use std::mt19937 instead rand()

libi2pd/SSU2.cpp

@@ -25,7 +25,7 @@ namespace transport
 		m_TerminationTimer (GetService ()), m_CleanupTimer (GetService ()), m_ResendTimer (GetService ()),
 		m_IntroducersUpdateTimer (GetService ()), m_IntroducersUpdateTimerV6 (GetService ()),
 		m_IsPublished (true), m_IsSyncClockFromPeers (true), m_PendingTimeOffset (0),
-		m_IsThroughProxy (false)
+		m_Rng(i2p::util::GetMonotonicMicroseconds ()%1000000LL), m_IsThroughProxy (false)
 	{
 	}
 
@@ -800,7 +800,7 @@ namespace transport
 		if (!indices.empty ())
 		{
 			if (indices.size () > 1)
-				std::shuffle (indices.begin(), indices.end(), std::mt19937(ts));
+				std::shuffle (indices.begin(), indices.end(), m_Rng);
 
 			for (auto ind: indices)
 			{
@@ -984,8 +984,8 @@ namespace transport
 	void SSU2Server::ScheduleResend (bool more)
 	{
 		m_ResendTimer.expires_from_now (boost::posix_time::milliseconds (more ? 
-		    (SSU2_RESEND_CHECK_MORE_TIMEOUT + rand () % SSU2_RESEND_CHECK_MORE_TIMEOUT_VARIANCE):
-			(SSU2_RESEND_CHECK_TIMEOUT + rand () % SSU2_RESEND_CHECK_TIMEOUT_VARIANCE)));
+		    (SSU2_RESEND_CHECK_MORE_TIMEOUT + m_Rng () % SSU2_RESEND_CHECK_MORE_TIMEOUT_VARIANCE):
+			(SSU2_RESEND_CHECK_TIMEOUT + m_Rng () % SSU2_RESEND_CHECK_TIMEOUT_VARIANCE)));
 		m_ResendTimer.async_wait (std::bind (&SSU2Server::HandleResendTimer,
 			this, std::placeholders::_1));
 	}
@@ -1057,7 +1057,7 @@ namespace transport
 	}
 
 	std::list<std::shared_ptr<SSU2Session> > SSU2Server::FindIntroducers (int maxNumIntroducers,
-		bool v4, const std::unordered_set<i2p::data::IdentHash>& excluded) const
+		bool v4, const std::unordered_set<i2p::data::IdentHash>& excluded)
 	{
 		std::list<std::shared_ptr<SSU2Session> > ret;
 		for (const auto& s : m_Sessions)
@@ -1074,7 +1074,7 @@ namespace transport
 			int sz = ret.size () - maxNumIntroducers;
 			for (int i = 0; i < sz; i++)
 			{
-				auto ind = rand () % ret.size ();
+				auto ind = m_Rng () % ret.size ();
 				auto it = ret.begin ();
 				std::advance (it, ind);
 				ret.erase (it);
@@ -1192,7 +1192,7 @@ namespace transport
 		if (m_IsPublished)
 		{
 			m_IntroducersUpdateTimer.expires_from_now (boost::posix_time::seconds(
-				SSU2_KEEP_ALIVE_INTERVAL + rand () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE));
+				SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE));
 			m_IntroducersUpdateTimer.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
 				this, std::placeholders::_1, true));
 		}
@@ -1206,7 +1206,7 @@ namespace transport
 			i2p::context.ClearSSU2Introducers (true);
 			m_Introducers.clear ();
 			m_IntroducersUpdateTimer.expires_from_now (boost::posix_time::seconds(
-				(SSU2_KEEP_ALIVE_INTERVAL + rand () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE)/2));
+				(SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE)/2));
 			m_IntroducersUpdateTimer.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
 				this, std::placeholders::_1, true));
 		}
@@ -1217,7 +1217,7 @@ namespace transport
 		if (m_IsPublished)
 		{
 			m_IntroducersUpdateTimerV6.expires_from_now (boost::posix_time::seconds(
-				SSU2_KEEP_ALIVE_INTERVAL + rand () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE));
+				SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE));
 			m_IntroducersUpdateTimerV6.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
 				this, std::placeholders::_1, false));
 		}
@@ -1231,7 +1231,7 @@ namespace transport
 			i2p::context.ClearSSU2Introducers (false);
 			m_IntroducersV6.clear ();
 			m_IntroducersUpdateTimerV6.expires_from_now (boost::posix_time::seconds(
-				(SSU2_KEEP_ALIVE_INTERVAL + rand () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE)/2));
+				(SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE)/2));
 			m_IntroducersUpdateTimerV6.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
 				this, std::placeholders::_1, false));
 		}

