Merge pull request #2132 from PurpleI2P/openssl

recent changes

.github/workflows/build-windows.yml

@@ -231,7 +231,7 @@ jobs:
         cd MINGW-packages/mingw-w64-boost
         MINGW_ARCH=mingw32 makepkg-mingw -sCLf --noconfirm --nocheck
     - name: Install boost package
-      run: pacman --noconfirm -U MINGW-packages/mingw-w64-boost/mingw-w64-i686-*-any.pkg.tar.zst
+      run: pacman --noconfirm -U --overwrite MINGW-packages/mingw-w64-boost/mingw-w64-i686-*-any.pkg.tar.zst
 
     # Building i2pd
     - name: Build application

libi2pd/NTCP2.cpp

@@ -42,28 +42,29 @@ namespace transport
 		delete[] m_SessionConfirmedBuffer;
 	}
 
-	void NTCP2Establisher::KeyDerivationFunction1 (const uint8_t * pub, i2p::crypto::X25519Keys& priv, const uint8_t * rs, const uint8_t * epub)
+	bool NTCP2Establisher::KeyDerivationFunction1 (const uint8_t * pub, i2p::crypto::X25519Keys& priv, const uint8_t * rs, const uint8_t * epub)
 	{
 		i2p::crypto::InitNoiseXKState (*this, rs);
 		// h = SHA256(h || epub)
 		MixHash (epub, 32);
 		// x25519 between pub and priv
 		uint8_t inputKeyMaterial[32];
-		priv.Agree (pub, inputKeyMaterial);
+		if (!priv.Agree (pub, inputKeyMaterial)) return false;
 		MixKey (inputKeyMaterial);
+		return true;
 	}
 
-	void NTCP2Establisher::KDF1Alice ()
+	bool NTCP2Establisher::KDF1Alice ()
 	{
-		KeyDerivationFunction1 (m_RemoteStaticKey, *m_EphemeralKeys, m_RemoteStaticKey, GetPub ());
+		return KeyDerivationFunction1 (m_RemoteStaticKey, *m_EphemeralKeys, m_RemoteStaticKey, GetPub ());
 	}
 
-	void NTCP2Establisher::KDF1Bob ()
+	bool NTCP2Establisher::KDF1Bob ()
 	{
-		KeyDerivationFunction1 (GetRemotePub (), i2p::context.GetNTCP2StaticKeys (), i2p::context.GetNTCP2StaticPublicKey (), GetRemotePub ());
+		return KeyDerivationFunction1 (GetRemotePub (), i2p::context.GetNTCP2StaticKeys (), i2p::context.GetNTCP2StaticPublicKey (), GetRemotePub ());
 	}
 
-	void NTCP2Establisher::KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub)
+	bool NTCP2Establisher::KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub)
 	{
 		MixHash (sessionRequest + 32, 32); // encrypted payload
 
@@ -74,33 +75,35 @@ namespace transport
 
 		// x25519 between remote pub and ephemaral priv
 		uint8_t inputKeyMaterial[32];
-		m_EphemeralKeys->Agree (GetRemotePub (), inputKeyMaterial);
-
+		if (!m_EphemeralKeys->Agree (GetRemotePub (), inputKeyMaterial)) return false;
 		MixKey (inputKeyMaterial);
+		return true;
 	}
 
-	void NTCP2Establisher::KDF2Alice ()
+	bool NTCP2Establisher::KDF2Alice ()
 	{
-		KeyDerivationFunction2 (m_SessionRequestBuffer, m_SessionRequestBufferLen, GetRemotePub ());
+		return KeyDerivationFunction2 (m_SessionRequestBuffer, m_SessionRequestBufferLen, GetRemotePub ());
 	}
 
-	void NTCP2Establisher::KDF2Bob ()
+	bool NTCP2Establisher::KDF2Bob ()
 	{
-		KeyDerivationFunction2 (m_SessionRequestBuffer, m_SessionRequestBufferLen, GetPub ());
+		return KeyDerivationFunction2 (m_SessionRequestBuffer, m_SessionRequestBufferLen, GetPub ());
 	}
 
-	void NTCP2Establisher::KDF3Alice ()
+	bool NTCP2Establisher::KDF3Alice ()
 	{
 		uint8_t inputKeyMaterial[32];
-		i2p::context.GetNTCP2StaticKeys ().Agree (GetRemotePub (), inputKeyMaterial);
+		if (!i2p::context.GetNTCP2StaticKeys ().Agree (GetRemotePub (), inputKeyMaterial)) return false;
 		MixKey (inputKeyMaterial);
+		return true;
 	}
 
-	void NTCP2Establisher::KDF3Bob ()
+	bool NTCP2Establisher::KDF3Bob ()
 	{
 		uint8_t inputKeyMaterial[32];
-		m_EphemeralKeys->Agree (m_RemoteStaticKey, inputKeyMaterial);
+		if (!m_EphemeralKeys->Agree (m_RemoteStaticKey, inputKeyMaterial)) return false;
 		MixKey (inputKeyMaterial);
+		return true;
 	}
 
 	void NTCP2Establisher::CreateEphemeralKey ()
@@ -108,7 +111,7 @@ namespace transport
 		m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
 	}
 
-	void NTCP2Establisher::CreateSessionRequestMessage (std::mt19937& rng)
+	bool NTCP2Establisher::CreateSessionRequestMessage (std::mt19937& rng)
 	{
 		// create buffer and fill padding
 		auto paddingLength = rng () % (NTCP2_SESSION_REQUEST_MAX_SIZE - 64); // message length doesn't exceed 287 bytes
@@ -121,7 +124,7 @@ namespace transport
 		encryption.Encrypt (GetPub (), 32, m_SessionRequestBuffer); // X
 		encryption.GetIV (m_IV); // save IV for SessionCreated
 		// encryption key for next block
-		KDF1Alice ();
+		if (!KDF1Alice ()) return false;
 		// fill options
 		uint8_t options[32]; // actual options size is 16 bytes
 		memset (options, 0, 16);
@@ -147,9 +150,10 @@ namespace transport
 		uint8_t nonce[12];
 		memset (nonce, 0, 12); // set nonce to zero
 		i2p::crypto::AEADChaCha20Poly1305 (options, 16, GetH (), 32, GetK (), nonce, m_SessionRequestBuffer + 32, 32, true); // encrypt
+		return true;
 	}
 
