implement SSU2HolPunchSession

libi2pd/SSU2.cpp

@@ -479,11 +479,13 @@ namespace transport
 	{
 		if (session)
 		{
-			m_Sessions.emplace (session->GetConnID (), session);
+			if (m_Sessions.emplace (session->GetConnID (), session).second)
+			{	
 				if (session->GetState () != eSSU2SessionStatePeerTest)
 					AddSessionByRouterHash (session);
 			}	
 		}
+	}
 
 	void SSU2Server::RemoveSession (uint64_t connID)
 	{
@@ -715,6 +717,9 @@ namespace transport
 					m_LastSession->SetRemoteEndpoint (senderEndpoint);
 					m_LastSession->ProcessPeerTest (buf, len);
 				break;
+				case eSSU2SessionStateHolePunch:
+					m_LastSession->ProcessFirstIncomingMessage (connID, buf, len); // SessionRequest
+				break;	
 				case eSSU2SessionStateClosing:
 					m_LastSession->ProcessData (buf, len, senderEndpoint); // we might receive termintaion block
 					if (m_LastSession && m_LastSession->GetState () == eSSU2SessionStateClosing)

libi2pd/SSU2OutOfSession.cpp

@@ -224,5 +224,63 @@ namespace transport
 			m_NumResends++;
 		}	
 	}	
+
+	SSU2HolePunchSession::SSU2HolePunchSession (SSU2Server& server, uint32_t nonce,
+		const boost::asio::ip::udp::endpoint& remoteEndpoint,
+		std::shared_ptr<const i2p::data::RouterInfo::Address> localAddr):
+		SSU2Session (server), // we create full incoming session
+		m_Nonce (nonce)
+	{
+		// we are Charlie
+		m_Token = GetServer ().GetIncomingToken (remoteEndpoint);
+		uint64_t destConnID = htobe64 (((uint64_t)nonce << 32) | nonce); // dest id
+		uint32_t sourceConnID = ~destConnID;
+		SetSourceConnID (sourceConnID);
+		SetDestConnID (destConnID);	
+		SetState (eSSU2SessionStateHolePunch);
+		SetRemoteEndpoint (remoteEndpoint);
+		SetAddress (localAddr);
+		SetTerminationTimeout (SSU2_RELAY_NONCE_EXPIRATION_TIMEOUT);	
+	}	
+
+	void SSU2HolePunchSession::SendHolePunch ()
+	{
+		auto addr = GetAddress ();
+		if (!addr) return;
+		auto& ep = GetRemoteEndpoint ();
+		LogPrint (eLogDebug, "SSU2: Sending HolePunch to ", ep);
+		Header header;
+		uint8_t h[32], payload[SSU2_MAX_PACKET_SIZE];
+		// fill packet
+		header.h.connID = GetDestConnID (); // dest id
+		RAND_bytes (header.buf + 8, 4); // random packet num
+		header.h.type = eSSU2HolePunch;
+		header.h.flags[0] = 2; // ver
+		header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID
+		header.h.flags[2] = 0; // flag
+		memcpy (h, header.buf, 16);
+		htobuf64 (h + 16, GetSourceConnID ()); // source id
+		RAND_bytes (h + 24, 8); // header token, to be ignored by Alice
+		// payload
+		payload[0] = eSSU2BlkDateTime;
+		htobe16buf (payload + 1, 4);
+		htobe32buf (payload + 3, (i2p::util::GetMillisecondsSinceEpoch () + 500)/1000);
+		size_t payloadSize = 7;
+		payloadSize += CreateAddressBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize, ep);
+		payloadSize += CreateRelayResponseBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize,
+			eSSU2RelayResponseCodeAccept, m_Nonce, m_Token, ep.address ().is_v4 ());
+		payloadSize += CreatePaddingBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize);
+		// encrypt
+		uint8_t n[12];
+		CreateNonce (be32toh (header.h.packetNum), n);
+		i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, h, 32, addr->i, n, payload, payloadSize + 16, true);
+		payloadSize += 16;
+		header.ll[0] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 24));
+		header.ll[1] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 12));
+		memset (n, 0, 12);
+		i2p::crypto::ChaCha20 (h + 16, 16, addr->i, n, h + 16);
+		// send
+		GetServer ().Send (header.buf, 16, h + 16, 16, payload, payloadSize, ep);
+	}	
 }
 }

libi2pd/SSU2OutOfSession.h

@@ -51,6 +51,21 @@ namespace transport
 			std::vector<uint8_t> m_SignedData; // for resends
 			boost::asio::deadline_timer m_PeerTestResendTimer;
 	};	
+
+	class SSU2HolePunchSession: public SSU2Session // Charlie
+	{
+		public:
+
+			SSU2HolePunchSession (SSU2Server& server, uint32_t nonce, const boost::asio::ip::udp::endpoint& remoteEndpoint,
+				std::shared_ptr<const i2p::data::RouterInfo::Address> localAddr);
+
+			void SendHolePunch ();
+			
+		private:
+
+			uint32_t m_Nonce;
+			uint64_t m_Token; // for RelayResponse block
+	};	
 }
 }
 	

