i2pd/libi2pd/SSU2.h

/*
* Copyright (c) 2022, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#ifndef SSU2_H__
#define SSU2_H__

#include <memory>
#include <unordered_map>
#include "Crypto.h"
#include "RouterInfo.h"
#include "TransportSession.h"

namespace i2p
{
namespace transport
{
	const int SSU2_TERMINATION_TIMEOUT = 330; // 5.5 minutes

	enum SSU2MessageType
	{
		eSSU2SessionRequest = 0
	};

	class SSU2Server;
	class SSU2Session: public TransportSession, public std::enable_shared_from_this<SSU2Session>
	{
		union Header
		{
			uint64_t ll[2];
			uint8_t buf[16];
			struct
			{
				uint8_t connID[8];
				uint8_t packetNum[4];
				uint8_t type;
				uint8_t flags[3];
			} h;
		};
	
		public:

			SSU2Session (SSU2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter = nullptr,
				std::shared_ptr<const i2p::data::RouterInfo::Address> addr = nullptr, bool peerTest = false);
			~SSU2Session ();

		private:

			void SendSessionRequest ();
			void EncryptHeader (Header& h);
			void CreateHeaderMask (const uint8_t * kh1, const uint8_t * nonce1, const uint8_t * kh2, const uint8_t * nonce2);
		
		private:

			SSU2Server& m_Server;
			std::shared_ptr<i2p::crypto::X25519Keys> m_EphemeralKeys;
			std::unique_ptr<i2p::crypto::NoiseSymmetricState> m_NoiseState;
			std::shared_ptr<const i2p::data::RouterInfo::Address> m_Address;

			union 
			{
				uint64_t ll[2];
				uint8_t buf[16];
			} m_HeaderMask;
	};

	class SSU2Server
	{
		public:

			SSU2Server (int port) {};
			~SSU2Server () {};

			void AddSession (uint64_t connID, std::shared_ptr<SSU2Session> session);

		private:

			void ProcessNextPacket (uint8_t * buf, size_t len);
			
		private:

			std::unordered_map<uint64_t, std::shared_ptr<SSU2Session> > m_Sessions;
	};	
}
}

#endif