From a05a54b38edba546dc77f9d60037ab4dcec1129e Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Mon, 7 Sep 2020 18:45:05 -0400
Subject: [PATCH] trim behind ECIESx25519 tags

---
 libi2pd/ECIESX25519AEADRatchetSession.cpp |  3 +++
 libi2pd/ECIESX25519AEADRatchetSession.h   |  6 ++++--
 libi2pd/Garlic.cpp                        | 21 ++++++++++++---------
 libi2pd/Garlic.h                          |  1 -
 4 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/libi2pd/ECIESX25519AEADRatchetSession.cpp b/libi2pd/ECIESX25519AEADRatchetSession.cpp
index 51ca9242..229578a1 100644
--- a/libi2pd/ECIESX25519AEADRatchetSession.cpp
+++ b/libi2pd/ECIESX25519AEADRatchetSession.cpp
@@ -657,7 +657,10 @@ namespace garlic
 				moreTags -= (receiveTagset->GetNextIndex () - index);
 			}	
 			if (moreTags > 0)
+			{	
 				GenerateMoreReceiveTags (receiveTagset, moreTags);
+				receiveTagset->MoveTrimBehind (moreTags >> 1); // /2
+			}	
 		}	
 		return true;
 	}
diff --git a/libi2pd/ECIESX25519AEADRatchetSession.h b/libi2pd/ECIESX25519AEADRatchetSession.h
index 73e129d7..c9f21463 100644
--- a/libi2pd/ECIESX25519AEADRatchetSession.h
+++ b/libi2pd/ECIESX25519AEADRatchetSession.h
@@ -56,10 +56,12 @@ namespace garlic
 			std::shared_ptr<ECIESX25519AEADRatchetSession> GetSession () { return m_Session.lock (); };
 			int GetTagSetID () const { return m_TagSetID; };
 			void SetTagSetID (int tagsetID) { m_TagSetID = tagsetID; };
+			void MoveTrimBehind (int offset) { m_TrimBehindIndex += offset; }; 
 
 			void Expire ();
 			bool IsExpired (uint64_t ts) const { return m_ExpirationTimestamp && ts > m_ExpirationTimestamp; };
-
+			bool IsIndexExpired (int index) const { return m_Session.expired () || index < m_TrimBehindIndex; };
+			
 		private:
 
 			union
@@ -73,7 +75,7 @@ namespace garlic
 
 			} m_KeyData;
 			uint8_t m_SessTagConstant[32], m_SymmKeyCK[32], m_CurrentSymmKeyCK[64], m_NextRootKey[32];
-			int m_NextIndex, m_NextSymmKeyIndex;
+			int m_NextIndex, m_NextSymmKeyIndex, m_TrimBehindIndex = 0;
 			std::unordered_map<int, i2p::data::Tag<32> > m_ItermediateSymmKeys;
 			std::weak_ptr<ECIESX25519AEADRatchetSession> m_Session;
 			int m_TagSetID = 0;
diff --git a/libi2pd/Garlic.cpp b/libi2pd/Garlic.cpp
index 84a0519e..6d50aa1e 100644
--- a/libi2pd/Garlic.cpp
+++ b/libi2pd/Garlic.cpp
@@ -802,14 +802,6 @@ namespace garlic
 			}
 		}
 		// ECIESx25519
-		for (auto it = m_ECIESx25519Tags.begin (); it != m_ECIESx25519Tags.end ();)
-		{
-			if (it->second.tagset->IsExpired (ts) || ts > it->second.creationTime + ECIESX25519_INCOMING_TAGS_EXPIRATION_TIMEOUT)
-				it = m_ECIESx25519Tags.erase (it);
-			else
-				++it;
-		}
-
 		for (auto it = m_ECIESx25519Sessions.begin (); it != m_ECIESx25519Sessions.end ();)
 		{
 			if (it->second->CheckExpired (ts))
@@ -820,6 +812,17 @@ namespace garlic
 			else
 				++it;
 		}
+
+		numExpiredTags = 0;
+		for (auto it = m_ECIESx25519Tags.begin (); it != m_ECIESx25519Tags.end ();)
+		{
+			if (it->second.tagset->IsExpired (ts) || it->second.tagset->IsIndexExpired (it->second.index))
+				it = m_ECIESx25519Tags.erase (it);
+			else
+				++it;
+		}
+		if (numExpiredTags > 0)
+			LogPrint (eLogDebug, "Garlic: ", numExpiredTags, " ECIESx25519 tags expired for ", GetIdentHash().ToBase64 ());
 	}
 
 	void GarlicDestination::RemoveDeliveryStatusSession (uint32_t msgID)
@@ -1009,7 +1012,7 @@ namespace garlic
 	{
 		auto index = tagset->GetNextIndex ();
 		uint64_t tag = tagset->GetNextSessionTag ();
-		m_ECIESx25519Tags.emplace (tag, ECIESX25519AEADRatchetIndexTagset{index, tagset, i2p::util::GetSecondsSinceEpoch ()});
+		m_ECIESx25519Tags.emplace (tag, ECIESX25519AEADRatchetIndexTagset{index, tagset});
 	}
 
 	void GarlicDestination::AddECIESx25519Session (const uint8_t * staticKey, ECIESX25519AEADRatchetSessionPtr session)
diff --git a/libi2pd/Garlic.h b/libi2pd/Garlic.h
index 2168ee81..b97eaab2 100644
--- a/libi2pd/Garlic.h
+++ b/libi2pd/Garlic.h
@@ -220,7 +220,6 @@ namespace garlic
 	{
 		int index;
 		RatchetTagSetPtr tagset;
-		uint64_t creationTime; // seconds since epoch
 	};
 
 	class GarlicDestination: public i2p::data::LocalDestination