I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* 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 <map>
#include <unordered_map>
#include <boost/asio.hpp>
#include "Crypto.h"
#include "RouterInfo.h"
#include "TransportSession.h"
namespace i2p
{
namespace transport
{
const int SSU2_CONNECT_TIMEOUT = 5; // 5 seconds
const int SSU2_TERMINATION_TIMEOUT = 330; // 5.5 minutes
const int SSU2_TERMINATION_CHECK_TIMEOUT = 30; // 30 seconds
const int SSU2_TOKEN_EXPIRATION_TIMEOUT = 9; // in second
const size_t SSU2_SOCKET_RECEIVE_BUFFER_SIZE = 0x1FFFF; // 128K
const size_t SSU2_SOCKET_SEND_BUFFER_SIZE = 0x1FFFF; // 128K
const size_t SSU2_MTU = 1488;
enum SSU2MessageType
{
eSSU2SessionRequest = 0,
eSSU2SessionCreated = 1,
eSSU2SessionConfirmed = 2,
eSSU2Data = 6,
eSSU2Retry = 9,
eSSU2TokenRequest = 10
};
enum SSU2BlockType
{
eSSU2BlkDateTime = 0,
eSSU2BlkOptions, // 1
eSSU2BlkRouterInfo, // 2
eSSU2BlkI2NPMessage, // 3
eSSU2BlkFirstFragment, // 4
eSSU2BlkFollowOnFragment, // 5
eSSU2BlkTermination, // 6
eSSU2BlkRelayRequest, // 7
eSSU2BlkRelayResponse, // 8
eSSU2BlkRelayIntro, // 9
eSSU2BlkPeerTest, // 10
eSSU2BlkNextNonce, // 11
eSSU2BlkAck, // 12
eSSU2BlkAddress, // 13
eSSU2BlkIntroKey, // 14
eSSU2BlkRelayTagRequest, // 15
eSSU2BlkRelayTag, // 16
eSSU2BlkNewToken, // 17
eSSU2BlkPathChallenge, // 18
eSSU2BlkPathResponse, // 19
eSSU2BlkFirstPacketNumber, // 20
eSSU2BlkPadding = 254
};
enum SSU2SessionState
{
eSSU2SessionStateUnknown,
eSSU2SessionStateEstablished,
eSSU2SessionStateClosed,
eSSU2SessionStateFailed
};
// RouterInfo flags
const uint8_t SSU2_ROUTER_INFO_FLAG_REQUEST_FLOOD = 0x01;
const uint8_t SSU2_ROUTER_INFO_FLAG_GZIP = 0x02;
class SSU2Server;
class SSU2Session: public TransportSession, public std::enable_shared_from_this<SSU2Session>
{
union Header
{
uint64_t ll[2];
uint8_t buf[16];
struct
{
uint64_t connID;
uint32_t packetNum;
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 ();
void SetRemoteEndpoint (const boost::asio::ip::udp::endpoint& ep) { m_RemoteEndpoint = ep; };
void Connect ();
void Established ();
void Done () override {};
void SendI2NPMessages (const std::vector<std::shared_ptr<I2NPMessage> >& msgs) override {};
bool IsEstablished () const { return m_State == eSSU2SessionStateEstablished; };
void ProcessFirstIncomingMessage (uint64_t connID, uint8_t * buf, size_t len);
bool ProcessSessionCreated (uint8_t * buf, size_t len);
bool ProcessSessionConfirmed (uint8_t * buf, size_t len);
bool ProcessRetry (uint8_t * buf, size_t len);
void ProcessData (uint8_t * buf, size_t len);
private:
void ProcessSessionRequest (Header& header, uint8_t * buf, size_t len);
void ProcessTokenRequest (Header& header, uint8_t * buf, size_t len);
void SendSessionRequest (uint64_t token = 0);
void SendSessionCreated (const uint8_t * X);
void SendSessionConfirmed (const uint8_t * Y);
void KDFDataPhase (uint8_t * keydata_ab, uint8_t * keydata_ba);
void SendTokenRequest ();
void SendRetry ();
void SendData (const uint8_t * buf, size_t len);
void SendQuickAck ();
void HandlePayload (const uint8_t * buf, size_t len);
bool ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep);
std::shared_ptr<const i2p::data::RouterInfo> ExtractRouterInfo (const uint8_t * buf, size_t size);
void CreateNonce (uint64_t seqn, uint8_t * nonce);
size_t CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len);
size_t CreateAckBlock (uint8_t * buf, size_t len);
size_t CreatePaddingBlock (uint8_t * buf, size_t len);
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;
boost::asio::ip::udp::endpoint m_RemoteEndpoint;
uint64_t m_DestConnID, m_SourceConnID;
SSU2SessionState m_State;
uint8_t m_KeyDataSend[64], m_KeyDataReceive[64];
uint32_t m_SendPacketNum, m_ReceivePacketNum;
i2p::I2NPMessagesHandler m_Handler;
};
class SSU2Server: private i2p::util::RunnableServiceWithWork
{
struct Packet
{
uint8_t buf[SSU2_MTU];
size_t len;
boost::asio::ip::udp::endpoint from;
};
public:
SSU2Server ();
~SSU2Server () {};
void Start ();
void Stop ();
boost::asio::io_service& GetService () { return GetIOService (); };
void AddSession (uint64_t connID, std::shared_ptr<SSU2Session> session);
void AddPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep, std::shared_ptr<SSU2Session> session);
void Send (const uint8_t * header, size_t headerLen, const uint8_t * payload, size_t payloadLen,
const boost::asio::ip::udp::endpoint& to);
void Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen,
const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to);
bool CreateSession (std::shared_ptr<const i2p::data::RouterInfo> router,
std::shared_ptr<const i2p::data::RouterInfo::Address> address);
void UpdateOutgoingToken (const boost::asio::ip::udp::endpoint& ep, uint64_t token, uint32_t exp);
uint64_t FindOutgoingToken (const boost::asio::ip::udp::endpoint& ep) const;
uint64_t GetIncomingToken (const boost::asio::ip::udp::endpoint& ep);
private:
boost::asio::ip::udp::socket& OpenSocket (const boost::asio::ip::udp::endpoint& localEndpoint);
void Receive (boost::asio::ip::udp::socket& socket);
void HandleReceivedFrom (const boost::system::error_code& ecode, size_t bytes_transferred,
Packet * packet, boost::asio::ip::udp::socket& socket);
void ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint);
void ScheduleTermination ();
void HandleTerminationTimer (const boost::system::error_code& ecode);
private:
boost::asio::ip::udp::socket m_Socket, m_SocketV6;
std::unordered_map<uint64_t, std::shared_ptr<SSU2Session> > m_Sessions;
std::map<boost::asio::ip::udp::endpoint, std::shared_ptr<SSU2Session> > m_PendingOutgoingSessions;
std::map<boost::asio::ip::udp::endpoint, std::pair<uint64_t, uint32_t> > m_IncomingTokens, m_OutgoingTokens; // remote endpoint -> (token, expires in seconds)
i2p::util::MemoryPoolMt<Packet> m_PacketsPool;
boost::asio::deadline_timer m_TerminationTimer;
};
}
}
#endif