Introduce REQUIRED_SERVICES constant

src/main.cpp

@@ -4787,7 +4787,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         {
             boost::this_thread::interruption_point();
 
-            if (!(addr.nServices & NODE_NETWORK))
+            if ((addr.nServices & REQUIRED_SERVICES) != REQUIRED_SERVICES)
                 continue;
 
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)

src/net.cpp

@@ -1596,7 +1596,7 @@ void ThreadOpenConnections()
                 continue;
 
             // only connect to full nodes
-            if (!(addr.nServices & NODE_NETWORK))
+            if ((addr.nServices & REQUIRED_SERVICES) != REQUIRED_SERVICES)
                 continue;
 
             // only consider very recently tried nodes after 30 failed attempts

src/net.h

@@ -72,6 +72,8 @@ static const bool DEFAULT_FORCEDNSSEED = false;
 static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
 static const size_t DEFAULT_MAXSENDBUFFER    = 1 * 1000;
 
+static const ServiceFlags REQUIRED_SERVICES = NODE_NETWORK;
+
 // NOTE: When adjusting this, update rpcnet:setban's help ("24h")
 static const unsigned int DEFAULT_MISBEHAVING_BANTIME = 60 * 60 * 24;  // Default 24-hour ban