PurpleI2P
/
i2pd
mirror of https://github.com/PurpleI2P/i2pd.git
1
0
Fork 0
Code Issues Releases Activity
Browse Source

improved congestion control

pull/2076/head
orignal 5 months ago
parent
ff8941af71
commit
199d149bed
2 changed files with 154 additions and 43 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 172
      libi2pd/Streaming.cpp
  2. 23
      libi2pd/Streaming.h

172
libi2pd/Streaming.cpp
Unescape View File

@ -69,13 +69,14 @@ namespace stream @@ -69,13 +69,14 @@ namespace stream
Stream::Stream (boost::asio::io_service& service, StreamingDestination& local,
std::shared_ptr<const i2p::data::LeaseSet> remote, int port): m_Service (service),
m_SendStreamID (0), m_SequenceNumber (0),
m_TunnelsChangeSequenceNumber (0), m_LastReceivedSequenceNumber (-1),
m_Status (eStreamStatusNew), m_IsAckSendScheduled (false), m_LocalDestination (local),
m_RemoteLeaseSet (remote), m_ReceiveTimer (m_Service), m_ResendTimer (m_Service),
m_TunnelsChangeSequenceNumber (0), m_LastReceivedSequenceNumber (-1), m_PreviousReceivedSequenceNumber (-1),
m_Status (eStreamStatusNew), m_IsAckSendScheduled (false), m_IsNAcked (false), m_IsWinDropped (true),
m_IsTimeOutResend (false), m_LocalDestination (local),
m_RemoteLeaseSet (remote), m_ReceiveTimer (m_Service), m_SendTimer (m_Service), m_ResendTimer (m_Service),
m_AckSendTimer (m_Service), m_NumSentBytes (0), m_NumReceivedBytes (0), m_Port (port),
m_RTT (INITIAL_RTT), m_WindowSize (MIN_WINDOW_SIZE), m_RTO (INITIAL_RTO),
m_AckDelay (local.GetOwner ()->GetStreamingAckDelay ()),
m_LastWindowSizeIncreaseTime (0), m_NumResendAttempts (0), m_MTU (STREAMING_MTU)
m_RTT (INITIAL_RTT), m_WindowSize (INITIAL_WINDOW_SIZE), m_RTO (INITIAL_RTO),
m_AckDelay (local.GetOwner ()->GetStreamingAckDelay ()), m_PrewRTTSample (INITIAL_RTT), m_PrewRTT (INITIAL_RTT), m_Jitter (0),
m_LastWindowSizeIncreaseTime (0), m_PacingTime (INITIAL_PACING_TIME), m_NumResendAttempts (0), m_MTU (STREAMING_MTU)
{
RAND_bytes ((uint8_t *)&m_RecvStreamID, 4);
m_RemoteIdentity = remote->GetIdentity ();
@ -83,12 +84,14 @@ namespace stream @@ -83,12 +84,14 @@ namespace stream
Stream::Stream (boost::asio::io_service& service, StreamingDestination& local):
m_Service (service), m_SendStreamID (0), m_SequenceNumber (0),
m_TunnelsChangeSequenceNumber (0), m_LastReceivedSequenceNumber (-1),
m_Status (eStreamStatusNew), m_IsAckSendScheduled (false), m_LocalDestination (local),
m_ReceiveTimer (m_Service), m_ResendTimer (m_Service), m_AckSendTimer (m_Service),
m_TunnelsChangeSequenceNumber (0), m_LastReceivedSequenceNumber (-1), m_PreviousReceivedSequenceNumber (-1),
m_Status (eStreamStatusNew), m_IsAckSendScheduled (false), m_IsNAcked (false), m_IsWinDropped (true),
m_IsTimeOutResend (false), m_LocalDestination (local),
m_ReceiveTimer (m_Service), m_SendTimer (m_Service), m_ResendTimer (m_Service), m_AckSendTimer (m_Service),
m_NumSentBytes (0), m_NumReceivedBytes (0), m_Port (0), m_RTT (INITIAL_RTT),
m_WindowSize (MIN_WINDOW_SIZE), m_RTO (INITIAL_RTO), m_AckDelay (local.GetOwner ()->GetStreamingAckDelay ()),
m_LastWindowSizeIncreaseTime (0), m_NumResendAttempts (0), m_MTU (STREAMING_MTU)
