net: set message deserialization version when it's actually time to deserialize

We'll soon no longer have access to vRecvMsg, and this is more intuitive anyway.

src/net.cpp

@@ -653,7 +653,7 @@ bool CNode::ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete
         // get current incomplete message, or create a new one
         if (vRecvMsg.empty() ||
             vRecvMsg.back().complete())
-            vRecvMsg.push_back(CNetMessage(Params().MessageStart(), SER_NETWORK, nRecvVersion));
+            vRecvMsg.push_back(CNetMessage(Params().MessageStart(), SER_NETWORK, INIT_PROTO_VERSION));
 
         CNetMessage& msg = vRecvMsg.back();
 

src/net.h

@@ -607,7 +607,7 @@ public:
     std::list<CNetMessage> vRecvMsg;
     CCriticalSection cs_vRecvMsg;
     uint64_t nRecvBytes;
-    int nRecvVersion;
+    std::atomic<int> nRecvVersion;
 
     int64_t nLastSend;
     int64_t nLastRecv;
@@ -747,12 +747,13 @@ public:
     // requires LOCK(cs_vRecvMsg)
     bool ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete);
 
-    // requires LOCK(cs_vRecvMsg)
     void SetRecvVersion(int nVersionIn)
     {
         nRecvVersion = nVersionIn;
-        BOOST_FOREACH(CNetMessage &msg, vRecvMsg)
-            msg.SetVersion(nVersionIn);
+    }
+    int GetRecvVersion()
+    {
+        return nRecvVersion;
     }
     void SetSendVersion(int nVersionIn)
     {

src/net_processing.cpp

@@ -2485,6 +2485,7 @@ bool ProcessMessages(CNode* pfrom, CConnman& connman, std::atomic<bool>& interru
         // at this point, any failure means we can delete the current message
         it++;
 
+        msg.SetVersion(pfrom->GetRecvVersion());
         // Scan for message start
         if (memcmp(msg.hdr.pchMessageStart, chainparams.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) {
             LogPrintf("PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%d\n", SanitizeString(msg.hdr.GetCommand()), pfrom->id);