net: Allow connecting to extra outbound peers

src/net.h

@@ -251,6 +251,19 @@ public:
     void GetBanned(banmap_t &banmap);
     void SetBanned(const banmap_t &banmap);
 
+    // This allows temporarily exceeding nMaxOutbound, with the goal of finding
+    // a peer that is better than all our current peers.
+    void SetTryNewOutboundPeer(bool flag);
+    bool GetTryNewOutboundPeer();
+
+    // Return the number of outbound peers we have in excess of our target (eg,
+    // if we previously called SetTryNewOutboundPeer(true), and have since set
+    // to false, we may have extra peers that we wish to disconnect). This may
+    // return a value less than (num_outbound_connections - num_outbound_slots)
+    // in cases where some outbound connections are not yet fully connected, or
+    // not yet fully disconnected.
+    int GetExtraOutboundCount();
+
     bool AddNode(const std::string& node);
     bool RemoveAddedNode(const std::string& node);
     std::vector<AddedNodeInfo> GetAddedNodeInfo();
@@ -413,6 +426,11 @@ private:
     std::thread threadOpenAddedConnections;
     std::thread threadOpenConnections;
     std::thread threadMessageHandler;
+
+    /** flag for deciding to connect to an extra outbound peer,
+     *  in excess of nMaxOutbound
+     *  This takes the place of a feeler connection */
+    std::atomic_bool m_try_another_outbound_peer;
 };
 extern std::unique_ptr<CConnman> g_connman;
 void Discover(boost::thread_group& threadGroup);