crypto.ratchet.inboundTags

libi2pd/Destination.cpp

@@ -56,6 +56,9 @@ namespace client
 				if (it != params->end ())
 					numTags = std::stoi(it->second);
 				LogPrint (eLogInfo, "Destination: parameters for tunnel set to: ", inQty, " inbound (", inLen, " hops), ", outQty, " outbound (", outLen, " hops), ", numTags, " tags");
+				it = params->find (I2CP_PARAM_RATCHET_INBOUND_TAGS);
+				if (it != params->end ())
+					SetNumRatchetInboundTags (std::stoi(it->second));
 				it = params->find (I2CP_PARAM_EXPLICIT_PEERS);
 				if (it != params->end ())
 				{

libi2pd/Destination.h

@@ -57,6 +57,8 @@ namespace client
 	const int STREAM_REQUEST_TIMEOUT = 60; //in seconds
 	const char I2CP_PARAM_TAGS_TO_SEND[] = "crypto.tagsToSend";
 	const int DEFAULT_TAGS_TO_SEND = 40;
+	const char I2CP_PARAM_RATCHET_INBOUND_TAGS[] = "crypto.ratchet.inboundTags";
+	const char I2CP_PARAM_RATCHET_OUTBOUND_TAGS[] = "crypto.ratchet.outboundTags"; // not used yet
 	const char I2CP_PARAM_INBOUND_NICKNAME[] = "inbound.nickname";
 	const char I2CP_PARAM_OUTBOUND_NICKNAME[] = "outbound.nickname";
 	const char I2CP_PARAM_LEASESET_TYPE[] = "i2cp.leaseSetType";

libi2pd/ECIESX25519AEADRatchetSession.cpp

@@ -341,7 +341,8 @@ namespace garlic
 			newTagset->SetTagSetID (tagsetID);
 			newTagset->DHInitialize (receiveTagset->GetNextRootKey (), tagsetKey);
 			newTagset->NextSessionTagRatchet ();
-			GenerateMoreReceiveTags (newTagset, ECIESX25519_MAX_NUM_GENERATED_TAGS);
+			GenerateMoreReceiveTags (newTagset, (GetOwner () && GetOwner ()->GetNumRatchetInboundTags () > 0) ?
+				GetOwner ()->GetNumRatchetInboundTags () : ECIESX25519_MAX_NUM_GENERATED_TAGS);
 			receiveTagset->Expire ();
 			LogPrint (eLogDebug, "Garlic: next receive tagset ", tagsetID, " created");
 		}
@@ -459,7 +460,8 @@ namespace garlic
 		m_SendTagset = std::make_shared<RatchetTagSet>(shared_from_this ());
 		m_SendTagset->DHInitialize (m_CK, keydata + 32); // tagset_ba = DH_INITIALIZE(chainKey, k_ba)
 		m_SendTagset->NextSessionTagRatchet ();
-		GenerateMoreReceiveTags (receiveTagset, ECIESX25519_MIN_NUM_GENERATED_TAGS);
+		GenerateMoreReceiveTags (receiveTagset, (GetOwner () && GetOwner ()->GetNumRatchetInboundTags () > 0) ?
+			GetOwner ()->GetNumRatchetInboundTags () : ECIESX25519_MIN_NUM_GENERATED_TAGS);
 		i2p::crypto::HKDF (keydata + 32, nullptr, 0, "AttachPayloadKDF", m_NSRKey, 32); // k = HKDF(k_ba, ZEROLEN, "AttachPayloadKDF", 32)
 		// encrypt payload
 		if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len, m_H, 32, m_NSRKey, nonce, out + offset, len + 16, true)) // encrypt
@@ -548,7 +550,8 @@ namespace garlic
 			auto receiveTagset = std::make_shared<RatchetTagSet>(shared_from_this ());
 			receiveTagset->DHInitialize (m_CK, keydata + 32); // tagset_ba = DH_INITIALIZE(chainKey, k_ba)
 			receiveTagset->NextSessionTagRatchet ();
-			GenerateMoreReceiveTags (receiveTagset, ECIESX25519_MIN_NUM_GENERATED_TAGS);
+			GenerateMoreReceiveTags (receiveTagset, (GetOwner () && GetOwner ()->GetNumRatchetInboundTags () > 0) ?
+				GetOwner ()->GetNumRatchetInboundTags () : ECIESX25519_MIN_NUM_GENERATED_TAGS);
 		}
 		i2p::crypto::HKDF (keydata + 32, nullptr, 0, "AttachPayloadKDF", keydata, 32); // k = HKDF(k_ba, ZEROLEN, "AttachPayloadKDF", 32)
 		// decrypt payload
@@ -610,11 +613,23 @@ namespace garlic
 			return false;
 		}
 		HandlePayload (payload, len - 16, receiveTagset, index);
-		int moreTags = ECIESX25519_MIN_NUM_GENERATED_TAGS + (index >> 2); // N/4
-		if (moreTags > ECIESX25519_MAX_NUM_GENERATED_TAGS) moreTags = ECIESX25519_MAX_NUM_GENERATED_TAGS;
-		moreTags -= (receiveTagset->GetNextIndex () - index);
-		if (moreTags > 0 && GetOwner ())
-			GenerateMoreReceiveTags (receiveTagset, moreTags);
+		if (GetOwner ())
+		{	
+			int moreTags = 0;
+			if (GetOwner ()->GetNumRatchetInboundTags () > 0) // override in settings?
+			{
+				if (receiveTagset->GetNextIndex () - index < GetOwner ()->GetNumRatchetInboundTags ()/2)
+					moreTags = GetOwner ()->GetNumRatchetInboundTags ();
+			}
+			else
+			{	
+				moreTags = ECIESX25519_MIN_NUM_GENERATED_TAGS + (index >> 2); // N/4
+				if (moreTags > ECIESX25519_MAX_NUM_GENERATED_TAGS) moreTags = ECIESX25519_MAX_NUM_GENERATED_TAGS;
+				moreTags -= (receiveTagset->GetNextIndex () - index);
+			}	
+			if (moreTags > 0)
+				GenerateMoreReceiveTags (receiveTagset, moreTags);
+		}	
 		return true;
 	}
 

