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

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 {