-	void NTCP2Establisher::CreateSessionCreatedMessage (std::mt19937& rng)
+	bool NTCP2Establisher::CreateSessionCreatedMessage (std::mt19937& rng)
 	{
 		auto paddingLen = rng () % (NTCP2_SESSION_CREATED_MAX_SIZE - 64);
 		m_SessionCreatedBufferLen = paddingLen + 64;
@@ -160,7 +164,7 @@ namespace transport
 		encryption.SetIV (m_IV);
 		encryption.Encrypt (GetPub (), 32, m_SessionCreatedBuffer); // Y
 		// encryption key for next block (m_K)
-		KDF2Bob ();
+		if (!KDF2Bob ()) return false;
 		uint8_t options[16];
 		memset (options, 0, 16);
 		htobe16buf (options + 2, paddingLen); // padLen
@@ -169,7 +173,7 @@ namespace transport
 		uint8_t nonce[12];
 		memset (nonce, 0, 12); // set nonce to zero
 		i2p::crypto::AEADChaCha20Poly1305 (options, 16, GetH (), 32, GetK (), nonce, m_SessionCreatedBuffer + 32, 32, true); // encrypt
-
+		return true;
 	}
 
 	void NTCP2Establisher::CreateSessionConfirmedMessagePart1 (const uint8_t * nonce)
@@ -184,17 +188,18 @@ namespace transport
 		i2p::crypto::AEADChaCha20Poly1305 (i2p::context.GetNTCP2StaticPublicKey (), 32, GetH (), 32, GetK (), nonce, m_SessionConfirmedBuffer, 48, true); // encrypt
 	}
 
-	void NTCP2Establisher::CreateSessionConfirmedMessagePart2 (const uint8_t * nonce)
+	bool NTCP2Establisher::CreateSessionConfirmedMessagePart2 (const uint8_t * nonce)
 	{
 		// part 2
 		// update AD again
 		MixHash (m_SessionConfirmedBuffer, 48);
 		// encrypt m3p2, it must be filled in SessionRequest
-		KDF3Alice ();
+		if (!KDF3Alice ()) return false;
 		uint8_t * m3p2 = m_SessionConfirmedBuffer + 48;
 		i2p::crypto::AEADChaCha20Poly1305 (m3p2, m3p2Len - 16, GetH (), 32, GetK (), nonce, m3p2, m3p2Len, true); // encrypt
 		// update h again
 		MixHash (m3p2, m3p2Len); //h = SHA256(h || ciphertext)
+		return true;
 	}
 
 	bool NTCP2Establisher::ProcessSessionRequestMessage (uint16_t& paddingLen, bool& clockSkew)
@@ -207,7 +212,11 @@ namespace transport
 		decryption.Decrypt (m_SessionRequestBuffer, 32, GetRemotePub ());
 		decryption.GetIV (m_IV); // save IV for SessionCreated
 		// decryption key for next block
-		KDF1Bob ();
+		if (!KDF1Bob ())
+		{
+			LogPrint (eLogWarning, "NTCP2: SessionRequest KDF failed");
+			return false;
+		}	
 		// verify MAC and decrypt options block (32 bytes), use m_H as AD
 		uint8_t nonce[12], options[16];
 		memset (nonce, 0, 12); // set nonce to zero
@@ -262,7 +271,11 @@ namespace transport
 		decryption.SetIV (m_IV);
 		decryption.Decrypt (m_SessionCreatedBuffer, 32, GetRemotePub ());
 		// decryption key for next block (m_K)
-		KDF2Alice ();
+		if (!KDF2Alice ())
+		{
+			LogPrint (eLogWarning, "NTCP2: SessionCreated KDF failed");
+			return false;
+		}	
 		// decrypt and verify MAC
 		uint8_t payload[16];
 		uint8_t nonce[12];
@@ -309,7 +322,11 @@ namespace transport
 		// update AD again
 		MixHash (m_SessionConfirmedBuffer, 48);
 
-		KDF3Bob ();
+		if (!KDF3Bob ())
+		{
+			LogPrint (eLogWarning, "NTCP2: SessionConfirmed Part2 KDF failed");
+			return false;
+		}	
 		if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionConfirmedBuffer + 48, m3p2Len - 16, GetH (), 32, GetK (), nonce, m3p2Buf, m3p2Len - 16, false)) // decrypt
 			// calculate new h again for KDF data
 			MixHash (m_SessionConfirmedBuffer + 48, m3p2Len); // h = SHA256(h || ciphertext)
@@ -327,6 +344,7 @@ namespace transport
 		m_Server (server), m_Socket (m_Server.GetService ()),
 		m_IsEstablished (false), m_IsTerminated (false),
 		m_Establisher (new NTCP2Establisher),
+		m_SendKey (nullptr), m_ReceiveKey (nullptr),
 #if OPENSSL_SIPHASH
 		m_SendMDCtx(nullptr), m_ReceiveMDCtx (nullptr),
 #else
@@ -466,7 +484,12 @@ namespace transport
 
 	void NTCP2Session::SendSessionRequest ()
 	{
-		m_Establisher->CreateSessionRequestMessage (m_Server.GetRng ());
+		if (!m_Establisher->CreateSessionRequestMessage (m_Server.GetRng ()))
+		{
+			LogPrint (eLogWarning, "NTCP2: Send SessionRequest KDF failed");
+			boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));
+			return;
+		}	
 		// send message
 		m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch ();
 		boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionRequestBuffer, m_Establisher->m_SessionRequestBufferLen), boost::asio::transfer_all (),
@@ -558,7 +581,12 @@ namespace transport
 
 	void NTCP2Session::SendSessionCreated ()
 	{
-		m_Establisher->CreateSessionCreatedMessage (m_Server.GetRng ());
+		if (!m_Establisher->CreateSessionCreatedMessage (m_Server.GetRng ()))
+		{
+			LogPrint (eLogWarning, "NTCP2: Send SessionCreated KDF failed");
+			boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));
+			return;
+		}	
 		// send message
 		m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch ();
 		boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionCreatedBuffer, m_Establisher->m_SessionCreatedBufferLen), boost::asio::transfer_all (),
@@ -637,7 +665,12 @@ namespace transport
 		CreateNonce (1, nonce); // set nonce to 1
 		m_Establisher->CreateSessionConfirmedMessagePart1 (nonce);
 		memset (nonce, 0, 12); // set nonce back to 0
-		m_Establisher->CreateSessionConfirmedMessagePart2 (nonce);
+		if (!m_Establisher->CreateSessionConfirmedMessagePart2 (nonce))
+		{
+			LogPrint (eLogWarning, "NTCP2: Send SessionConfirmed Part2 KDF failed");
+			boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));
+			return;
+		}	
 		// send message
 		boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionConfirmedBuffer, m_Establisher->m3p2Len + 48), boost::asio::transfer_all (),
 			std::bind(&NTCP2Session::HandleSessionConfirmedSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
@@ -689,6 +722,7 @@ namespace transport
 
