Ensure CNode::addrKnown immediately takes little memory when we disconnect the node

src/main.cpp

@@ -7132,7 +7132,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
                 addr.nTime = nNow - 5 * 24 * 60 * 60;
-            pfrom->AddAddressKnown(addr);
+            pfrom->AddAddressIfNotAlreadyKnown(addr);
+
             ++num_proc;
             bool fReachable = IsReachable(addr);
             if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable())
@@ -7988,9 +7989,8 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
             vAddr.reserve(pto->vAddrToSend.size());
             BOOST_FOREACH(const CAddress& addr, pto->vAddrToSend)
             {
-                if (!pto->addrKnown.contains(addr.GetKey()))
+                if (pto->AddAddressIfNotAlreadyKnown(addr))
                 {
-                    pto->addrKnown.insert(addr.GetKey());
                     vAddr.push_back(addr);
 
                     if (vAddr.size() >= MAX_ADDR_TO_SEND)

src/net.cpp

@@ -556,6 +556,10 @@ void CNode::CloseSocketDisconnect()
             CloseSocket(hSocket);
         }
     }
+    {
+        LOCK(cs_addrKnown);
+        addrKnown.reset();
+    }
 
     // in case this fails, we'll empty the recv buffer when the CNode is deleted
     TRY_LOCK(cs_vRecvMsg, lockRecv);

src/net.h

@@ -432,6 +432,8 @@ public:
     CCriticalSection cs_filter;
     CBloomFilter* pfilter;
     int nRefCount;
+    CRollingBloomFilter addrKnown;
+    mutable CCriticalSection cs_addrKnown;
     NodeId id;
 
     /**
@@ -478,7 +480,6 @@ public:
 
     // flood relay
     std::vector<CAddress> vAddrToSend;
-    CRollingBloomFilter addrKnown;
     bool fGetAddr;
     std::set<uint256> setKnown;
 
@@ -561,11 +562,25 @@ public:
         nRefCount--;
     }
 
-
-
-    void AddAddressKnown(const CAddress& _addr)
+    bool AddAddressIfNotAlreadyKnown(const CAddress& addr)
     {
-        addrKnown.insert(_addr.GetKey());
+        LOCK(cs_addrKnown);
+        // Avoid adding to addrKnown after it has been reset in CloseSocketDisconnect.
+        if (fDisconnect) {
+            return false;
+        }
+        if (!addrKnown.contains(addr.GetKey())) {
+            addrKnown.insert(addr.GetKey());
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    bool IsAddressKnown(const CAddress& addr) const
+    {
+        LOCK(cs_addrKnown);
+        return addrKnown.contains(addr.GetKey());
     }
 
     void PushAddress(const CAddress& _addr)
@@ -578,7 +593,8 @@ public:
         // Known checking here is only to save space from duplicates.
         // SendMessages will filter it again for knowns that were added
         // after addresses were pushed.
-        if (_addr.IsValid() && !addrKnown.contains(_addr.GetKey()) && addr_format_supported) {
+        if (_addr.IsValid() && !IsAddressKnown(addr) && addr_format_supported) {
+
             if (vAddrToSend.size() >= MAX_ADDR_TO_SEND) {
                 vAddrToSend[insecure_rand() % vAddrToSend.size()] = _addr;
             } else {