From b8d74dab477e712b4c64c376f08147414d7b3d69 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Sun, 2 Feb 2025 16:49:37 -0500
Subject: [PATCH] recreate tunnels in random order

---
 libi2pd/Tunnel.cpp | 59 ++++++++++++++++++++++++++++++++++++----------
 libi2pd/Tunnel.h   |  7 ++++--
 2 files changed, 51 insertions(+), 15 deletions(-)

diff --git a/libi2pd/Tunnel.cpp b/libi2pd/Tunnel.cpp
index 0d3f67db..f8be27ec 100644
--- a/libi2pd/Tunnel.cpp
+++ b/libi2pd/Tunnel.cpp
@@ -281,6 +281,21 @@ namespace tunnel
 		m_Endpoint.HandleDecryptedTunnelDataMsg (msg);
 	}
 
+	bool InboundTunnel::Recreate ()
+	{
+		if (!IsRecreated ())
+		{
+			auto pool = GetTunnelPool ();
+			if (pool)
+			{
+				SetRecreated (true);
+				pool->RecreateInboundTunnel (std::static_pointer_cast<InboundTunnel>(shared_from_this ()));
+				return true;
+			}	
+		}
+		return false;
+	}	
+		
 	ZeroHopsInboundTunnel::ZeroHopsInboundTunnel ():
 		InboundTunnel (std::make_shared<ZeroHopsTunnelConfig> ()),
 		m_NumReceivedBytes (0)
@@ -331,6 +346,21 @@ namespace tunnel
 		LogPrint (eLogError, "Tunnel: Incoming message for outbound tunnel ", GetTunnelID ());
 	}
 
+	bool OutboundTunnel::Recreate ()
+	{
+		if (!IsRecreated ())
+		{
+			auto pool = GetTunnelPool ();
+			if (pool)
+			{
+				SetRecreated (true);
+				pool->RecreateOutboundTunnel (std::static_pointer_cast<OutboundTunnel>(shared_from_this ()));
+				return true;
+			}	
+		}
+		return false;
+	}
+		
 	ZeroHopsOutboundTunnel::ZeroHopsOutboundTunnel ():
 		OutboundTunnel (std::make_shared<ZeroHopsTunnelConfig> ()),
 		m_NumSentBytes (0)
@@ -437,7 +467,7 @@ namespace tunnel
 	std::shared_ptr<OutboundTunnel> Tunnels::GetNextOutboundTunnel ()
 	{
 		if (m_OutboundTunnels.empty ()) return nullptr;
-		uint32_t ind = rand () % m_OutboundTunnels.size (), i = 0;
+		uint32_t ind = m_Rng () % m_OutboundTunnels.size (), i = 0;
 		std::shared_ptr<OutboundTunnel> tunnel;
 		for (const auto& it: m_OutboundTunnels)
 		{
@@ -714,8 +744,17 @@ namespace tunnel
 	void Tunnels::ManageTunnels (uint64_t ts)
 	{
 		ManagePendingTunnels (ts);
-		ManageInboundTunnels (ts);
-		ManageOutboundTunnels (ts);
+		std::vector<std::shared_ptr<Tunnel> > tunnelsToRecreate;
+		ManageInboundTunnels (ts, tunnelsToRecreate);
+		ManageOutboundTunnels (ts, tunnelsToRecreate);
+		// rec-create in random order
+		if (!tunnelsToRecreate.empty ())
+		{	
+			if (tunnelsToRecreate.size () > 1)
+				std::shuffle (tunnelsToRecreate.begin(), tunnelsToRecreate.end(), m_Rng);
+			for (auto& it: tunnelsToRecreate)
+				it->Recreate ();
+		}	
 	}
 
 	void Tunnels::ManagePendingTunnels (uint64_t ts)
@@ -778,7 +817,7 @@ namespace tunnel
 		}
 	}
 