 	void NTCP2Session::HandleSessionConfirmedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
 	{
+		(void) bytes_transferred;
 		if (ecode)
 		{
 			LogPrint (eLogWarning, "NTCP2: SessionConfirmed read error: ", ecode.message ());
@@ -697,120 +731,141 @@ namespace transport
 		else
 		{
 			m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch () - m_HandshakeInterval;
-			LogPrint (eLogDebug, "NTCP2: SessionConfirmed received");
-			// part 1
-			uint8_t nonce[12];
-			CreateNonce (1, nonce);
-			if (m_Establisher->ProcessSessionConfirmedMessagePart1 (nonce))
-			{
-				// part 2
-				std::vector<uint8_t> buf(m_Establisher->m3p2Len - 16); // -MAC
-				memset (nonce, 0, 12); // set nonce to 0 again
-				if (m_Establisher->ProcessSessionConfirmedMessagePart2 (nonce, buf.data ())) // TODO:handle in establisher thread
+			boost::asio::post (m_Server.GetEstablisherService (), 
+				[s = shared_from_this ()] ()
 				{
-					KeyDerivationFunctionDataPhase ();
-					// Bob data phase keys
-					m_SendKey = m_Kba;
-					m_ReceiveKey = m_Kab;
-					SetSipKeys (m_Sipkeysba, m_Sipkeysab);
-					memcpy (m_ReceiveIV.buf, m_Sipkeysab + 16, 8);
-					memcpy (m_SendIV.buf, m_Sipkeysba + 16, 8);
-					// payload
-					// process RI
-					if (buf[0] != eNTCP2BlkRouterInfo)
-					{
-						LogPrint (eLogWarning, "NTCP2: Unexpected block ", (int)buf[0], " in SessionConfirmed");
-						Terminate ();
-						return;
-					}
-					auto size = bufbe16toh (buf.data () + 1);
-					if (size > buf.size () - 3 || size > i2p::data::MAX_RI_BUFFER_SIZE + 1)
-					{
-						LogPrint (eLogError, "NTCP2: Unexpected RouterInfo size ", size, " in SessionConfirmed");
-						Terminate ();
-						return;
-					}
-					// TODO: check flag
-					i2p::data::RouterInfo ri (buf.data () + 4, size - 1); // 1 byte block type + 2 bytes size + 1 byte flag
-					if (ri.IsUnreachable ())
-					{
-						LogPrint (eLogError, "NTCP2: RouterInfo verification failed in SessionConfirmed from ", GetRemoteEndpoint ());
-						SendTerminationAndTerminate (eNTCP2RouterInfoSignatureVerificationFail);
-						return;
-					}
-					LogPrint(eLogDebug, "NTCP2: SessionConfirmed from ", GetRemoteEndpoint (),
-						" (", i2p::data::GetIdentHashAbbreviation (ri.GetIdentHash ()), ")");
-					auto ts = i2p::util::GetMillisecondsSinceEpoch ();
-					if (ts > ri.GetTimestamp () + i2p::data::NETDB_MIN_EXPIRATION_TIMEOUT*1000LL) // 90 minutes
-					{
-						LogPrint (eLogError, "NTCP2: RouterInfo is too old in SessionConfirmed for ", (ts - ri.GetTimestamp ())/1000LL, " seconds");
-						SendTerminationAndTerminate (eNTCP2Message3Error);
-						return;
-					}
-					if (ts + i2p::data::NETDB_EXPIRATION_TIMEOUT_THRESHOLD*1000LL < ri.GetTimestamp ()) // 2 minutes
-					{
-						LogPrint (eLogError, "NTCP2: RouterInfo is from future for ", (ri.GetTimestamp () - ts)/1000LL, " seconds");
-						SendTerminationAndTerminate (eNTCP2Message3Error);
-						return;
-					}	
-					// update RouterInfo in netdb
-					auto ri1 = i2p::data::netdb.AddRouterInfo (ri.GetBuffer (), ri.GetBufferLen ()); // ri1 points to one from netdb now
-					if (!ri1)
-					{
-						LogPrint (eLogError, "NTCP2: Couldn't update RouterInfo from SessionConfirmed in netdb");
-						Terminate ();
-						return;
-					}
-					std::shared_ptr<i2p::data::RouterProfile> profile; // not null if older 
-					if (ri.GetTimestamp () + i2p::data::NETDB_EXPIRATION_TIMEOUT_THRESHOLD*1000LL < ri1->GetTimestamp ())
-					{	
-						// received RouterInfo is older than one in netdb
-						profile = i2p::data::GetRouterProfile (ri1->GetIdentHash ()); // retrieve profile	
-						if (profile && profile->IsDuplicated ())
-						{	
-							SendTerminationAndTerminate (eNTCP2Banned);
-							return;
-						}	
-					}
+					s->ProcessSessionConfirmed ();;
+				});	
+		}
+	}
 