libi2pd/SSU2.h

@@ -12,6 +12,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include <mutex>
+#include <random>
 #include "util.h"
 #include "SSU2Session.h"
 #include "Socks5.h"
@@ -69,6 +70,7 @@ namespace transport
 			bool UsesProxy () const { return m_IsThroughProxy; };
 			bool IsSupported (const boost::asio::ip::address& addr) const;
 			uint16_t GetPort (bool v4) const;
+			std::mt19937& GetRng () { return m_Rng; }
 			bool IsSyncClockFromPeers () const { return m_IsSyncClockFromPeers; };
 			void AdjustTimeOffset (int64_t offset, std::shared_ptr<const i2p::data::IdentityEx> from);
 
@@ -128,7 +130,7 @@ namespace transport
 
 			void ConnectThroughIntroducer (std::shared_ptr<SSU2Session> session);
 			std::list<std::shared_ptr<SSU2Session> > FindIntroducers (int maxNumIntroducers,
-				bool v4, const std::unordered_set<i2p::data::IdentHash>& excluded) const;
+				bool v4, const std::unordered_set<i2p::data::IdentHash>& excluded);
 			void UpdateIntroducers (bool v4);
 			void ScheduleIntroducersUpdateTimer ();
 			void HandleIntroducersUpdateTimer (const boost::system::error_code& ecode, bool v4);
@@ -168,6 +170,7 @@ namespace transport
 			bool m_IsSyncClockFromPeers;
 			int64_t m_PendingTimeOffset; // during peer test
 			std::shared_ptr<const i2p::data::IdentityEx> m_PendingTimeOffsetFrom;
+			std::mt19937 m_Rng;
 
 			// proxy
 			bool m_IsThroughProxy;

libi2pd/SSU2Session.cpp

@@ -516,7 +516,7 @@ namespace transport
 			else
 				extraSize -= packet->payloadSize;
 		}
-		size_t offset = extraSize > 0 ? (rand () % extraSize) : 0;
+		size_t offset = extraSize > 0 ? (m_Server.GetRng ()() % extraSize) : 0;
 		if (offset + packet->payloadSize >= m_MaxPayloadSize) offset = 0;
 		auto size = CreateFirstFragmentBlock (packet->payload + packet->payloadSize, m_MaxPayloadSize - offset - packet->payloadSize, msg);
 		if (!size) return false;
@@ -528,7 +528,7 @@ namespace transport
 		uint8_t fragmentNum = 0;
 		while (msg->offset < msg->len)
 		{
-			offset = extraSize > 0 ? (rand () % extraSize) : 0;
+			offset = extraSize > 0 ? (m_Server.GetRng ()() % extraSize) : 0;
 			packet = m_Server.GetSentPacketsPool ().AcquireShared ();
 			packet->payloadSize = CreateFollowOnFragmentBlock (packet->payload, m_MaxPayloadSize - offset, msg, fragmentNum, msgID);
 			extraSize -= offset;
@@ -934,7 +934,7 @@ namespace transport
 		{
 			if (payloadSize > m_MaxPayloadSize - 48)
 			{
-				payloadSize = m_MaxPayloadSize - 48 - (rand () % 16);
+				payloadSize = m_MaxPayloadSize - 48 - (m_Server.GetRng ()() % 16);
 				if (m_SentHandshakePacket->payloadSize - payloadSize < 24)
 					payloadSize -= 24;
 			}
@@ -2695,7 +2695,7 @@ namespace transport
 	size_t SSU2Session::CreatePaddingBlock (uint8_t * buf, size_t len, size_t minSize)
 	{
 		if (len < 3 || len < minSize) return 0;
-		size_t paddingSize = rand () & 0x0F; // 0 - 15
+		size_t paddingSize = m_Server.GetRng ()() & 0x0F; // 0 - 15
 		if (paddingSize + 3 > len) paddingSize = len - 3;
 		else if (paddingSize + 3 < minSize) paddingSize = minSize - 3;
 		buf[0] = eSSU2BlkPadding;
@@ -2981,7 +2981,7 @@ namespace transport
 	{
 		uint8_t payload[SSU2_MAX_PACKET_SIZE];
 		payload[0] = eSSU2BlkPathChallenge;
-		size_t len = rand () % (m_MaxPayloadSize - 3);
+		size_t len = m_Server.GetRng ()() % (m_MaxPayloadSize - 3);
 		htobe16buf (payload + 1, len);
 		if (len > 0)
 		{