I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2013-2024, 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 STREAMING_H__
#define STREAMING_H__
#include <inttypes.h>
#include <string>
#include <unordered_map>
#include <set>
#include <queue>
#include <functional>
#include <memory>
#include <mutex>
#include <boost/asio.hpp>
#include "Base.h"
#include "I2PEndian.h"
#include "Identity.h"
#include "LeaseSet.h"
#include "I2NPProtocol.h"
#include "Garlic.h"
#include "Tunnel.h"
#include "util.h" // MemoryPool
namespace i2p
{
namespace client
{
class ClientDestination;
}
namespace stream
{
const uint16_t PACKET_FLAG_SYNCHRONIZE = 0x0001;
const uint16_t PACKET_FLAG_CLOSE = 0x0002;
const uint16_t PACKET_FLAG_RESET = 0x0004;
const uint16_t PACKET_FLAG_SIGNATURE_INCLUDED = 0x0008;
const uint16_t PACKET_FLAG_SIGNATURE_REQUESTED = 0x0010;
const uint16_t PACKET_FLAG_FROM_INCLUDED = 0x0020;
const uint16_t PACKET_FLAG_DELAY_REQUESTED = 0x0040;
const uint16_t PACKET_FLAG_MAX_PACKET_SIZE_INCLUDED = 0x0080;
const uint16_t PACKET_FLAG_PROFILE_INTERACTIVE = 0x0100;
const uint16_t PACKET_FLAG_ECHO = 0x0200;
const uint16_t PACKET_FLAG_NO_ACK = 0x0400;
const uint16_t PACKET_FLAG_OFFLINE_SIGNATURE = 0x0800;
const size_t STREAMING_MTU = 1730;
const size_t STREAMING_MTU_RATCHETS = 1812;
const size_t MAX_PACKET_SIZE = 4096;
const size_t COMPRESSION_THRESHOLD_SIZE = 66;
const int MAX_NUM_RESEND_ATTEMPTS = 6;
const int WINDOW_SIZE = 6; // in messages
const int MIN_WINDOW_SIZE = 1;
const int MAX_WINDOW_SIZE = 128;
const int WINDOW_SIZE_DROP_FRACTION = 10; // 1/10
const double RTT_EWMA_ALPHA = 0.5;
const int INITIAL_RTT = 8000; // in milliseconds
const int INITIAL_RTO = 9000; // in milliseconds
const int MIN_SEND_ACK_TIMEOUT = 2; // in milliseconds
const int SYN_TIMEOUT = 200; // how long we wait for SYN after follow-on, in milliseconds
const size_t MAX_PENDING_INCOMING_BACKLOG = 128;
const int PENDING_INCOMING_TIMEOUT = 10; // in seconds
const int MAX_RECEIVE_TIMEOUT = 20; // in seconds
struct Packet
{
size_t len, offset;
uint8_t buf[MAX_PACKET_SIZE];
uint64_t sendTime;
Packet (): len (0), offset (0), sendTime (0) {};
uint8_t * GetBuffer () { return buf + offset; };
size_t GetLength () const { return len - offset; };
uint32_t GetSendStreamID () const { return bufbe32toh (buf); };
uint32_t GetReceiveStreamID () const { return bufbe32toh (buf + 4); };
uint32_t GetSeqn () const { return bufbe32toh (buf + 8); };
uint32_t GetAckThrough () const { return bufbe32toh (buf + 12); };
uint8_t GetNACKCount () const { return buf[16]; };
uint32_t GetNACK (int i) const { return bufbe32toh (buf + 17 + 4 * i); };
const uint8_t * GetNACKs () const { return buf + 17; };
const uint8_t * GetOption () const { return buf + 17 + GetNACKCount ()*4 + 3; }; // 3 = resendDelay + flags
uint16_t GetFlags () const { return bufbe16toh (GetOption () - 2); };
uint16_t GetOptionSize () const { return bufbe16toh (GetOption ()); };
const uint8_t * GetOptionData () const { return GetOption () + 2; };
const uint8_t * GetPayload () const { return GetOptionData () + GetOptionSize (); };
bool IsSYN () const { return GetFlags () & PACKET_FLAG_SYNCHRONIZE; };
bool IsNoAck () const { return GetFlags () & PACKET_FLAG_NO_ACK; };
bool IsEcho () const { return GetFlags () & PACKET_FLAG_ECHO; };
};
