Deferred decode for HELLO to prevent HELLOcalypse under high load of new peers.

node/RuntimeEnvironment.hpp

@@ -32,6 +32,7 @@
 
 #include "Constants.hpp"
 #include "Identity.hpp"
+#include "Mutex.hpp"
 
 namespace ZeroTier {
 
@@ -44,6 +45,7 @@ class AntiRecursion;
 class NetworkController;
 class SelfAwareness;
 class Cluster;
+class DeferredPackets;
 
 /**
  * Holds global state for an instance of ZeroTier::Node
@@ -55,6 +57,7 @@ public:
 		node(n)
 		,identity()
 		,localNetworkController((NetworkController *)0)
+		,dp((DeferredPackets *)0)
 		,sw((Switch *)0)
 		,mc((Multicaster *)0)
 		,antiRec((AntiRecursion *)0)
@@ -77,6 +80,10 @@ public:
 	// This is set externally to an instance of this base class
 	NetworkController *localNetworkController;
 
+	// This is created if background threads call Node::backgroundThreadMain().
+	DeferredPackets *volatile dp; // can be read without lock but not written
+	Mutex dpSetLock;
+
 	/*
 	 * Order matters a bit here. These are constructed in this order
 	 * and then deleted in the opposite order on Node exit. The order ensures