-					auto addr = m_RemoteEndpoint.address ().is_v4 () ? ri1->GetNTCP2V4Address () :
-						(i2p::util::net::IsYggdrasilAddress (m_RemoteEndpoint.address ()) ? ri1->GetYggdrasilAddress () : ri1->GetNTCP2V6Address ());
-					if (!addr || memcmp (m_Establisher->m_RemoteStaticKey, addr->s, 32))
-					{
-						LogPrint (eLogError, "NTCP2: Wrong static key in SessionConfirmed");
-						Terminate ();
-						return;
-					}
-					if (addr->IsPublishedNTCP2 () && m_RemoteEndpoint.address () != addr->host &&
-					    (!m_RemoteEndpoint.address ().is_v6 () || (i2p::util::net::IsYggdrasilAddress (m_RemoteEndpoint.address ()) ?
-					     memcmp (m_RemoteEndpoint.address ().to_v6 ().to_bytes ().data () + 1, addr->host.to_v6 ().to_bytes ().data () + 1, 7) : // from the same yggdrasil subnet
-					     memcmp (m_RemoteEndpoint.address ().to_v6 ().to_bytes ().data (), addr->host.to_v6 ().to_bytes ().data (), 8)))) // temporary address
-					{
-						if (profile) // older router?
-							profile->Duplicated (); // mark router as duplicated in profile
-						else
-							LogPrint (eLogInfo, "NTCP2: Host mismatch between published address ", addr->host, " and actual endpoint ", m_RemoteEndpoint.address ());
-						SendTerminationAndTerminate (eNTCP2Banned);
-						return;
-					}
-					// TODO: process options
-
-					// ready to communicate
-					SetRemoteIdentity (ri1->GetRouterIdentity ());
-					if (m_Server.AddNTCP2Session (shared_from_this (), true))
-					{
-						Established ();
-						ReceiveLength ();
-					}
-					else
-						Terminate ();
+	void NTCP2Session::ProcessSessionConfirmed ()
+	{
+		// run on establisher thread
+		LogPrint (eLogDebug, "NTCP2: SessionConfirmed received");
+		// part 1
+		uint8_t nonce[12];
+		CreateNonce (1, nonce);
+		if (m_Establisher->ProcessSessionConfirmedMessagePart1 (nonce))
+		{
+			// part 2
+			auto buf = std::make_shared<std::vector<uint8_t> > (m_Establisher->m3p2Len - 16); // -MAC
+			memset (nonce, 0, 12); // set nonce to 0 again
+			if (m_Establisher->ProcessSessionConfirmedMessagePart2 (nonce, buf->data ())) // TODO:handle in establisher thread
+			{
+				// payload 
+				// RI block must be first 
+				if ((*buf)[0] != eNTCP2BlkRouterInfo)
+				{
+					LogPrint (eLogWarning, "NTCP2: Unexpected block ", (int)(*buf)[0], " in SessionConfirmed");
+					boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));
+					return;
 				}
-				else
-					Terminate ();
+				auto size = bufbe16toh (buf->data () + 1);
+				if (size > buf->size () - 3 || size > i2p::data::MAX_RI_BUFFER_SIZE + 1)
+				{
+					LogPrint (eLogError, "NTCP2: Unexpected RouterInfo size ", size, " in SessionConfirmed");
+					boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));
+					return;
+				}
+				boost::asio::post (m_Server.GetService (), 
+					[s = shared_from_this (), buf, size] ()
+					{
+						s->EstablishSessionAfterSessionConfirmed (buf, size);
+					});
 			}
 			else
-				Terminate ();
+				boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));
 		}
+		else
+			boost::asio::post (m_Server.GetService (), std::bind (&NTCP2Session::Terminate, shared_from_this ()));	
+	}	
+
+	void NTCP2Session::EstablishSessionAfterSessionConfirmed (std::shared_ptr<std::vector<uint8_t> > buf, size_t size)
+	{
+		// run on main NTCP2 thread
+		KeyDerivationFunctionDataPhase ();
+		// Bob data phase keys
+		m_SendKey = m_Kba;
+		m_ReceiveKey = m_Kab;
+		SetSipKeys (m_Sipkeysba, m_Sipkeysab);
+		memcpy (m_ReceiveIV.buf, m_Sipkeysab + 16, 8);
+		memcpy (m_SendIV.buf, m_Sipkeysba + 16, 8);
+		// we need to set keys for SendTerminationAndTerminate
+		// TODO: check flag
+		i2p::data::RouterInfo ri (buf->data () + 4, size - 1); // 1 byte block type + 2 bytes size + 1 byte flag
+		if (ri.IsUnreachable ())
+		{
+			LogPrint (eLogError, "NTCP2: RouterInfo verification failed in SessionConfirmed from ", GetRemoteEndpoint ());
+			SendTerminationAndTerminate (eNTCP2RouterInfoSignatureVerificationFail);
+			return;
+		}
+		LogPrint(eLogDebug, "NTCP2: SessionConfirmed from ", GetRemoteEndpoint (),
+			" (", i2p::data::GetIdentHashAbbreviation (ri.GetIdentHash ()), ")");
+		auto ts = i2p::util::GetMillisecondsSinceEpoch ();
+		if (ts > ri.GetTimestamp () + i2p::data::NETDB_MIN_EXPIRATION_TIMEOUT*1000LL) // 90 minutes
+		{
+			LogPrint (eLogError, "NTCP2: RouterInfo is too old in SessionConfirmed for ", (ts - ri.GetTimestamp ())/1000LL, " seconds");
+			SendTerminationAndTerminate (eNTCP2Message3Error);
+			return;
+		}
+		if (ts + i2p::data::NETDB_EXPIRATION_TIMEOUT_THRESHOLD*1000LL < ri.GetTimestamp ()) // 2 minutes
+		{
+			LogPrint (eLogError, "NTCP2: RouterInfo is from future for ", (ri.GetTimestamp () - ts)/1000LL, " seconds");
+			SendTerminationAndTerminate (eNTCP2Message3Error);
+			return;
+		}	
+		// update RouterInfo in netdb
+		auto ri1 = i2p::data::netdb.AddRouterInfo (ri.GetBuffer (), ri.GetBufferLen ()); // ri1 points to one from netdb now
+		if (!ri1)
+		{
+			LogPrint (eLogError, "NTCP2: Couldn't update RouterInfo from SessionConfirmed in netdb");
+			Terminate ();
+			return;
+		}
+		std::shared_ptr<i2p::data::RouterProfile> profile; // not null if older 
+		if (ri.GetTimestamp () + i2p::data::NETDB_EXPIRATION_TIMEOUT_THRESHOLD*1000LL < ri1->GetTimestamp ())
+		{	
+			// received RouterInfo is older than one in netdb
+			profile = i2p::data::GetRouterProfile (ri1->GetIdentHash ()); // retrieve profile	
+			if (profile && profile->IsDuplicated ())
+			{	
+				SendTerminationAndTerminate (eNTCP2Banned);
+				return;
+			}	
+		}
+		
+		auto addr = m_RemoteEndpoint.address ().is_v4 () ? ri1->GetNTCP2V4Address () :
+			(i2p::util::net::IsYggdrasilAddress (m_RemoteEndpoint.address ()) ? ri1->GetYggdrasilAddress () : ri1->GetNTCP2V6Address ());
+		if (!addr || memcmp (m_Establisher->m_RemoteStaticKey, addr->s, 32))
+		{
+			LogPrint (eLogError, "NTCP2: Wrong static key in SessionConfirmed");
+			Terminate ();
+			return;
+		}
+		if (addr->IsPublishedNTCP2 () && m_RemoteEndpoint.address () != addr->host &&
+		    (!m_RemoteEndpoint.address ().is_v6 () || (i2p::util::net::IsYggdrasilAddress (m_RemoteEndpoint.address ()) ?
+		     memcmp (m_RemoteEndpoint.address ().to_v6 ().to_bytes ().data () + 1, addr->host.to_v6 ().to_bytes ().data () + 1, 7) : // from the same yggdrasil subnet
+		     memcmp (m_RemoteEndpoint.address ().to_v6 ().to_bytes ().data (), addr->host.to_v6 ().to_bytes ().data (), 8)))) // temporary address
+		{
+			if (profile) // older router?
+				profile->Duplicated (); // mark router as duplicated in profile
+			else
+				LogPrint (eLogInfo, "NTCP2: Host mismatch between published address ", addr->host, " and actual endpoint ", m_RemoteEndpoint.address ());
+			SendTerminationAndTerminate (eNTCP2Banned);
+			return;
+		}
+		// TODO: process options block
+
+		// ready to communicate
+		SetRemoteIdentity (ri1->GetRouterIdentity ());
+		if (m_Server.AddNTCP2Session (shared_from_this (), true))
+		{
+			Established ();
+			ReceiveLength ();
+		}
+		else
+			Terminate ();
 	}	
 		
 	void NTCP2Session::SetSipKeys (const uint8_t * sendSipKey, const uint8_t * receiveSipKey)

libi2pd/NTCP2.h

@@ -95,21 +95,21 @@ namespace transport
 		const uint8_t * GetCK () const { return m_CK; };
 		const uint8_t * GetH () const { return m_H; };
 
