I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2022-2024, 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 <unordered_map>
#include <unordered_set>
#include <vector>
#include <mutex>
#include <random>
#include "util.h"
#include "SSU2Session.h"
#include "Socks5.h"
namespace i2p
{
namespace transport
{
const int SSU2_TERMINATION_CHECK_TIMEOUT = 23; // in seconds
const int SSU2_TERMINATION_CHECK_TIMEOUT_VARIANCE = 5; // in seconds
const int SSU2_CLEANUP_INTERVAL = 72; // in seconds
const int SSU2_RESEND_CHECK_TIMEOUT = 40; // in milliseconds
const int SSU2_RESEND_CHECK_TIMEOUT_VARIANCE = 10; // in milliseconds
const int SSU2_RESEND_CHECK_MORE_TIMEOUT = 4; // in milliseconds
const int SSU2_RESEND_CHECK_MORE_TIMEOUT_VARIANCE = 9; // in milliseconds
const size_t SSU2_MAX_RESEND_PACKETS = 128; // packets to resend at the time
const uint64_t SSU2_SOCKET_MIN_BUFFER_SIZE = 128 * 1024;
const uint64_t SSU2_SOCKET_MAX_BUFFER_SIZE = 4 * 1024 * 1024;
const size_t SSU2_MAX_NUM_INTRODUCERS = 3;
const size_t SSU2_MIN_RECEIVED_PACKET_SIZE = 40; // 16 byte short header + 8 byte minimum payload + 16 byte MAC
const int SSU2_TO_INTRODUCER_SESSION_DURATION = 3600; // 1 hour
const int SSU2_TO_INTRODUCER_SESSION_EXPIRATION = 4800; // 80 minutes
const int SSU2_KEEP_ALIVE_INTERVAL = 15; // in seconds
const int SSU2_KEEP_ALIVE_INTERVAL_VARIANCE = 4; // in seconds
const int SSU2_PROXY_CONNECT_RETRY_TIMEOUT = 30; // in seconds
const int SSU2_HOLE_PUNCH_EXPIRATION = 20; // in seconds
class SSU2Server: private i2p::util::RunnableServiceWithWork
{
struct Packet
{
uint8_t buf[SSU2_MAX_PACKET_SIZE];
size_t len;
boost::asio::ip::udp::endpoint from;
};
class ReceiveService: public i2p::util::RunnableService
{
public:
ReceiveService (const std::string& name): RunnableService (name) {};
boost::asio::io_service& GetService () { return GetIOService (); };
void Start () { StartIOService (); };
void Stop () { StopIOService (); };
};
public:
SSU2Server ();
~SSU2Server () {};
void Start ();
void Stop ();
boost::asio::io_service& GetService () { return GetIOService (); };
void SetLocalAddress (const boost::asio::ip::address& localAddress);
bool SetProxy (const std::string& address, uint16_t port);
bool UsesProxy () const { return m_IsThroughProxy; };
bool IsSupported (const boost::asio::ip::address& addr) const;
uint16_t GetPort (bool v4) const;
bool IsConnectedRecently (const boost::asio::ip::udp::endpoint& ep) const;
void AddConnectedRecently (const boost::asio::ip::udp::endpoint& ep, uint64_t ts);
std::mt19937& GetRng () { return m_Rng; }
bool IsMaxNumIntroducers (bool v4) const { return (v4 ? m_Introducers.size () : m_IntroducersV6.size ()) >= SSU2_MAX_NUM_INTRODUCERS; }
bool IsSyncClockFromPeers () const { return m_IsSyncClockFromPeers; };
void AdjustTimeOffset (int64_t offset, std::shared_ptr<const i2p::data::IdentityEx> from);
void AddSession (std::shared_ptr<SSU2Session> session);
void RemoveSession (uint64_t connID);
void AddSessionByRouterHash (std::shared_ptr<SSU2Session> session);
bool AddPendingOutgoingSession (std::shared_ptr<SSU2Session> session);
void RemovePendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep);
std::shared_ptr<SSU2Session> FindSession (const i2p::data::IdentHash& ident) const;
std::shared_ptr<SSU2Session> FindPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep) const;
std::shared_ptr<SSU2Session> GetRandomPeerTestSession (i2p::data::RouterInfo::CompatibleTransports remoteTransports,
const i2p::data::IdentHash& excluded);
void AddRelay (uint32_t tag, std::shared_ptr<SSU2Session> relay);
void RemoveRelay (uint32_t tag);
std::shared_ptr<SSU2Session> FindRelaySession (uint32_t tag);
void Send (const uint8_t * header, size_t headerLen, const uint8_t * payload, size_t payloadLen,
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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, bool peerTest = false);
bool StartPeerTest (std::shared_ptr<const i2p::data::RouterInfo> router, bool v4);
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);
