std::mt19937 for random. Congestion update timer variance

libi2pd/RouterContext.cpp

@@ -33,13 +33,14 @@ namespace i2p
 		m_ShareRatio (100), m_Status (eRouterStatusUnknown), m_StatusV6 (eRouterStatusUnknown),
 		m_Error (eRouterErrorNone), m_ErrorV6 (eRouterErrorNone),
 		m_Testing (false), m_TestingV6 (false), m_NetID (I2PD_NET_ID),
-		m_PublishReplyToken (0), m_IsHiddenMode (false)
+		m_PublishReplyToken (0), m_IsHiddenMode (false), 
+		m_Rng(i2p::util::GetMonotonicMicroseconds () % 1000000LL)
 	{
 	}
 
 	void RouterContext::Init ()
 	{
-		srand (i2p::util::GetMillisecondsSinceEpoch () % 1000);
+		srand (m_Rng () % 1000);
 		m_StartupTime = i2p::util::GetMonotonicSeconds ();
 
 		if (!Load ())
@@ -1359,7 +1360,7 @@ namespace i2p
 		{	
 			m_PublishTimer->cancel ();
 			m_PublishTimer->expires_from_now (boost::posix_time::seconds(ROUTER_INFO_PUBLISH_INTERVAL + 
-				rand () % ROUTER_INFO_PUBLISH_INTERVAL_VARIANCE));
+				m_Rng () % ROUTER_INFO_PUBLISH_INTERVAL_VARIANCE));
 			m_PublishTimer->async_wait (std::bind (&RouterContext::HandlePublishTimer,
 				this, std::placeholders::_1));
 		}	
@@ -1471,7 +1472,8 @@ namespace i2p
 		if (m_CongestionUpdateTimer)
 		{	
 			m_CongestionUpdateTimer->cancel ();
-			m_CongestionUpdateTimer->expires_from_now (boost::posix_time::seconds(ROUTER_INFO_CONGESTION_UPDATE_INTERVAL));
+			m_CongestionUpdateTimer->expires_from_now (boost::posix_time::seconds(
+				ROUTER_INFO_CONGESTION_UPDATE_INTERVAL + m_Rng () % ROUTER_INFO_CONGESTION_UPDATE_INTERVAL_VARIANCE));
 			m_CongestionUpdateTimer->async_wait (std::bind (&RouterContext::HandleCongestionUpdateTimer,
 				this, std::placeholders::_1));
 		}	

libi2pd/RouterContext.h

@@ -12,6 +12,7 @@
 #include <inttypes.h>
 #include <string>
 #include <memory>
+#include <random>
 #include <unordered_set>
 #include <boost/asio.hpp>
 #include "Identity.h"
@@ -36,7 +37,8 @@ namespace garlic
 	const int ROUTER_INFO_PUBLISH_INTERVAL_VARIANCE = 105;// in seconds
 	const int ROUTER_INFO_CONFIRMATION_TIMEOUT = 1600; // in milliseconds
 	const int ROUTER_INFO_MAX_PUBLISH_EXCLUDED_FLOODFILLS = 15;
-	const int ROUTER_INFO_CONGESTION_UPDATE_INTERVAL = 12*60; // in seconds
+	const int ROUTER_INFO_CONGESTION_UPDATE_INTERVAL = 11*60; // in seconds
+	const int ROUTER_INFO_CONGESTION_UPDATE_INTERVAL_VARIANCE = 130; // in seconds 
 	const int ROUTER_INFO_CLEANUP_INTERVAL = 102; // in seconds
 
 	enum RouterStatus
@@ -263,6 +265,7 @@ namespace garlic
 			uint32_t m_PublishReplyToken;
 			bool m_IsHiddenMode; // not publish
 			mutable std::mutex m_RouterInfoMutex;
+			std::mt19937 m_Rng;
 	};
 
 	extern RouterContext context;