-		void KDF1Alice ();
-		void KDF1Bob ();
-		void KDF2Alice ();
-		void KDF2Bob ();
-		void KDF3Alice (); // for SessionConfirmed part 2
-		void KDF3Bob ();
+		bool KDF1Alice ();
+		bool KDF1Bob ();
+		bool KDF2Alice ();
+		bool KDF2Bob ();
+		bool KDF3Alice (); // for SessionConfirmed part 2
+		bool KDF3Bob ();
 
-		void KeyDerivationFunction1 (const uint8_t * pub, i2p::crypto::X25519Keys& priv, const uint8_t * rs, const uint8_t * epub); // for SessionRequest, (pub, priv) for DH
-		void KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub); // for SessionCreate
+		bool KeyDerivationFunction1 (const uint8_t * pub, i2p::crypto::X25519Keys& priv, const uint8_t * rs, const uint8_t * epub); // for SessionRequest, (pub, priv) for DH
+		bool KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub); // for SessionCreate
 		void CreateEphemeralKey ();
 
-		void CreateSessionRequestMessage (std::mt19937& rng);
-		void CreateSessionCreatedMessage (std::mt19937& rng);
+		bool CreateSessionRequestMessage (std::mt19937& rng);
+		bool CreateSessionCreatedMessage (std::mt19937& rng);
 		void CreateSessionConfirmedMessagePart1 (const uint8_t * nonce);
-		void CreateSessionConfirmedMessagePart2 (const uint8_t * nonce);
+		bool CreateSessionConfirmedMessagePart2 (const uint8_t * nonce);
 
 		bool ProcessSessionRequestMessage (uint16_t& paddingLen, bool& clockSkew);
 		bool ProcessSessionCreatedMessage (uint16_t& paddingLen);
@@ -180,6 +180,8 @@ namespace transport
 			void HandleSessionCreatedPaddingReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
 			void HandleSessionConfirmedSent (const boost::system::error_code& ecode, std::size_t bytes_transferred);
 			void HandleSessionConfirmedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
+			void ProcessSessionConfirmed ();
+			void EstablishSessionAfterSessionConfirmed (std::shared_ptr<std::vector<uint8_t> > buf, size_t size);
 			
 			// data
 			void ReceiveLength ();

libi2pd/Streaming.cpp

@@ -73,7 +73,7 @@ namespace stream
 		m_LastConfirmedReceivedSequenceNumber (0), // for limit inbound speed
 		m_Status (eStreamStatusNew), m_IsIncoming (false), m_IsAckSendScheduled (false), m_IsNAcked (false), m_IsFirstACK (false), 
 		m_IsResendNeeded (false), m_IsFirstRttSample (false), m_IsSendTime (true), m_IsWinDropped (false),
-		m_IsTimeOutResend (false), m_IsImmediateAckRequested (false), m_IsRemoteLeaseChangeInProgress (false), m_LocalDestination (local),
+		m_IsTimeOutResend (false), m_IsImmediateAckRequested (false), m_IsRemoteLeaseChangeInProgress (false), m_DoubleWinIncCounter (false), m_LocalDestination (local),
 		m_RemoteLeaseSet (remote), m_ReceiveTimer (m_Service), m_SendTimer (m_Service), m_ResendTimer (m_Service),
 		m_AckSendTimer (m_Service), m_NumSentBytes (0), m_NumReceivedBytes (0), m_Port (port),
 		m_RTT (INITIAL_RTT), m_SlowRTT (INITIAL_RTT), m_SlowRTT2 (INITIAL_RTT), m_WindowSize (INITIAL_WINDOW_SIZE), m_LastWindowDropSize  (0),
@@ -101,7 +101,7 @@ namespace stream
 		m_LastConfirmedReceivedSequenceNumber (0), // for limit inbound speed
 		m_Status (eStreamStatusNew), m_IsIncoming (true), m_IsAckSendScheduled (false), m_IsNAcked (false), m_IsFirstACK (false), 
 		m_IsResendNeeded (false), m_IsFirstRttSample (false), m_IsSendTime (true), m_IsWinDropped (false),
-		m_IsTimeOutResend (false), m_IsImmediateAckRequested (false), m_IsRemoteLeaseChangeInProgress (false), m_LocalDestination (local),
+		m_IsTimeOutResend (false), m_IsImmediateAckRequested (false), m_IsRemoteLeaseChangeInProgress (false), m_DoubleWinIncCounter (false), m_LocalDestination (local),
 		m_ReceiveTimer (m_Service), m_SendTimer (m_Service), m_ResendTimer (m_Service), m_AckSendTimer (m_Service),
 		m_NumSentBytes (0), m_NumReceivedBytes (0), m_Port (0), m_RTT (INITIAL_RTT), m_SlowRTT (INITIAL_RTT), m_SlowRTT2 (INITIAL_RTT),
 		m_WindowSize (INITIAL_WINDOW_SIZE), m_LastWindowDropSize  (0), m_WindowDropTargetSize (0), m_WindowIncCounter (0), 
@@ -495,6 +495,7 @@ namespace stream
 			return;
 		}
 		int rttSample = INT_MAX;
+		int incCounter = 0;
 		m_IsNAcked = false;
 		m_IsResendNeeded = false;
 		int nackCount = packet->GetNACKCount ();
@@ -537,8 +538,7 @@ namespace stream
 				m_LocalDestination.DeletePacket (sentPacket);
 				acknowledged = true;
 				if (m_WindowSize < MAX_WINDOW_SIZE && !m_IsFirstACK)
-					if (m_RTT < m_LocalDestination.GetRandom () % INITIAL_RTO) // dirty
-						m_WindowIncCounter++;
+					incCounter++;
 			}
 			else
 				break;
@@ -552,7 +552,7 @@ namespace stream
 				m_SlowRTT2 = rttSample;
 				m_PrevRTTSample = rttSample;
 				m_Jitter = rttSample / 10; // 10%
-				m_Jitter += 5; // for low-latency connections
+				m_Jitter += 15; // for low-latency connections
 				m_IsFirstRttSample = false;
 			}
 			else
@@ -569,9 +569,23 @@ namespace stream
 					jitter = m_PrevRTTSample - rttSample;
 				else
 					jitter = rttSample / 10; // 10%
-				jitter += 5; // for low-latency connections
+				jitter += 15; // for low-latency connections
 				m_Jitter = (0.05 * jitter) + (1.0 - 0.05) * m_Jitter;
 			}
+			if (rttSample > m_SlowRTT)
+			{
+				incCounter = 0;
+				m_DoubleWinIncCounter = 1;
+			}
+			else if (rttSample < m_SlowRTT)
+			{
+				if (m_DoubleWinIncCounter)
+				{
+					incCounter = incCounter * 2;
+					m_DoubleWinIncCounter = 0;
+				}
+			}
+			m_WindowIncCounter = m_WindowIncCounter + incCounter;
 			//
 			// delay-based CC
 			if ((m_SlowRTT2 > m_SlowRTT + m_Jitter && rttSample > m_SlowRTT2 && rttSample > m_PrevRTTSample) && !m_IsWinDropped) // Drop window if RTT grows too fast, late detection
@@ -1297,8 +1311,6 @@ namespace stream
 				else if (m_IsResendNeeded) // resend packets
 					ResendPacket ();
 				// delay-based CC
-				else if (!m_IsWinDropped && int(m_SentPackets.size ()) == m_WindowSize) // we sending packets too fast, early detection
-					ProcessWindowDrop ();
 				else if (m_WindowSize > int(m_SentPackets.size ())) // send packets
 					SendBuffer ();
 			}

