I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#ifndef SSU_H__
#define SSU_H__
#include <inttypes.h>
#include <string.h>
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#include <map>
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#include <list>
#include <set>
#include <thread>
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#include <boost/asio.hpp>
#include "aes.h"
#include "I2PEndian.h"
#include "Identity.h"
#include "RouterInfo.h"
#include "I2NPProtocol.h"
#include "TransportSession.h"
#include "SSUData.h"
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namespace i2p
{
namespace transport
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{
#pragma pack(1)
struct SSUHeader
{
uint8_t mac[16];
uint8_t iv[16];
uint8_t flag;
uint32_t time;
uint8_t GetPayloadType () const { return flag >> 4; };
};
#pragma pack()
const int SSU_CONNECT_TIMEOUT = 5; // 5 seconds
const int SSU_TERMINATION_TIMEOUT = 330; // 5.5 minutes
const int SSU_KEEP_ALIVE_INTERVAL = 30; // 30 seconds
const int SSU_TO_INTRODUCER_SESSION_DURATION = 3600; // 1 hour
const size_t SSU_MAX_NUM_INTRODUCERS = 3;
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// payload types (4 bits)
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const uint8_t PAYLOAD_TYPE_SESSION_REQUEST = 0;
const uint8_t PAYLOAD_TYPE_SESSION_CREATED = 1;
const uint8_t PAYLOAD_TYPE_SESSION_CONFIRMED = 2;
const uint8_t PAYLOAD_TYPE_RELAY_REQUEST = 3;
const uint8_t PAYLOAD_TYPE_RELAY_RESPONSE = 4;
const uint8_t PAYLOAD_TYPE_RELAY_INTRO = 5;
const uint8_t PAYLOAD_TYPE_DATA = 6;
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const uint8_t PAYLOAD_TYPE_PEER_TEST = 7;
const uint8_t PAYLOAD_TYPE_SESSION_DESTROYED = 8;
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enum SessionState
{
eSessionStateUnknown,
eSessionStateIntroduced,
eSessionStateEstablished,
eSessionStateFailed
};
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class SSUServer;
class SSUSession: public TransportSession
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{
public:
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SSUSession (SSUServer& server, boost::asio::ip::udp::endpoint& remoteEndpoint,
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const i2p::data::RouterInfo * router = nullptr, bool peerTest = false);
void ProcessNextMessage (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint);
~SSUSession ();
void Connect ();
void Introduce (uint32_t iTag, const uint8_t * iKey);
void WaitForIntroduction ();
void Close ();
boost::asio::ip::udp::endpoint& GetRemoteEndpoint () { return m_RemoteEndpoint; };
void SendI2NPMessage (I2NPMessage * msg);
void SendPeerTest (); // Alice
SessionState GetState () const { return m_State; };
size_t GetNumSentBytes () const { return m_NumSentBytes; };
size_t GetNumReceivedBytes () const { return m_NumReceivedBytes; };
void SendKeepAlive ();
uint32_t GetRelayTag () const { return m_RelayTag; };
uint32_t GetCreationTime () const { return m_CreationTime; };
private:
void CreateAESandMacKey (const uint8_t * pubKey);
void PostI2NPMessage (I2NPMessage * msg);
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void ProcessMessage (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint); // call for established session
void ProcessSessionRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint);
void SendSessionRequest ();
void SendRelayRequest (uint32_t iTag, const uint8_t * iKey);
void ProcessSessionCreated (uint8_t * buf, size_t len);
void SendSessionCreated (const uint8_t * x);
void ProcessSessionConfirmed (uint8_t * buf, size_t len);
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void SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress);
void ProcessRelayRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& from);
void SendRelayResponse (uint32_t nonce, const boost::asio::ip::udp::endpoint& from,
const uint8_t * introKey, const boost::asio::ip::udp::endpoint& to);
void SendRelayIntro (SSUSession * session, const boost::asio::ip::udp::endpoint& from);
void ProcessRelayResponse (uint8_t * buf, size_t len);
void ProcessRelayIntro (uint8_t * buf, size_t len);
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void Established ();
void Failed ();
void ScheduleConnectTimer ();
void HandleConnectTimer (const boost::system::error_code& ecode);
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void ProcessPeerTest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint);
