I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#ifndef STREAMING_H__
#define STREAMING_H__
#include <inttypes.h>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <functional>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include "I2PEndian.h"
#include "Identity.h"
#include "LeaseSet.h"
#include "I2NPProtocol.h"
#include "Garlic.h"
#include "Tunnel.h"
namespace i2p
{
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 size_t STREAMING_MTU = 1730;
const size_t MAX_PACKET_SIZE = 4096;
const size_t COMPRESSION_THRESHOLD_SIZE = 66;
const int RESEND_TIMEOUT = 10; // in seconds
const int MAX_NUM_RESEND_ATTEMPTS = 5;
struct Packet
{
uint8_t buf[MAX_PACKET_SIZE];
size_t len, offset;
int numResendAttempts;
Packet (): len (0), offset (0), numResendAttempts (0) {};
uint8_t * GetBuffer () { return buf + offset; };
size_t GetLength () const { return len - offset; };
uint32_t GetSendStreamID () const { return be32toh (*(uint32_t *)buf); };
uint32_t GetReceiveStreamID () const { return be32toh (*(uint32_t *)(buf + 4)); };
uint32_t GetSeqn () const { return be32toh (*(uint32_t *)(buf + 8)); };
uint32_t GetAckThrough () const { return be32toh (*(uint32_t *)(buf + 12)); };
uint8_t GetNACKCount () const { return buf[16]; };
uint32_t GetNACK (int i) const { return be32toh (((uint32_t *)(buf + 17))[i]); };
const uint8_t * GetOption () const { return buf + 17 + GetNACKCount ()*4 + 3; }; // 3 = resendDelay + flags
uint16_t GetFlags () const { return be16toh (*(uint16_t *)(GetOption () - 2)); };
uint16_t GetOptionSize () const { return be16toh (*(uint16_t *)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; };
};
struct PacketCmp
{
bool operator() (const Packet * p1, const Packet * p2) const
{
return p1->GetSeqn () < p2->GetSeqn ();
};
};
class StreamingDestination;
class Stream
{
public:
Stream (boost::asio::io_service& service, StreamingDestination * local, const i2p::data::LeaseSet& remote); // 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; };
const i2p::data::LeaseSet * GetRemoteLeaseSet () const { return m_RemoteLeaseSet; };
const i2p::data::IdentityEx& GetRemoteIdentity () const { return m_RemoteIdentity; };
bool IsOpen () const { return m_IsOpen; };
bool IsEstablished () const { return m_SendStreamID; };
StreamingDestination * GetLocalDestination () { return m_LocalDestination; };
void HandleNextPacket (Packet * packet);
size_t Send (const uint8_t * buf, size_t len);
template<typename Buffer, typename ReceiveHandler>
void AsyncReceive (const Buffer& buffer, ReceiveHandler handler, int timeout = 0);
void Close ();
void SetLeaseSetUpdated () { m_LeaseSetUpdated = true; };
private:
void SendQuickAck ();
bool SendPacket (Packet * packet);
void SendPackets (const std::vector<Packet *>& packets);
void SavePacket (Packet * packet);
void ProcessPacket (Packet * packet);
void ProcessAck (Packet * packet);
size_t ConcatenatePackets (uint8_t * buf, size_t len);
void UpdateCurrentRemoteLease ();
template<typename Buffer, typename ReceiveHandler>
void HandleReceiveTimer (const boost::system::error_code& ecode, const Buffer& buffer, ReceiveHandler handler);
void ScheduleResend ();
void HandleResendTimer (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;
bool m_IsOpen, m_LeaseSetUpdated;
StreamingDestination * m_LocalDestination;
i2p::data::IdentityEx m_RemoteIdentity;
const i2p::data::LeaseSet * m_RemoteLeaseSet;
i2p::garlic::GarlicRoutingSession * m_RoutingSession;
i2p::data::Lease m_CurrentRemoteLease;
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;
};
//-------------------------------------------------
template<typename Buffer, typename ReceiveHandler>
void Stream::AsyncReceive (const Buffer& buffer, ReceiveHandler handler, int timeout)
{
if (!m_ReceiveQueue.empty ())
{
size_t received = ConcatenatePackets (boost::asio::buffer_cast<uint8_t *>(buffer), boost::asio::buffer_size(buffer));
if (received)
{
// TODO: post to stream's thread
handler (boost::system::error_code (), received);
return;
}
}
if (!m_IsOpen)
{
handler (boost::asio::error::make_error_code (boost::asio::error::connection_reset), 0);
return;
}
m_ReceiveTimer.expires_from_now (boost::posix_time::seconds(timeout));
m_ReceiveTimer.async_wait ([=](const boost::system::error_code& ecode)
{ this->HandleReceiveTimer (ecode, buffer, handler); });
}
template<typename Buffer, typename ReceiveHandler>
void Stream::HandleReceiveTimer (const boost::system::error_code& ecode, const Buffer& buffer, ReceiveHandler handler)
{
size_t received = ConcatenatePackets (boost::asio::buffer_cast<uint8_t *>(buffer), boost::asio::buffer_size(buffer));
if (ecode == boost::asio::error::operation_aborted)
{
// timeout not expired
if (m_IsOpen)
// no error
handler (boost::system::error_code (), received);
else
// socket closed
handler (boost::asio::error::make_error_code (boost::asio::error::operation_aborted), 0);
}
else
// timeout expired
handler (boost::asio::error::make_error_code (boost::asio::error::timed_out), received);
}
}
}
#endif