libi2pd/Streaming.h

@@ -19,6 +19,7 @@
 #include <mutex>
 #include <boost/asio.hpp>
 #include "Base.h"
+#include "Gzip.h"
 #include "I2PEndian.h"
 #include "Identity.h"
 #include "LeaseSet.h"
@@ -54,7 +55,7 @@ namespace stream
 	const size_t COMPRESSION_THRESHOLD_SIZE = 66;
 	const int MAX_NUM_RESEND_ATTEMPTS = 10;
 	const int INITIAL_WINDOW_SIZE = 10;
-	const int MIN_WINDOW_SIZE = 2;
+	const int MIN_WINDOW_SIZE = 3;
 	const int MAX_WINDOW_SIZE = 512;
 	const double RTT_EWMA_ALPHA = 0.25;
 	const double SLOWRTT_EWMA_ALPHA = 0.05;
@@ -274,6 +275,7 @@ namespace stream
 			bool m_IsTimeOutResend;
 			bool m_IsImmediateAckRequested;
 			bool m_IsRemoteLeaseChangeInProgress;
+			bool m_DoubleWinIncCounter;
 			StreamingDestination& m_LocalDestination;
 			std::shared_ptr<const i2p::data::IdentityEx> m_RemoteIdentity;
 			std::shared_ptr<const i2p::crypto::Verifier> m_TransientVerifier; // in case of offline key

libi2pd/TransitTunnel.h

@@ -73,7 +73,7 @@ namespace tunnel
 				const i2p::data::IdentHash& nextIdent, uint32_t nextTunnelID,
 				const i2p::crypto::AESKey& layerKey, const i2p::crypto::AESKey& ivKey):
 				TransitTunnel (receiveTunnelID, nextIdent, nextTunnelID,
-				layerKey, ivKey), m_Gateway(this) {};
+				layerKey, ivKey), m_Gateway(*this) {};
 
 			void SendTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage> msg) override;
 			void FlushTunnelDataMsgs () override;

libi2pd/Transports.cpp

@@ -447,28 +447,29 @@ namespace transport
 		return std::max (bwCongestionLevel, tbwCongestionLevel);
 	}
 
-	void Transports::SendMessage (const i2p::data::IdentHash& ident, std::shared_ptr<i2p::I2NPMessage> msg)
+	std::future<std::shared_ptr<TransportSession> > Transports::SendMessage (const i2p::data::IdentHash& ident, std::shared_ptr<i2p::I2NPMessage> msg)
 	{
 		if (m_IsOnline)
-			SendMessages (ident, { msg });
+			return SendMessages (ident, { msg });
+		return {}; // invalid future
 	}
 
-	void Transports::SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs)
+	std::future<std::shared_ptr<TransportSession> > Transports::SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs)
 	{
 		std::list<std::shared_ptr<i2p::I2NPMessage> > msgs1;
 		msgs.swap (msgs1);
-		SendMessages (ident, std::move (msgs1));
+		return SendMessages (ident, std::move (msgs1));
 	}
 
-	void Transports::SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >&& msgs)
+	std::future<std::shared_ptr<TransportSession> > Transports::SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >&& msgs)
 	{
-		boost::asio::post (*m_Service, [this, ident, msgs = std::move(msgs)] () mutable
+		return boost::asio::post (*m_Service, boost::asio::use_future ([this, ident, msgs = std::move(msgs)] () mutable
 			{
-				PostMessages (ident, msgs);
-			});	
+				return PostMessages (ident, msgs);
+			}));	
 	}	
 	
-	void Transports::PostMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs)
+	std::shared_ptr<TransportSession> Transports::PostMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs)
 	{
 		if (ident == i2p::context.GetRouterInfo ().GetIdentHash ())
 		{
@@ -476,9 +477,9 @@ namespace transport
 			for (auto& it: msgs)
 				m_LoopbackHandler.PutNextMessage (std::move (it));
 			m_LoopbackHandler.Flush ();
-			return;
+			return nullptr;
 		}
-		if(RoutesRestricted() && !IsRestrictedPeer(ident)) return;
+		if(RoutesRestricted() && !IsRestrictedPeer(ident)) return nullptr;
 		std::shared_ptr<Peer> peer;
 		{
 			std::lock_guard<std::mutex> l(m_PeersMutex);
@@ -489,13 +490,13 @@ namespace transport
 		if (!peer)
 		{
 			// check if not banned
-			if (i2p::data::IsRouterBanned (ident)) return; // don't create peer to unreachable router
+			if (i2p::data::IsRouterBanned (ident)) return nullptr; // don't create peer to unreachable router
 			// try to connect
 			bool connected = false;
 			try
 			{
 				auto r = netdb.FindRouter (ident);
-				if (r && (r->IsUnreachable () || !r->IsReachableFrom (i2p::context.GetRouterInfo ()))) return; // router found but non-reachable
+				if (r && (r->IsUnreachable () || !r->IsReachableFrom (i2p::context.GetRouterInfo ()))) return nullptr; // router found but non-reachable
 
 				peer = std::make_shared<Peer>(r, i2p::util::GetSecondsSinceEpoch ());
 				{	
@@ -509,12 +510,16 @@ namespace transport
 			{
 				LogPrint (eLogError, "Transports: PostMessages exception:", ex.what ());
 			}
-			if (!connected) return;
+			if (!connected) return nullptr;
 		}
 		