struct PacketCmp
{
bool operator() (const Packet * p1, const Packet * p2) const
{
return p1->GetSeqn () < p2->GetSeqn ();
};
};
typedef std::function<void (const boost::system::error_code& ecode)> SendHandler;
struct SendBuffer
{
uint8_t * buf;
size_t len, offset;
SendHandler handler;
SendBuffer (const uint8_t * b, size_t l, SendHandler h):
len(l), offset (0), handler(h)
{
buf = new uint8_t[len];
memcpy (buf, b, len);
}
SendBuffer (size_t l): // create empty buffer
len(l), offset (0)
{
buf = new uint8_t[len];
}
~SendBuffer ()
{
delete[] buf;
if (handler) handler(boost::system::error_code ());
}
size_t GetRemainingSize () const { return len - offset; };
const uint8_t * GetRemaningBuffer () const { return buf + offset; };
void Cancel () { if (handler) handler (boost::asio::error::make_error_code (boost::asio::error::operation_aborted)); handler = nullptr; };
};
class SendBufferQueue
{
public:
SendBufferQueue (): m_Size (0) {};
~SendBufferQueue () { CleanUp (); };
void Add (std::shared_ptr<SendBuffer> buf);
size_t Get (uint8_t * buf, size_t len);
size_t GetSize () const { return m_Size; };
bool IsEmpty () const { return m_Buffers.empty (); };
void CleanUp ();
private:
std::list<std::shared_ptr<SendBuffer> > m_Buffers;
size_t m_Size;
};
enum StreamStatus
{
eStreamStatusNew = 0,
eStreamStatusOpen,
eStreamStatusReset,
eStreamStatusClosing,
eStreamStatusClosed,
eStreamStatusTerminated
};
class StreamingDestination;
class Stream: public std::enable_shared_from_this<Stream>
{
public:
Stream (boost::asio::io_service& service, StreamingDestination& local,
std::shared_ptr<const i2p::data::LeaseSet> remote, int port = 0); // outgoing
Stream (boost::asio::io_service& service, StreamingDestination& local); // incoming
~Stream ();
uint32_t GetSendStreamID () const { return m_SendStreamID; };
uint32_t GetRecvStreamID () const { return m_RecvStreamID; };
std::shared_ptr<const i2p::data::LeaseSet> GetRemoteLeaseSet () const { return m_RemoteLeaseSet; };
std::shared_ptr<const i2p::data::IdentityEx> GetRemoteIdentity () const { return m_RemoteIdentity; };
bool IsOpen () const { return m_Status == eStreamStatusOpen; };
bool IsEstablished () const { return m_SendStreamID; };
StreamStatus GetStatus () const { return m_Status; };
StreamingDestination& GetLocalDestination () { return m_LocalDestination; };
void HandleNextPacket (Packet * packet);
void HandlePing (Packet * packet);
size_t Send (const uint8_t * buf, size_t len);
void AsyncSend (const uint8_t * buf, size_t len, SendHandler handler);
void SendPing ();
template<typename Buffer, typename ReceiveHandler>
void AsyncReceive (const Buffer& buffer, ReceiveHandler handler, int timeout = 0);
size_t ReadSome (uint8_t * buf, size_t len) { return ConcatenatePackets (buf, len); };
size_t Receive (uint8_t * buf, size_t len, int timeout);
void AsyncClose() { m_Service.post(std::bind(&Stream::Close, shared_from_this())); };
/** only call close from destination thread, use Stream::AsyncClose for other threads */
void Close ();
void Cancel () { m_ReceiveTimer.cancel (); };
size_t GetNumSentBytes () const { return m_NumSentBytes; };
size_t GetNumReceivedBytes () const { return m_NumReceivedBytes; };
size_t GetSendQueueSize () const { return m_SentPackets.size (); };
size_t GetReceiveQueueSize () const { return m_ReceiveQueue.size (); };
