2824,7 @@ std::optional<std::pair<CNetMessage, bool>> CNode::PollMessage(size_t recv_flood
     // Just take one message
     msgs.splice(msgs.begin(), m_msg_process_queue, m_msg_process_queue.begin());
     m_msg_process_queue_size -= msgs.front().m_raw_message_size;
-    fPauseRecv = m_msg_process_queue_size > recv_flood_size;
+    fPauseRecv = m_msg_process_queue_size > m_recv_flood_size;
 
     return std::make_pair(std::move(msgs.front()), !m_msg_process_queue.empty());
 }
diff --git a/src/net.h b/src/net.h
index 7bb164003e..9b939aea5c 100644
--- a/src/net.h
+++ b/src/net.h
@@ -236,6 +236,14 @@ public:
     std::string m_type;
 
     CNetMessage(CDataStream&& recv_in) : m_recv(std::move(recv_in)) {}
+    // Only one CNetMessage object will exist for the same message on either
+    // the receive or processing queue. For performance reasons we therefore
+    // delete the copy constructor and assignment operator to avoid the
+    // possibility of copying CNetMessage objects.
+    CNetMessage(CNetMessage&&) = default;
+    CNetMessage(const CNetMessage&) = delete;
+    CNetMessage& operator=(CNetMessage&&) = default;
+    CNetMessage& operator=(const CNetMessage&) = delete;
 
     void SetVersion(int nVersionIn)
     {
@@ -342,6 +350,7 @@ struct CNodeOptions
     NetPermissionFlags permission_flags = NetPermissionFlags::None;
     std::unique_ptr<i2p::sam::Session> i2p_sam_session = nullptr;
     bool prefer_evict = false;
+    size_t recv_flood_size{DEFAULT_MAXRECEIVEBUFFER * 1000};
 };
 
 /** Information about a peer */
@@ -410,13 +419,10 @@ public:
     std::atomic_bool fPauseRecv{false};
     std::atomic_bool fPauseSend{false};
 
-    const ConnectionType& GetConnectionType() const
-    {
-        return m_conn_type;
-    }
+    const ConnectionType m_conn_type;
 
     /** Move all messages from the received queue to the processing queue. */
-    void MarkReceivedMsgsForProcessing(unsigned int recv_flood_size)
+    void MarkReceivedMsgsForProcessing()
         EXCLUSIVE_LOCKS_REQUIRED(!m_msg_process_queue_mutex);
 
     /** Poll the next message from the processing queue of this connection.
@@ -424,7 +430,7 @@ public:
      * Returns std::nullopt if the processing queue is empty, or a pair
      * consisting of the message and a bool that indicates if the processing
      * queue has more entries. */
-    std::optional<std::pair<CNetMessage, bool>> PollMessage(size_t recv_flood_size)
+    std::optional<std::pair<CNetMessage, bool>> PollMessage()
         EXCLUSIVE_LOCKS_REQUIRED(!m_msg_process_queue_mutex);
 
     /** Account for the total size of a sent message in the per msg type connection stats. */
@@ -614,9 +620,9 @@ public:
 private:
     const NodeId id;
     const uint64_t nLocalHostNonce;
-    const ConnectionType m_conn_type;
     std::atomic<int> m_greatest_common_version{INIT_PROTO_VERSION};
 
+    const size_t m_recv_flood_size;
     std::list<CNetMessage> vRecvMsg; // Used only by SocketHandler thread
 
     Mutex m_msg_process_queue_mutex;
@@ -879,8 +885,6 @@ public:
     /** Get a unique deterministic randomizer. */
     CSipHasher GetDeterministicRandomizer(uint64_t id) const;
 
-    unsigned int GetReceiveFloodSize() const;
-
     void WakeMessageHandler() EXCLUSIVE_LOCKS_REQUIRED(!mutexMsgProc);
 
     /** Return true if we should disconnect the peer for failing an inactivity check. */
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 3df5374e21..6d65d9ec8b 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -4887,7 +4887,7 @@ bool PeerManagerImpl::ProcessMessages(CNode* pfrom, std::atomic<bool>& interrupt
     // Don't bother if send buffer is too full to respond anyway
     if (pfrom->fPauseSend) return false;
 
-    auto poll_result{pfrom->PollMessage(m_connman.GetReceiveFloodSize())};
+    auto poll_result{pfrom->PollMessage()};
     if (!poll_result) {
         // No message to process
         return false;
diff --git a/src/test/fuzz/connman.cpp b/src/test/fuzz/connman.cpp
index 798c14030c..7ce17c0b7c 100644
--- a/src/test/fuzz/connman.cpp
+++ b/src/test/fuzz/connman.cpp
@@ -125,7 +125,6 @@ FUZZ_TARGET_INIT(connman, initialize_connman)
     std::vector<CNodeStats> stats;
     connman.GetNodeStats(stats);
     (void)connman.GetOutboundTargetBytesLeft();
-    (void)connman.GetReceiveFloodSize();
     (void)connman.GetTotalBytesRecv();
     (void)connman.GetTotalBytesSent();
     (void)connman.GetTryNewOutboundPeer();
diff --git a/src/test/util/net.cpp b/src/test/util/net.cpp
index 27a1277680..3f72384b3b 100644
--- a/src/test/util/net.cpp
+++ b/src/test/util/net.cpp
@@ -66,7 +66,7 @@ void ConnmanTestMsg::NodeReceiveMsgBytes(CNode& node, Span<const uint8_t> msg_by
 {
     assert(node.ReceiveMsgBytes(msg_bytes, complete));
     if (complete) {
-        node.MarkReceivedMsgsForProcessing(nReceiveFloodSize);
+        node.MarkReceivedMsgsForProcessing();
     }
 }