Add a mutex lock to protect CNode::nRefCount (#1321)

* Add a mutex lock to protect CNode::nRefCount

* Added logging statement for CNode removal

Author: tgflynn

src/net.cpp

@@ -1050,6 +1050,9 @@ void ThreadSocketHandler()
                 if (pnode->fDisconnect ||
                     (pnode->GetRefCount() <= 0 && pnode->vRecvMsg.empty() && pnode->nSendSize == 0 && pnode->ssSend.empty()))
                 {
+                    LogPrintf("ThreadSocketHandler -- removing node: peer=%d addr=%s nRefCount=%d fNetworkNode=%d fInbound=%d fMasternode=%d\n",
+                              pnode->id, pnode->addr.ToString(), pnode->GetRefCount(), pnode->fNetworkNode, pnode->fInbound, pnode->fMasternode);
+
                     // remove from vNodes
                     vNodes.erase(remove(vNodes.begin(), vNodes.end(), pnode), vNodes.end());
 

src/net.h

@@ -436,6 +436,8 @@ class CNode
     static uint64_t nMaxOutboundLimit;
     static uint64_t nMaxOutboundTimeframe;
 
+    CCriticalSection cs_nRefCount;
+
     CNode(const CNode&);
     void operator=(const CNode&);
 
@@ -447,6 +449,7 @@ class CNode
 
     int GetRefCount()
     {
+        LOCK(cs_nRefCount);
         assert(nRefCount >= 0);
         return nRefCount;
     }
@@ -473,12 +476,14 @@ class CNode
 
     CNode* AddRef()
     {
+        LOCK(cs_nRefCount);
         nRefCount++;
         return this;
     }
 
     void Release()
     {
+        LOCK(cs_nRefCount);
         nRefCount--;
         assert(nRefCount >= 0);
     }