size_t GetSendBufferSize () const { return m_SendBuffer.GetSize (); };
int GetWindowSize () const { return m_WindowSize; };
int GetRTT () const { return m_RTT; };
void Terminate (bool deleteFromDestination = true);
private:
void CleanUp ();
void SendBuffer ();
void SendQuickAck ();
void SendClose ();
bool SendPacket (Packet * packet);
void SendPackets (const std::vector<Packet *>& packets);
void SendUpdatedLeaseSet ();
void SavePacket (Packet * packet);
void ProcessPacket (Packet * packet);
bool ProcessOptions (uint16_t flags, Packet * packet);
void ProcessAck (Packet * packet);
size_t ConcatenatePackets (uint8_t * buf, size_t len);
void UpdateCurrentRemoteLease (bool expired = false);
template<typename Buffer, typename ReceiveHandler>
void HandleReceiveTimer (const boost::system::error_code& ecode, const Buffer& buffer, ReceiveHandler handler, int remainingTimeout);
void ScheduleResend ();
void HandleResendTimer (const boost::system::error_code& ecode);
void ScheduleAck (int timeout);
void HandleAckSendTimer (const boost::system::error_code& ecode);
private:
boost::asio::io_service& m_Service;
uint32_t m_SendStreamID, m_RecvStreamID, m_SequenceNumber;
int32_t m_LastReceivedSequenceNumber;
StreamStatus m_Status;
bool m_IsAckSendScheduled;
StreamingDestination& m_LocalDestination;
std::shared_ptr<const i2p::data::IdentityEx> m_RemoteIdentity;
std::shared_ptr<const i2p::crypto::Verifier> m_TransientVerifier; // in case of offline key
std::shared_ptr<const i2p::data::LeaseSet> m_RemoteLeaseSet;
std::shared_ptr<i2p::garlic::GarlicRoutingSession> m_RoutingSession;
std::shared_ptr<const i2p::data::Lease> m_CurrentRemoteLease;
std::shared_ptr<i2p::tunnel::OutboundTunnel> m_CurrentOutboundTunnel;
std::queue<Packet *> m_ReceiveQueue;
std::set<Packet *, PacketCmp> m_SavedPackets;
std::set<Packet *, PacketCmp> m_SentPackets;
boost::asio::deadline_timer m_ReceiveTimer, m_ResendTimer, m_AckSendTimer;
size_t m_NumSentBytes, m_NumReceivedBytes;
uint16_t m_Port;
SendBufferQueue m_SendBuffer;
int m_WindowSize, m_RTT, m_RTO, m_AckDelay;
uint64_t m_LastWindowSizeIncreaseTime;
int m_NumResendAttempts;
size_t m_MTU;
};
class StreamingDestination: public std::enable_shared_from_this<StreamingDestination>
{
public:
typedef std::function<void (std::shared_ptr<Stream>)> Acceptor;
StreamingDestination (std::shared_ptr<i2p::client::ClientDestination> owner, uint16_t localPort = 0, bool gzip = false);
~StreamingDestination ();
void Start ();
void Stop ();
std::shared_ptr<Stream> CreateNewOutgoingStream (std::shared_ptr<const i2p::data::LeaseSet> remote, int port = 0);
void SendPing (std::shared_ptr<const i2p::data::LeaseSet> remote);
void DeleteStream (std::shared_ptr<Stream> stream);
bool DeleteStream (uint32_t recvStreamID);
void SetAcceptor (const Acceptor& acceptor);
void ResetAcceptor ();
bool IsAcceptorSet () const { return m_Acceptor != nullptr; };
void AcceptOnce (const Acceptor& acceptor);
void AcceptOnceAcceptor (std::shared_ptr<Stream> stream, Acceptor acceptor, Acceptor prev);
std::shared_ptr<Stream> AcceptStream (int timeout = 0); // sync
std::shared_ptr<i2p::client::ClientDestination> GetOwner () const { return m_Owner; };
void SetOwner (std::shared_ptr<i2p::client::ClientDestination> owner) { m_Owner = owner; };