m_WindowSize (INITIAL_WINDOW_SIZE), m_RTO (INITIAL_RTO), m_AckDelay (local.GetOwner ()->GetStreamingAckDelay ()),
m_PrewRTTSample (INITIAL_RTT), m_PrewRTT (INITIAL_RTT), m_Jitter (0),
m_LastWindowSizeIncreaseTime (0), m_PacingTime (INITIAL_PACING_TIME), m_NumResendAttempts (0), m_MTU (STREAMING_MTU)
{
RAND_bytes ((uint8_t *)&m_RecvStreamID, 4);
}
@ -203,6 +206,12 @@ namespace stream @@ -203,6 +206,12 @@ namespace stream
{
// we have received duplicate
LogPrint (eLogWarning, "Streaming: Duplicate message ", receivedSeqn, " on sSID=", m_SendStreamID);
if (receivedSeqn <= m_PreviousReceivedSequenceNumber || receivedSeqn == m_LastReceivedSequenceNumber)
{
m_CurrentOutboundTunnel = m_LocalDestination.GetOwner ()->GetTunnelPool ()->GetNextOutboundTunnel (m_CurrentOutboundTunnel);
UpdateCurrentRemoteLease ();
}
m_PreviousReceivedSequenceNumber = receivedSeqn;
SendQuickAck (); // resend ack for previous message again
m_LocalDestination.DeletePacket (packet); // packet dropped
}
@ -410,6 +419,7 @@ namespace stream @@ -410,6 +419,7 @@ namespace stream
}
int rttSample = INT_MAX;
bool firstRttSample = false;
m_IsNAcked = false;
int nackCount = packet->GetNACKCount ();
for (auto it = m_SentPackets.begin (); it != m_SentPackets.end ();)
{
@ -422,6 +432,7 @@ namespace stream @@ -422,6 +432,7 @@ namespace stream
for (int i = 0; i < nackCount; i++)
if (seqn == packet->GetNACK (i))
{
m_IsNAcked = true;
nacked = true;
break;
}
@ -447,8 +458,8 @@ namespace stream @@ -447,8 +458,8 @@ namespace stream
m_SentPackets.erase (it++);
m_LocalDestination.DeletePacket (sentPacket);
acknowledged = true;
if (m_WindowSize < WINDOW_SIZE)
m_WindowSize++; // slow start
if (m_WindowSize < MAX_WINDOW_SIZE)
m_WindowSize++;
}
else
break;
@ -456,30 +467,58 @@ namespace stream @@ -456,30 +467,58 @@ namespace stream
if (rttSample != INT_MAX)
{
if (firstRttSample)
{
m_RTT = rttSample;
m_PrewRTTSample = rttSample;
}
else
m_RTT = RTT_EWMA_ALPHA * rttSample + (1.0 - RTT_EWMA_ALPHA) * m_RTT;
// calculate jitter
int jitter = 0;
if (rttSample > m_PrewRTTSample)
jitter = rttSample - m_PrewRTTSample;
else if (rttSample < m_PrewRTTSample)
jitter = m_PrewRTTSample - rttSample;
else
jitter = std::round (rttSample / 10); // 10%
m_Jitter = std::round (RTT_EWMA_ALPHA * m_Jitter + (1.0 - RTT_EWMA_ALPHA) * jitter);
m_PrewRTTSample = rttSample;
//
// delay-based CC
if ((m_RTT > m_PrewRTT) && !m_IsWinDropped) // Drop window if RTT grows too fast, late detection
{
m_WindowSize >>= 1; // /2
m_IsWinDropped = true; // don't drop window twice
}
if (m_WindowSize < MIN_WINDOW_SIZE) m_WindowSize = MIN_WINDOW_SIZE;
int pacTime = std::round (m_RTT*1000/m_WindowSize);
m_PacingTime = std::max (MIN_PACING_TIME, pacTime);
m_PrewRTT = m_RTT * 1.1 + m_Jitter;
//
bool wasInitial = m_RTO == INITIAL_RTO;
m_RTO = std::max (MIN_RTO, (int)(m_RTT * 1.5)); // TODO: implement it better
m_RTO = std::max (MIN_RTO, (int)(m_RTT * 1.3 + m_Jitter)); // TODO: implement it better
if (wasInitial)
ScheduleResend ();
}
if (acknowledged && m_WindowSize >= WINDOW_SIZE)
if (m_WindowSize > int(m_SentPackets.size ()))
m_IsWinDropped = false;
if (acknowledged || m_IsNAcked)
{