void SendPeerTest (uint32_t nonce, uint32_t address, uint16_t port, const uint8_t * introKey, bool toAddress = true);
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void ProcessData (uint8_t * buf, size_t len);
void SendSesionDestroyed ();
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void Send (uint8_t type, const uint8_t * payload, size_t len); // with session key
void Send (const uint8_t * buf, size_t size);
void FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len, const uint8_t * aesKey, const uint8_t * iv, const uint8_t * macKey);
void FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len); // with session key
void Decrypt (uint8_t * buf, size_t len, const uint8_t * aesKey);
void DecryptSessionKey (uint8_t * buf, size_t len);
bool Validate (uint8_t * buf, size_t len, const uint8_t * macKey);
const uint8_t * GetIntroKey () const;
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void ScheduleTermination ();
void HandleTerminationTimer (const boost::system::error_code& ecode);
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private:
friend class SSUData; // TODO: change in later
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SSUServer& m_Server;
boost::asio::ip::udp::endpoint m_RemoteEndpoint;
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boost::asio::deadline_timer m_Timer;
bool m_PeerTest;
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SessionState m_State;
bool m_IsSessionKey;
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uint32_t m_RelayTag;
std::set<uint32_t> m_PeerTestNonces;
i2p::crypto::CBCEncryption m_SessionKeyEncryption;
i2p::crypto::CBCDecryption m_SessionKeyDecryption;
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uint8_t m_SessionKey[32], m_MacKey[32];
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std::list<i2p::I2NPMessage *> m_DelayedMessages;
SSUData m_Data;
size_t m_NumSentBytes, m_NumReceivedBytes;
uint32_t m_CreationTime; // seconds since epoch
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};
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class SSUServer
{
public:
SSUServer (int port);
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~SSUServer ();
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void Start ();
void Stop ();
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SSUSession * GetSession (const i2p::data::RouterInfo * router, bool peerTest = false);
SSUSession * FindSession (const i2p::data::RouterInfo * router);
SSUSession * FindSession (const boost::asio::ip::udp::endpoint& e);
SSUSession * GetRandomEstablishedSession (const SSUSession * excluded);
void DeleteSession (SSUSession * session);
void DeleteAllSessions ();
boost::asio::io_service& GetService () { return m_Socket.get_io_service(); };
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);
SSUSession * FindRelaySession (uint32_t tag);
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private:
void Run ();
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void Receive ();
void HandleReceivedFrom (const boost::system::error_code& ecode, std::size_t bytes_transferred);
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template<typename Filter>
SSUSession * GetRandomSession (Filter filter);
std::set<SSUSession *> FindIntroducers (int maxNumIntroducers);
void ScheduleIntroducersUpdateTimer ();
void HandleIntroducersUpdateTimer (const boost::system::error_code& ecode);
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private:
bool m_IsRunning;
std::thread * m_Thread;
boost::asio::io_service m_Service;
boost::asio::io_service::work m_Work;
boost::asio::ip::udp::endpoint m_Endpoint;
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boost::asio::ip::udp::socket m_Socket;
boost::asio::ip::udp::endpoint m_SenderEndpoint;
boost::asio::deadline_timer m_IntroducersUpdateTimer;
std::list<boost::asio::ip::udp::endpoint> m_Introducers; // introducers we are connected to
uint8_t m_ReceiveBuffer[2*SSU_MTU];
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std::map<boost::asio::ip::udp::endpoint, SSUSession *> m_Sessions;
std::map<uint32_t, boost::asio::ip::udp::endpoint> m_Relays; // we are introducer
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public:
// for HTTP only
const decltype(m_Sessions)& GetSessions () const { return m_Sessions; };
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};
}
}
#endif