uint16_t GetLocalPort () const { return m_LocalPort; };
void HandleDataMessagePayload (const uint8_t * buf, size_t len);
std::shared_ptr<I2NPMessage> CreateDataMessage (const uint8_t * payload, size_t len, uint16_t toPort, bool checksum = true, bool gzip = false);
Packet * NewPacket () { return m_PacketsPool.Acquire(); }
void DeletePacket (Packet * p) { return m_PacketsPool.Release(p); }
private:
void HandleNextPacket (Packet * packet);
std::shared_ptr<Stream> CreateNewIncomingStream (uint32_t receiveStreamID);
void HandlePendingIncomingTimer (const boost::system::error_code& ecode);
private:
std::shared_ptr<i2p::client::ClientDestination> m_Owner;
uint16_t m_LocalPort;
bool m_Gzip; // gzip compression of data messages
std::mutex m_StreamsMutex;
std::unordered_map<uint32_t, std::shared_ptr<Stream> > m_Streams; // sendStreamID->stream
std::unordered_map<uint32_t, std::shared_ptr<Stream> > m_IncomingStreams; // receiveStreamID->stream
std::shared_ptr<Stream> m_LastStream;
Acceptor m_Acceptor;
std::list<std::shared_ptr<Stream> > m_PendingIncomingStreams;
boost::asio::deadline_timer m_PendingIncomingTimer;
std::unordered_map<uint32_t, std::list<Packet *> > m_SavedPackets; // receiveStreamID->packets, arrived before SYN
i2p::util::MemoryPool<Packet> m_PacketsPool;
i2p::util::MemoryPool<I2NPMessageBuffer<I2NP_MAX_SHORT_MESSAGE_SIZE> > m_I2NPMsgsPool;
public:
i2p::data::GzipInflator m_Inflator;
i2p::data::GzipDeflator m_Deflator;
// for HTTP only
const decltype(m_Streams)& GetStreams () const { return m_Streams; };
};
//-------------------------------------------------
template<typename Buffer, typename ReceiveHandler>
void Stream::AsyncReceive (const Buffer& buffer, ReceiveHandler handler, int timeout)
{
auto s = shared_from_this();
m_Service.post ([s, buffer, handler, timeout](void)
{
if (!s->m_ReceiveQueue.empty () || s->m_Status == eStreamStatusReset)
s->HandleReceiveTimer (boost::asio::error::make_error_code (boost::asio::error::operation_aborted), buffer, handler, 0);
else
{
int t = (timeout > MAX_RECEIVE_TIMEOUT) ? MAX_RECEIVE_TIMEOUT : timeout;
s->m_ReceiveTimer.expires_from_now (boost::posix_time::seconds(t));
int left = timeout - t;
s->m_ReceiveTimer.async_wait (
[s, buffer, handler, left](const boost::system::error_code & ec)
{
s->HandleReceiveTimer(ec, buffer, handler, left);
});
}
});
}
template<typename Buffer, typename ReceiveHandler>
void Stream::HandleReceiveTimer (const boost::system::error_code& ecode, const Buffer& buffer, ReceiveHandler handler, int remainingTimeout)
{
size_t received = ConcatenatePackets (boost::asio::buffer_cast<uint8_t *>(buffer), boost::asio::buffer_size(buffer));
if (received > 0)
handler (boost::system::error_code (), received);
else if (ecode == boost::asio::error::operation_aborted)
{
// timeout not expired
if (m_Status == eStreamStatusReset)
handler (boost::asio::error::make_error_code (boost::asio::error::connection_reset), 0);
else
handler (boost::asio::error::make_error_code (boost::asio::error::operation_aborted), 0);
}
else
{
// timeout expired
if (remainingTimeout <= 0)
handler (boost::asio::error::make_error_code (boost::asio::error::timed_out), received);
else
{
// itermediate interrupt
SendUpdatedLeaseSet (); // send our leaseset if applicable
AsyncReceive (buffer, handler, remainingTimeout);
}
}
}
}
}
#endif