libi2pd/Garlic.cpp

@@ -432,7 +432,8 @@ namespace garlic
 		return ret;
 	}
 
-	GarlicDestination::GarlicDestination (): m_NumTags (32) // 32 tags by default
+	GarlicDestination::GarlicDestination (): m_NumTags (32), // 32 tags by default
+		m_NumRatchetInboundTags (0) // 0 means standard
 	{
 		m_Ctx = BN_CTX_new ();
 	}

libi2pd/Garlic.h

@@ -232,6 +232,8 @@ namespace garlic
 			void CleanUp ();
 			void SetNumTags (int numTags) { m_NumTags = numTags; };
 			int GetNumTags () const { return m_NumTags; };
+			void SetNumRatchetInboundTags (int numTags) { m_NumRatchetInboundTags = numTags; };
+			int GetNumRatchetInboundTags () const { return m_NumRatchetInboundTags; };
 			std::shared_ptr<GarlicRoutingSession> GetRoutingSession (std::shared_ptr<const i2p::data::RoutingDestination> destination, bool attachLeaseSet);
 			void CleanupExpiredTags ();
 			void RemoveDeliveryStatusSession (uint32_t msgID);
@@ -278,6 +280,7 @@ namespace garlic
 			std::unordered_map<i2p::data::IdentHash, ElGamalAESSessionPtr> m_Sessions;
 			std::unordered_map<i2p::data::Tag<32>, ECIESX25519AEADRatchetSessionPtr> m_ECIESx25519Sessions; // static key -> session
 			// incoming
+			int m_NumRatchetInboundTags;
 			std::unordered_map<SessionTag, std::shared_ptr<AESDecryption>, std::hash<i2p::data::Tag<32> > > m_Tags;
 			std::unordered_map<uint64_t, ECIESX25519AEADRatchetIndexTagset> m_ECIESx25519Tags; // session tag -> session
 			// DeliveryStatus

libi2pd_client/ClientContext.cpp

@@ -461,6 +461,8 @@ namespace client
 		}
 		std::string explicitPeers = GetI2CPStringOption(section, I2CP_PARAM_EXPLICIT_PEERS, "");
 		if (explicitPeers.length () > 0) options[I2CP_PARAM_EXPLICIT_PEERS] = explicitPeers;
+		std::string ratchetInboundTags = GetI2CPStringOption(section, I2CP_PARAM_RATCHET_INBOUND_TAGS, "");
+		if (ratchetInboundTags.length () > 0) options[I2CP_PARAM_RATCHET_INBOUND_TAGS] = ratchetInboundTags;
 	}
 
 	void ClientContext::ReadI2CPOptionsFromConfig (const std::string& prefix, std::map<std::string, std::string>& options) const