i2pd/transport/SSU.h

#ifndef SSU_H__
#define SSU_H__

#include <inttypes.h>
#include <string.h>
#include <map>
#include <list>
#include <set>
#include <thread>
#include <mutex>
#include <boost/asio.hpp>
#include "aes.h"
#include "I2PEndian.h"
#include "Identity.h"
#include "RouterInfo.h"
#include "I2NPProtocol.h"
#include "SSUSession.h"

namespace i2p
{
namespace transport
{
    const int SSU_KEEP_ALIVE_INTERVAL = 30; // 30 seconds   
    const int SSU_PEER_TEST_TIMEOUT = 60; // 60 seconds     
    const int SSU_TO_INTRODUCER_SESSION_DURATION = 3600; // 1 hour
    const size_t SSU_MAX_NUM_INTRODUCERS = 3;

    struct SSUPacket
    {
        i2p::crypto::AESAlignedBuffer<1500> buf;
        boost::asio::ip::udp::endpoint from;
        size_t len;
    };  
    
    class SSUServer
    {
        public:

            SSUServer (int port);
            ~SSUServer ();
            void Start ();
            void Stop ();
            std::shared_ptr<SSUSession> GetSession (std::shared_ptr<const i2p::data::RouterInfo> router, bool peerTest = false);
            std::shared_ptr<SSUSession> FindSession (std::shared_ptr<const i2p::data::RouterInfo> router) const;
            std::shared_ptr<SSUSession> FindSession (const boost::asio::ip::udp::endpoint& e) const;
            std::shared_ptr<SSUSession> GetRandomEstablishedSession (std::shared_ptr<const SSUSession> excluded);
            void DeleteSession (std::shared_ptr<SSUSession> session);
            void DeleteAllSessions ();          

            boost::asio::io_service& GetService () { return m_Service; };
            boost::asio::io_service& GetServiceV6 () { return m_ServiceV6; };
            const boost::asio::ip::udp::endpoint& GetEndpoint () const { return m_Endpoint; };          
            void Send (const uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& to);
            void AddRelay (uint32_t tag, const boost::asio::ip::udp::endpoint& relay);
            std::shared_ptr<SSUSession> FindRelaySession (uint32_t tag);

            void NewPeerTest (uint32_t nonce, PeerTestParticipant role, std::shared_ptr<SSUSession> session = nullptr);
            PeerTestParticipant GetPeerTestParticipant (uint32_t nonce);
            std::shared_ptr<SSUSession> GetPeerTestSession (uint32_t nonce);
            void UpdatePeerTest (uint32_t nonce, PeerTestParticipant role);
            void RemovePeerTest (uint32_t nonce);

        private:

            void Run ();
            void RunV6 ();
            void RunReceivers ();
            void Receive ();
            void ReceiveV6 ();
            void HandleReceivedFrom (const boost::system::error_code& ecode, std::size_t bytes_transferred, SSUPacket * packet);
            void HandleReceivedFromV6 (const boost::system::error_code& ecode, std::size_t bytes_transferred, SSUPacket * packet);
            void HandleReceivedPackets (std::vector<SSUPacket *> packets);

            template<typename Filter>
            std::shared_ptr<SSUSession> GetRandomSession (Filter filter);
            
            std::set<SSUSession *> FindIntroducers (int maxNumIntroducers); 
            void ScheduleIntroducersUpdateTimer ();
            void HandleIntroducersUpdateTimer (const boost::system::error_code& ecode);

            void SchedulePeerTestsCleanupTimer ();
            void HandlePeerTestsCleanupTimer (const boost::system::error_code& ecode);

        private:

            struct PeerTest
            {
                uint64_t creationTime;
                PeerTestParticipant role;
                std::shared_ptr<SSUSession> session; // for Bob to Alice
            };  
            
            bool m_IsRunning;
            std::thread * m_Thread, * m_ThreadV6, * m_ReceiversThread;  
            boost::asio::io_service m_Service, m_ServiceV6, m_ReceiversService;
            boost::asio::io_service::work m_Work, m_WorkV6, m_ReceiversWork;
            boost::asio::ip::udp::endpoint m_Endpoint, m_EndpointV6;
            boost::asio::ip::udp::socket m_Socket, m_SocketV6;
            boost::asio::deadline_timer m_IntroducersUpdateTimer, m_PeerTestsCleanupTimer;
            std::list<boost::asio::ip::udp::endpoint> m_Introducers; // introducers we are connected to
            mutable std::mutex m_SessionsMutex;
            std::map<boost::asio::ip::udp::endpoint, std::shared_ptr<SSUSession> > m_Sessions;
            std::map<uint32_t, boost::asio::ip::udp::endpoint> m_Relays; // we are introducer
            std::map<uint32_t, PeerTest> m_PeerTests; // nonce -> creation time in milliseconds

        public:
            // for HTTP only
            const decltype(m_Sessions)& GetSessions () const { return m_Sessions; };
    };
}
}

#endif