-		if (!peer) return;
+		if (!peer) return nullptr;
 		if (peer->IsConnected ())
-			peer->sessions.front ()->SendI2NPMessages (msgs);
+		{	
+			auto session = peer->sessions.front (); 
+			if (session) session->SendI2NPMessages (msgs);
+			return session;
+		}	
 		else
 		{
 			auto sz = peer->delayedMessages.size (); 	
@@ -527,7 +532,7 @@ namespace transport
 						LogPrint (eLogWarning, "Transports: Router ", ident.ToBase64 (), " is banned. Peer dropped");
 						std::lock_guard<std::mutex> l(m_PeersMutex);
 						m_Peers.erase (ident);
-						return;
+						return nullptr;
 					}	
 				}	
 				if (sz > MAX_NUM_DELAYED_MESSAGES/2)
@@ -549,6 +554,7 @@ namespace transport
 				m_Peers.erase (ident);
 			}
 		}
+		return nullptr;
 	}
 
 	bool Transports::ConnectToPeer (const i2p::data::IdentHash& ident, std::shared_ptr<Peer> peer)

libi2pd/Transports.h

@@ -11,6 +11,7 @@
 
 #include <thread>
 #include <mutex>
+#include <future>
 #include <condition_variable>
 #include <functional>
 #include <unordered_map>
@@ -143,9 +144,9 @@ namespace transport
 			std::shared_ptr<i2p::crypto::X25519Keys> GetNextX25519KeysPair ();
 			void ReuseX25519KeysPair (std::shared_ptr<i2p::crypto::X25519Keys> pair);
 
-			void SendMessage (const i2p::data::IdentHash& ident, std::shared_ptr<i2p::I2NPMessage> msg);
-			void SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs);
-			void SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >&& msgs);
+			std::future<std::shared_ptr<TransportSession> > SendMessage (const i2p::data::IdentHash& ident, std::shared_ptr<i2p::I2NPMessage> msg);
+			std::future<std::shared_ptr<TransportSession> > SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs);
+			std::future<std::shared_ptr<TransportSession> > SendMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >&& msgs);
 
 			void PeerConnected (std::shared_ptr<TransportSession> session);
 			void PeerDisconnected (std::shared_ptr<TransportSession> session);
@@ -189,7 +190,7 @@ namespace transport
 			void Run ();
 			void RequestComplete (std::shared_ptr<const i2p::data::RouterInfo> r, const i2p::data::IdentHash& ident);
 			void HandleRequestComplete (std::shared_ptr<const i2p::data::RouterInfo> r, i2p::data::IdentHash ident);
-			void PostMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs);
+			std::shared_ptr<TransportSession> PostMessages (const i2p::data::IdentHash& ident, std::list<std::shared_ptr<i2p::I2NPMessage> >& msgs);
 			bool ConnectToPeer (const i2p::data::IdentHash& ident, std::shared_ptr<Peer> peer);
 			void SetPriority (std::shared_ptr<Peer> peer) const;
 			void HandlePeerCleanupTimer (const boost::system::error_code& ecode);

libi2pd/Tunnel.h

@@ -139,7 +139,7 @@ namespace tunnel
 		public:
 
 			OutboundTunnel (std::shared_ptr<const TunnelConfig> config):
-				Tunnel (config), m_Gateway (this), m_EndpointIdentHash (config->GetLastIdentHash ()) {};
+				Tunnel (config), m_Gateway (*this), m_EndpointIdentHash (config->GetLastIdentHash ()) {};
 
 			void SendTunnelDataMsgTo (const uint8_t * gwHash, uint32_t gwTunnel, std::shared_ptr<i2p::I2NPMessage> msg);
 			virtual void SendTunnelDataMsgs (const std::vector<TunnelMessageBlock>& msgs); // multiple messages

libi2pd/TunnelGateway.cpp

@@ -220,21 +220,55 @@ namespace tunnel
 
 	void TunnelGateway::SendBuffer ()
 	{
+		// create list or tunnel messages
 		m_Buffer.CompleteCurrentTunnelDataMessage ();
 		std::list<std::shared_ptr<I2NPMessage> > newTunnelMsgs;
 		const auto& tunnelDataMsgs = m_Buffer.GetTunnelDataMsgs ();
 		for (auto& tunnelMsg : tunnelDataMsgs)
 		{
 			auto newMsg = CreateEmptyTunnelDataMsg (false);
-			m_Tunnel->EncryptTunnelMsg (tunnelMsg, newMsg);
-			htobe32buf (newMsg->GetPayload (), m_Tunnel->GetNextTunnelID ());
+			m_Tunnel.EncryptTunnelMsg (tunnelMsg, newMsg);
+			htobe32buf (newMsg->GetPayload (), m_Tunnel.GetNextTunnelID ());
 			newMsg->FillI2NPMessageHeader (eI2NPTunnelData);
 			if (tunnelMsg->onDrop) newMsg->onDrop = tunnelMsg->onDrop;
 			newTunnelMsgs.push_back (newMsg);
 			m_NumSentBytes += TUNNEL_DATA_MSG_SIZE;
 		}
 		m_Buffer.ClearTunnelDataMsgs ();
-		i2p::transport::transports.SendMessages (m_Tunnel->GetNextIdentHash (), std::move (newTunnelMsgs));
+
+		// send 
+		auto currentTransport = m_CurrentTransport.lock ();
+		if (!currentTransport)
+		{
+			// try to obtain transport from peding reequest or send thought transport is not complete
+			if (m_PendingTransport.valid ()) // pending request?
+			{
+				if (m_PendingTransport.wait_for(std::chrono::seconds(0)) == std::future_status::ready) 
+				{	
+					// pending request complete
+					currentTransport = m_PendingTransport.get (); // take tarnsports used in pending request
+					if (currentTransport)
+					{	
+						if (currentTransport->IsEstablished ()) 
+							m_CurrentTransport = currentTransport;
+						else
+							currentTransport = nullptr;
+					}
+				}	
+				else // still pending
+				{	
+					// send through transports, but don't update pedning transport
+					i2p::transport::transports.SendMessages (m_Tunnel.GetNextIdentHash (), std::move (newTunnelMsgs));
+					return;
+				}	
+			}
+		}
+		if (currentTransport) // session is good
+			// send to session directly
+			currentTransport->SendI2NPMessages (newTunnelMsgs);
+		else // no session yet
+			// send through transports
+			m_PendingTransport = i2p::transport::transports.SendMessages (m_Tunnel.GetNextIdentHash (), std::move (newTunnelMsgs));
 	}
 }
 }

libi2pd/TunnelGateway.h

@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013-2021, The PurpleI2P Project
+* Copyright (c) 2013-2024, The PurpleI2P Project
 *
 * This file is part of Purple i2pd project and licensed under BSD3
 *
@@ -12,7 +12,9 @@
 #include <inttypes.h>
 #include <vector>
 #include <memory>
+#include <future>
 #include "I2NPProtocol.h"
+#include "TransportSession.h"
 #include "TunnelBase.h"
 
 namespace i2p
@@ -45,7 +47,7 @@ namespace tunnel
 	{
 		public:
 