-	void Tunnels::ManageOutboundTunnels (uint64_t ts)
+	void Tunnels::ManageOutboundTunnels (uint64_t ts, std::vector<std::shared_ptr<Tunnel> >& toRecreate)
 	{
 		for (auto it = m_OutboundTunnels.begin (); it != m_OutboundTunnels.end ();)
 		{
@@ -802,10 +841,7 @@ namespace tunnel
 						auto pool = tunnel->GetTunnelPool ();
 						// let it die if the tunnel pool has been reconfigured and this is old
 						if (pool && tunnel->GetNumHops() == pool->GetNumOutboundHops())
-						{
-							tunnel->SetRecreated (true);
-							pool->RecreateOutboundTunnel (tunnel);
-						}
+							toRecreate.push_back (tunnel);
 					}
 					if (ts + TUNNEL_EXPIRATION_THRESHOLD > tunnel->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
 						tunnel->SetState (eTunnelStateExpiring);
@@ -830,7 +866,7 @@ namespace tunnel
 		}
 	}
 
-	void Tunnels::ManageInboundTunnels (uint64_t ts)
+	void Tunnels::ManageInboundTunnels (uint64_t ts, std::vector<std::shared_ptr<Tunnel> >& toRecreate)
 	{
 		for (auto it = m_InboundTunnels.begin (); it != m_InboundTunnels.end ();)
 		{
@@ -854,10 +890,7 @@ namespace tunnel
 						auto pool = tunnel->GetTunnelPool ();
 						// let it die if the tunnel pool was reconfigured and has different number of hops
 						if (pool && tunnel->GetNumHops() == pool->GetNumInboundHops())
-						{
-							tunnel->SetRecreated (true);
-							pool->RecreateInboundTunnel (tunnel);
-						}
+							toRecreate.push_back (tunnel);
 					}
 
 					if (ts + TUNNEL_EXPIRATION_THRESHOLD > tunnel->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
diff --git a/libi2pd/Tunnel.h b/libi2pd/Tunnel.h
index 0cb87ace..5d21cd8b 100644
--- a/libi2pd/Tunnel.h
+++ b/libi2pd/Tunnel.h
@@ -99,6 +99,7 @@ namespace tunnel
 			void SetRecreated (bool recreated) { m_IsRecreated = recreated; };
 			int GetNumHops () const { return m_Hops.size (); };
 			virtual bool IsInbound() const = 0;
+			virtual bool Recreate () = 0;
 
 			std::shared_ptr<TunnelPool> GetTunnelPool () const { return m_Pool; };
 			void SetTunnelPool (std::shared_ptr<TunnelPool> pool) { m_Pool = pool; };
@@ -150,6 +151,7 @@ namespace tunnel
 			void HandleTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage>&& tunnelMsg) override;
 
 			bool IsInbound() const override { return false; }
+			bool Recreate () override;
 
 		private:
 
@@ -166,6 +168,7 @@ namespace tunnel
 			void HandleTunnelDataMsg (std::shared_ptr<I2NPMessage>&& msg) override;
 			virtual size_t GetNumReceivedBytes () const { return m_Endpoint.GetNumReceivedBytes (); };
 			bool IsInbound() const override { return true; }
+			bool Recreate () override;
 
 			// override TunnelBase
 			void Cleanup () override { m_Endpoint.Cleanup (); };
@@ -262,8 +265,8 @@ namespace tunnel
 			
 			void Run ();
 			void ManageTunnels (uint64_t ts);
-			void ManageOutboundTunnels (uint64_t ts);
-			void ManageInboundTunnels (uint64_t ts);
+			void ManageOutboundTunnels (uint64_t ts, std::vector<std::shared_ptr<Tunnel> >& toRecreate);
+			void ManageInboundTunnels (uint64_t ts, std::vector<std::shared_ptr<Tunnel> >& toRecreate);
 			void ManagePendingTunnels (uint64_t ts);
 			template<class PendingTunnels>
 			void ManagePendingTunnels (PendingTunnels& pendingTunnels, uint64_t ts);