uint64_t GetIncomingToken (const boost::asio::ip::udp::endpoint& ep);
std::pair<uint64_t, uint32_t> NewIncomingToken (const boost::asio::ip::udp::endpoint& ep);
void RescheduleIntroducersUpdateTimer ();
void RescheduleIntroducersUpdateTimerV6 ();
i2p::util::MemoryPool<SSU2SentPacket>& GetSentPacketsPool () { return m_SentPacketsPool; };
i2p::util::MemoryPool<SSU2IncompleteMessage>& GetIncompleteMessagesPool () { return m_IncompleteMessagesPool; };
i2p::util::MemoryPool<SSU2IncompleteMessage::Fragment>& GetFragmentsPool () { return m_FragmentsPool; };
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 HandleReceivedPacket (Packet * packet);
void HandleReceivedPackets (std::vector<Packet *> packets);
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);
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void ScheduleCleanup ();
void HandleCleanupTimer (const boost::system::error_code& ecode);
void ScheduleResend (bool more);
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void HandleResendTimer (const boost::system::error_code& ecode);
void ConnectThroughIntroducer (std::shared_ptr<SSU2Session> session);
std::vector<std::shared_ptr<SSU2Session> > FindIntroducers (int maxNumIntroducers,
bool v4, const std::unordered_set<i2p::data::IdentHash>& excluded) const;
void UpdateIntroducers (bool v4);
void ScheduleIntroducersUpdateTimer ();
void HandleIntroducersUpdateTimer (const boost::system::error_code& ecode, bool v4);
void ScheduleIntroducersUpdateTimerV6 ();
void SendThroughProxy (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);
void ProcessNextPacketFromProxy (uint8_t * buf, size_t len);
void ConnectToProxy ();
void ReconnectToProxy ();
void HandshakeWithProxy ();
void ReadHandshakeWithProxyReply ();
void SendUDPAssociateRequest ();
void ReadUDPAssociateReply ();
void ReadUDPAssociateSocket (); // handle if closed by peer
private:
ReceiveService m_ReceiveService;
boost::asio::ip::udp::socket m_SocketV4, m_SocketV6;
boost::asio::ip::address m_AddressV4, m_AddressV6;
std::unordered_map<uint64_t, std::shared_ptr<SSU2Session> > m_Sessions;
std::unordered_map<i2p::data::IdentHash, std::shared_ptr<SSU2Session> > m_SessionsByRouterHash;
std::map<boost::asio::ip::udp::endpoint, std::shared_ptr<SSU2Session> > m_PendingOutgoingSessions;
mutable std::mutex m_PendingOutgoingSessionsMutex;
std::map<boost::asio::ip::udp::endpoint, std::pair<uint64_t, uint32_t> > m_IncomingTokens, m_OutgoingTokens; // remote endpoint -> (token, expires in seconds)
std::unordered_map<uint32_t, std::shared_ptr<SSU2Session> > m_Relays; // we are introducer, relay tag -> session
std::list<i2p::data::IdentHash> m_Introducers, m_IntroducersV6; // introducers we are connected to
i2p::util::MemoryPoolMt<Packet> m_PacketsPool;
i2p::util::MemoryPool<SSU2SentPacket> m_SentPacketsPool;
i2p::util::MemoryPool<SSU2IncompleteMessage> m_IncompleteMessagesPool;
i2p::util::MemoryPool<SSU2IncompleteMessage::Fragment> m_FragmentsPool;
boost::asio::deadline_timer m_TerminationTimer, m_CleanupTimer, m_ResendTimer,
m_IntroducersUpdateTimer, m_IntroducersUpdateTimerV6;
std::shared_ptr<SSU2Session> m_LastSession;
bool m_IsPublished; // if we maintain introducers
bool m_IsSyncClockFromPeers;
int64_t m_PendingTimeOffset; // during peer test
std::shared_ptr<const i2p::data::IdentityEx> m_PendingTimeOffsetFrom;
std::mt19937 m_Rng;
std::map<boost::asio::ip::udp::endpoint, uint64_t> m_ConnectedRecently; // endpoint -> last activity time in seconds
// proxy
bool m_IsThroughProxy;
uint8_t m_UDPRequestHeader[SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE];
std::unique_ptr<boost::asio::ip::tcp::endpoint> m_ProxyEndpoint;
std::unique_ptr<boost::asio::ip::tcp::socket> m_UDPAssociateSocket;
std::unique_ptr<boost::asio::ip::udp::endpoint> m_ProxyRelayEndpoint;
std::unique_ptr<boost::asio::deadline_timer> m_ProxyConnectRetryTimer;
public:
// for HTTP/I2PControl
const decltype(m_Sessions)& GetSSU2Sessions () const { return m_Sessions; };
};
}
}
#endif