Give V1TransportDeserializer CChainParams& member

This adds a CChainParams& member to V1TransportDeserializer member, and
use it in place of many Params() calls.  In addition to reducing the
number of calls to a global, this removes a parameter from GetMessage
(and will later allow us to remove one from CMessageHeader::IsValid())

src/net.cpp

@@ -10,7 +10,6 @@
 #include <net.h>
 
 #include <banman.h>
-#include <chainparams.h>
 #include <clientversion.h>
 #include <consensus/consensus.h>
 #include <crypto/sha256.h>
@@ -615,7 +614,7 @@ bool CNode::ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete
         if (m_deserializer->Complete()) {
             // decompose a transport agnostic CNetMessage from the deserializer
             uint32_t out_err_raw_size{0};
-            Optional<CNetMessage> result{m_deserializer->GetMessage(Params().MessageStart(), time, out_err_raw_size)};
+            Optional<CNetMessage> result{m_deserializer->GetMessage(time, out_err_raw_size)};
             if (!result) {
                 // store the size of the corrupt message
                 mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER)->second += out_err_raw_size;
@@ -697,22 +696,23 @@ const uint256& V1TransportDeserializer::GetMessageHash() const
     return data_hash;
 }
 
-Optional<CNetMessage> V1TransportDeserializer::GetMessage(const CMessageHeader::MessageStartChars& message_start, const std::chrono::microseconds time, uint32_t& out_err_raw_size)
+Optional<CNetMessage> V1TransportDeserializer::GetMessage(const std::chrono::microseconds time, uint32_t& out_err_raw_size)
 {
     // decompose a single CNetMessage from the TransportDeserializer
     Optional<CNetMessage> msg(std::move(vRecv));
 
     // store state about valid header, netmagic and checksum
-    msg->m_valid_header = hdr.IsValid(message_start);
-    msg->m_valid_netmagic = (memcmp(hdr.pchMessageStart, message_start, CMessageHeader::MESSAGE_START_SIZE) == 0);
-    uint256 hash = GetMessageHash();
+    msg->m_valid_header = hdr.IsValid(m_chain_params.MessageStart());
+    msg->m_valid_netmagic = (memcmp(hdr.pchMessageStart, m_chain_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) == 0);
 
     // store command string, time, and sizes
     msg->m_command = hdr.GetCommand();
     msg->m_time = time;
     msg->m_message_size = hdr.nMessageSize;
     msg->m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
 
+    uint256 hash = GetMessageHash();
+
     // We just received a message off the wire, harvest entropy from the time (and the message checksum)
     RandAddEvent(ReadLE32(hash.begin()));
 
@@ -2846,7 +2846,7 @@ CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn
         LogPrint(BCLog::NET, "Added connection peer=%d\n", id);
     }
 
-    m_deserializer = MakeUnique<V1TransportDeserializer>(V1TransportDeserializer(GetId(), SER_NETWORK, INIT_PROTO_VERSION));
+    m_deserializer = MakeUnique<V1TransportDeserializer>(V1TransportDeserializer(Params(), GetId(), SER_NETWORK, INIT_PROTO_VERSION));
     m_serializer = MakeUnique<V1TransportSerializer>(V1TransportSerializer());
 }
 

src/net.h

@@ -10,6 +10,7 @@
 #include <addrman.h>
 #include <amount.h>
 #include <bloom.h>
+#include <chainparams.h>
 #include <compat.h>
 #include <crypto/siphash.h>
 #include <hash.h>
@@ -732,13 +733,14 @@ class TransportDeserializer {
     // read and deserialize data
     virtual int Read(const char *data, unsigned int bytes) = 0;
     // decomposes a message from the context
-    virtual Optional<CNetMessage> GetMessage(const CMessageHeader::MessageStartChars& message_start, std::chrono::microseconds time, uint32_t& out_err) = 0;
+    virtual Optional<CNetMessage> GetMessage(std::chrono::microseconds time, uint32_t& out_err) = 0;
     virtual ~TransportDeserializer() {}
 };
 
 class V1TransportDeserializer final : public TransportDeserializer
 {
 private:
+    const CChainParams& m_chain_params;
     const NodeId m_node_id; // Only for logging
     mutable CHash256 hasher;
     mutable uint256 data_hash;
@@ -765,8 +767,9 @@ class V1TransportDeserializer final : public TransportDeserializer
     }
 
 public:
-    V1TransportDeserializer(const NodeId node_id, int nTypeIn, int nVersionIn)
-        : m_node_id(node_id),
+    V1TransportDeserializer(const CChainParams& chain_params, const NodeId node_id, int nTypeIn, int nVersionIn)
+        : m_chain_params(chain_params),
+          m_node_id(node_id),
           hdrbuf(nTypeIn, nVersionIn),
           vRecv(nTypeIn, nVersionIn)
     {
@@ -789,7 +792,7 @@ class V1TransportDeserializer final : public TransportDeserializer
         if (ret < 0) Reset();
         return ret;
     }
-    Optional<CNetMessage> GetMessage(const CMessageHeader::MessageStartChars& message_start, std::chrono::microseconds time, uint32_t& out_err_raw_size) override;
+    Optional<CNetMessage> GetMessage(std::chrono::microseconds time, uint32_t& out_err_raw_size) override;
 };
 
 /** The TransportSerializer prepares messages for the network transport

src/test/fuzz/p2p_transport_deserializer.cpp

@@ -20,7 +20,7 @@ void initialize()
 void test_one_input(const std::vector<uint8_t>& buffer)
 {
     // Construct deserializer, with a dummy NodeId
-    V1TransportDeserializer deserializer{(NodeId)0, SER_NETWORK, INIT_PROTO_VERSION};
+    V1TransportDeserializer deserializer{Params(), (NodeId)0, SER_NETWORK, INIT_PROTO_VERSION};
     const char* pch = (const char*)buffer.data();
     size_t n_bytes = buffer.size();
     while (n_bytes > 0) {
@@ -33,7 +33,7 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         if (deserializer.Complete()) {
             const std::chrono::microseconds m_time{std::numeric_limits<int64_t>::max()};
             uint32_t out_err_raw_size{0};
-            Optional<CNetMessage> result{deserializer.GetMessage(Params().MessageStart(), m_time, out_err_raw_size)};
+            Optional<CNetMessage> result{deserializer.GetMessage(m_time, out_err_raw_size)};
             if (result) {
                 assert(result->m_command.size() <= CMessageHeader::COMMAND_SIZE);
                 assert(result->m_raw_message_size <= buffer.size());