libi2pd/SSU2Session.cpp

@@ -1352,46 +1352,6 @@ namespace transport
 		return true;
 	}
 
-	void SSU2Session::SendHolePunch (uint32_t nonce, const boost::asio::ip::udp::endpoint& ep,
-		const uint8_t * introKey, uint64_t token)
-	{
-		// we are Charlie
-		LogPrint (eLogDebug, "SSU2: Sending HolePunch to ", ep);
-		Header header;
-		uint8_t h[32], payload[SSU2_MAX_PACKET_SIZE];
-		// fill packet
-		header.h.connID = htobe64 (((uint64_t)nonce << 32) | nonce); // dest id
-		RAND_bytes (header.buf + 8, 4); // random packet num
-		header.h.type = eSSU2HolePunch;
-		header.h.flags[0] = 2; // ver
-		header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID
-		header.h.flags[2] = 0; // flag
-		memcpy (h, header.buf, 16);
-		uint64_t c = ~header.h.connID;
-		memcpy (h + 16, &c, 8); // source id
-		RAND_bytes (h + 24, 8); // token
-		// payload
-		payload[0] = eSSU2BlkDateTime;
-		htobe16buf (payload + 1, 4);
-		htobe32buf (payload + 3, (i2p::util::GetMillisecondsSinceEpoch () + 500)/1000);
-		size_t payloadSize = 7;
-		payloadSize += CreateAddressBlock (payload + payloadSize, m_MaxPayloadSize - payloadSize, ep);
-		payloadSize += CreateRelayResponseBlock (payload + payloadSize, m_MaxPayloadSize - payloadSize,
-			eSSU2RelayResponseCodeAccept, nonce, token, ep.address ().is_v4 ());
-		payloadSize += CreatePaddingBlock (payload + payloadSize, m_MaxPayloadSize - payloadSize);
-		// encrypt
-		uint8_t n[12];
-		CreateNonce (be32toh (header.h.packetNum), n);
-		i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, h, 32, introKey, n, payload, payloadSize + 16, true);
-		payloadSize += 16;
-		header.ll[0] ^= CreateHeaderMask (introKey, payload + (payloadSize - 24));
-		header.ll[1] ^= CreateHeaderMask (introKey, payload + (payloadSize - 12));
-		memset (n, 0, 12);
-		i2p::crypto::ChaCha20 (h + 16, 16, introKey, n, h + 16);
-		// send
-		m_Server.Send (header.buf, 16, h + 16, 16, payload, payloadSize, ep);
-	}
-
 	bool SSU2Session::ProcessHolePunch (uint8_t * buf, size_t len)
 	{
 		// we are Alice
@@ -1984,7 +1944,6 @@ namespace transport
 	void SSU2Session::HandleRelayIntro (const uint8_t * buf, size_t len, int attempts)
 	{
 		// we are Charlie
-		auto mts = i2p::util::GetMillisecondsSinceEpoch ();
 		SSU2RelayResponseCode code = eSSU2RelayResponseCodeAccept;
 		uint64_t token = 0;
 		bool isV4 = false;
@@ -2011,10 +1970,11 @@ namespace transport
 					{
 						if (m_Server.IsSupported (ep.address ()))
 						{
-							token = m_Server.GetIncomingToken (ep);
 							isV4 = ep.address ().is_v4 ();
-							SendHolePunch (bufbe32toh (buf + 33), ep, addr->i, token);
-							m_Server.AddConnectedRecently (ep, mts/1000);
+							auto holePunchSession = std::make_shared<SSU2HolePunchSession>(
+								m_Server, bufbe32toh (buf + 33), ep, addr); 
+							m_Server.AddSession (holePunchSession);
+							holePunchSession->SendHolePunch ();
 						}
 						else
 						{

libi2pd/SSU2Session.h

@@ -112,6 +112,7 @@ namespace transport
 		eSSU2SessionStateTerminated,
 		eSSU2SessionStateFailed,
 		eSSU2SessionStateIntroduced,
+		eSSU2SessionStateHolePunch,
 		eSSU2SessionStatePeerTest,
 		eSSU2SessionStateTokenRequestReceived
 	};
@@ -296,6 +297,8 @@ namespace transport
 			size_t CreatePaddingBlock (uint8_t * buf, size_t len, size_t minSize = 0);
 			size_t CreatePeerTestBlock (uint8_t * buf, size_t len, uint8_t msg, SSU2PeerTestCode code, const uint8_t * routerHash, const uint8_t * signedData, size_t signedDataLen);
 
+			size_t CreateRelayResponseBlock (uint8_t * buf, size_t len, SSU2RelayResponseCode code, uint32_t nonce, uint64_t token, bool v4);
+			
 		private:
 
 			void Terminate ();
@@ -320,7 +323,6 @@ namespace transport
 			uint32_t SendData (const uint8_t * buf, size_t len, uint8_t flags = 0); // returns packet num
 			void SendQuickAck ();
 			void SendTermination ();
-			void SendHolePunch (uint32_t nonce, const boost::asio::ip::udp::endpoint& ep, const uint8_t * introKey, uint64_t token);
 			void SendPathResponse (const uint8_t * data, size_t len);
 			void SendPathChallenge ();
 
@@ -352,7 +354,6 @@ namespace transport
 			size_t CreateFirstFragmentBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage> msg);
 			size_t CreateFollowOnFragmentBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage> msg, uint8_t& fragmentNum, uint32_t msgID);
 			size_t CreateRelayIntroBlock (uint8_t * buf, size_t len, const uint8_t * introData, size_t introDataLen);
-			size_t CreateRelayResponseBlock (uint8_t * buf, size_t len, SSU2RelayResponseCode code, uint32_t nonce, uint64_t token, bool v4);
 			size_t CreatePeerTestBlock (uint8_t * buf, size_t len, uint32_t nonce); // Alice
 			size_t CreateTerminationBlock (uint8_t * buf, size_t len);