-			TunnelGateway (TunnelBase * tunnel):
+			TunnelGateway (TunnelBase& tunnel):
 				m_Tunnel (tunnel), m_NumSentBytes (0) {};
 			void SendTunnelDataMsg (const TunnelMessageBlock& block);
 			void PutTunnelDataMsg (const TunnelMessageBlock& block);
@@ -54,9 +56,11 @@ namespace tunnel
 
 		private:
 
-			TunnelBase * m_Tunnel;
+			TunnelBase& m_Tunnel;
 			TunnelGatewayBuffer m_Buffer;
 			size_t m_NumSentBytes;
+			std::weak_ptr<i2p::transport::TransportSession> m_CurrentTransport;
+			std::future<std::shared_ptr<i2p::transport::TransportSession> > m_PendingTransport;
 	};
 }
 }

libi2pd_client/I2PTunnel.cpp

@@ -375,10 +375,10 @@ namespace client
 	}
 
 	I2PServerTunnelConnectionHTTP::I2PServerTunnelConnectionHTTP (I2PService * owner, std::shared_ptr<i2p::stream::Stream> stream,
-		const boost::asio::ip::tcp::endpoint& target, const std::string& host,
+		const boost::asio::ip::tcp::endpoint& target, const std::string& host, const std::string& XI2P,
 	    std::shared_ptr<boost::asio::ssl::context> sslCtx):
-		I2PTunnelConnection (owner, stream, target, true, sslCtx), m_Host (host),
-		m_HeaderSent (false), m_ResponseHeaderSent (false), m_From (stream->GetRemoteIdentity ())
+		I2PTunnelConnection (owner, stream, target, true, sslCtx), m_Host (host), m_XI2P (XI2P),
+		m_HeaderSent (false), m_ResponseHeaderSent (false)
 	{
 		if (sslCtx)
 			SSL_set_tlsext_host_name(GetSSL ()->native_handle(), host.c_str ());
@@ -448,17 +448,12 @@ namespace client
 				if (!connection)
 					m_OutHeader << "Connection: close\r\n";
 				// add X-I2P fields
-				if (m_From)
-				{
-					m_OutHeader << X_I2P_DEST_B32 << ": " << context.GetAddressBook ().ToAddress(m_From->GetIdentHash ()) << "\r\n";
-					m_OutHeader << X_I2P_DEST_HASH << ": " << m_From->GetIdentHash ().ToBase64 () << "\r\n";
-					m_OutHeader << X_I2P_DEST_B64 << ": " << m_From->ToBase64 () << "\r\n";
-				}
+				m_OutHeader << m_XI2P;
+				// end of header
+				m_OutHeader << "\r\n"; 
 				
-				m_OutHeader << "\r\n"; // end of header
 				m_OutHeader << m_InHeader.str ().substr (m_InHeader.tellg ()); // data right after header
 				m_InHeader.str ("");
-				m_From = nullptr;
 				m_HeaderSent = true;
 				I2PTunnelConnection::Write ((uint8_t *)m_OutHeader.str ().c_str (), m_OutHeader.str ().length ());
 			}
@@ -876,7 +871,17 @@ namespace client
 
 	std::shared_ptr<I2PTunnelConnection> I2PServerTunnelHTTP::CreateI2PConnection (std::shared_ptr<i2p::stream::Stream> stream)
 	{
-		return std::make_shared<I2PServerTunnelConnectionHTTP> (this, stream, GetEndpoint (), m_Host, GetSSLCtx ());
+		if (m_XI2P.empty () || stream->GetRemoteIdentity () != m_From.lock ())
+		{
+			auto from = stream->GetRemoteIdentity ();
+			m_From = from;
+			std::stringstream ss;
+			ss << X_I2P_DEST_B32 << ": " << context.GetAddressBook ().ToAddress(from->GetIdentHash ()) << "\r\n";
+			ss << X_I2P_DEST_HASH << ": " << from->GetIdentHash ().ToBase64 () << "\r\n";
+			ss << X_I2P_DEST_B64 << ": " << from->ToBase64 () << "\r\n";
+			m_XI2P = ss.str ();
+		}	
+		return std::make_shared<I2PServerTunnelConnectionHTTP> (this, stream, GetEndpoint (), m_Host, m_XI2P, GetSSLCtx ());
 	}
 
 	I2PServerTunnelIRC::I2PServerTunnelIRC (const std::string& name, const std::string& address,

libi2pd_client/I2PTunnel.h

@@ -31,9 +31,9 @@ namespace client
 	const int I2P_TUNNEL_CONNECTION_MAX_IDLE = 3600; // in seconds
 	const int I2P_TUNNEL_DESTINATION_REQUEST_TIMEOUT = 10; // in seconds
 	// for HTTP tunnels
-	const char X_I2P_DEST_HASH[] = "X-I2P-DestHash"; // hash in base64
-	const char X_I2P_DEST_B64[] = "X-I2P-DestB64"; // full address in base64
-	const char X_I2P_DEST_B32[] = "X-I2P-DestB32"; // .b32.i2p address
+	constexpr char X_I2P_DEST_HASH[] = "X-I2P-DestHash"; // hash in base64
+	constexpr char X_I2P_DEST_B64[] = "X-I2P-DestB64"; // full address in base64
+	constexpr char X_I2P_DEST_B32[] = "X-I2P-DestB32"; // .b32.i2p address
 	const int I2P_TUNNEL_HTTP_MAX_HEADER_SIZE = 8192;
 
 	class I2PTunnelConnection: public I2PServiceHandler, public std::enable_shared_from_this<I2PTunnelConnection>
@@ -107,7 +107,7 @@ namespace client
 		public:
 
 			I2PServerTunnelConnectionHTTP (I2PService * owner, std::shared_ptr<i2p::stream::Stream> stream,
-				const boost::asio::ip::tcp::endpoint& target, const std::string& host,
+				const boost::asio::ip::tcp::endpoint& target, const std::string& host, const std::string& XI2P,
 			    std::shared_ptr<boost::asio::ssl::context> sslCtx = nullptr);
 
 		protected:
@@ -117,10 +117,9 @@ namespace client
 
 		private:
 
-			std::string m_Host;
+			std::string m_Host, m_XI2P;
 			std::stringstream m_InHeader, m_OutHeader;
 			bool m_HeaderSent, m_ResponseHeaderSent;
-			std::shared_ptr<const i2p::data::IdentityEx> m_From;
 	};
 
 	class I2PTunnelConnectionIRC: public I2PTunnelConnection
@@ -242,7 +241,8 @@ namespace client
 
 		private:
 
-			std::string m_Host;
+			std::string m_Host, m_XI2P;
+			std::weak_ptr<const i2p::data::IdentityEx> m_From;
 	};
 
 	class I2PServerTunnelIRC: public I2PServerTunnel