// linear growth
if (ts > m_LastWindowSizeIncreaseTime + m_RTT)
{
m_WindowSize++;
if (m_WindowSize > MAX_WINDOW_SIZE) m_WindowSize = MAX_WINDOW_SIZE;
m_LastWindowSizeIncreaseTime = ts;
}
ScheduleResend ();
}
if ((m_SendBuffer.IsEmpty () && m_SentPackets.size () > 0) // tail loss
|| int(m_SentPackets.size ()) > m_WindowSize) // or we drop window
m_IsNAcked = true;
if (firstRttSample && m_RoutingSession)
m_RoutingSession->SetSharedRoutingPath (
std::make_shared<i2p::garlic::GarlicRoutingPath> (
i2p::garlic::GarlicRoutingPath{m_CurrentOutboundTunnel, m_CurrentRemoteLease, (int)m_RTT, 0, 0}));
if (m_SentPackets.empty ())
{
m_ResendTimer.cancel ();
m_SendTimer.cancel ();
}
if (acknowledged)
{
m_NumResendAttempts = 0;
@ -557,9 +596,10 @@ namespace stream @@ -557,9 +596,10 @@ namespace stream
void Stream::SendBuffer ()
{
ScheduleSend ();
int numMsgs = m_WindowSize - m_SentPackets.size ();
if (numMsgs <= 0) return; // window is full
else numMsgs = 1;
bool isNoAck = m_LastReceivedSequenceNumber < 0; // first packet
std::vector<Packet *> packets;
while ((m_Status == eStreamStatusNew) || (IsEstablished () && !m_SendBuffer.IsEmpty () && numMsgs > 0))
@ -873,6 +913,7 @@ namespace stream @@ -873,6 +913,7 @@ namespace stream
m_IsAckSendScheduled = false;
m_AckSendTimer.cancel ();
}
if (!packet->sendTime) packet->sendTime = i2p::util::GetMillisecondsSinceEpoch ();
SendPackets (std::vector<Packet *> { packet });
bool isEmpty = m_SentPackets.empty ();
m_SentPackets.insert (packet);
@ -906,7 +947,7 @@ namespace stream @@ -906,7 +947,7 @@ namespace stream
m_CurrentOutboundTunnel = routingPath->outboundTunnel;
m_CurrentRemoteLease = routingPath->remoteLease;
m_RTT = routingPath->rtt;
m_RTO = std::max (MIN_RTO, (int)(m_RTT * 1.5)); // TODO: implement it better
m_RTO = std::max (MIN_RTO, (int)(m_RTT * 1.3 + m_Jitter)); // TODO: implement it better
}
}
@ -935,7 +976,7 @@ namespace stream @@ -935,7 +976,7 @@ namespace stream
if (freshTunnel)
{
m_RTO = INITIAL_RTO;
m_TunnelsChangeSequenceNumber = m_SequenceNumber; // should be determined more precisely
// m_TunnelsChangeSequenceNumber = m_SequenceNumber; // should be determined more precisely
}
std::vector<i2p::tunnel::TunnelMessageBlock> msgs;
@ -988,6 +1029,40 @@ namespace stream @@ -988,6 +1029,40 @@ namespace stream
SendQuickAck ();
}
void Stream::ScheduleSend ()
{
if (m_Status != eStreamStatusTerminated)
{
m_SendTimer.cancel ();
m_SendTimer.expires_from_now (boost::posix_time::microseconds(m_PacingTime));
m_SendTimer.async_wait (std::bind (&Stream::HandleSendTimer,
shared_from_this (), std::placeholders::_1));
}
}
void Stream::HandleSendTimer (const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
if (m_IsNAcked) // || m_WindowSize < int(m_SentPackets.size ())) // resend one packet
ResendPacket ();
// delay-based CC
else if (!m_IsWinDropped && int(m_SentPackets.size ()) == m_WindowSize) // we sending packets too fast, early detection
{
m_WindowSize >>= 1; // /2
m_IsWinDropped = true; // don't drop window twice
if (m_WindowSize < MIN_WINDOW_SIZE) m_WindowSize = MIN_WINDOW_SIZE;
int pacTime = std::round (m_RTT*1000/m_WindowSize);
m_PacingTime = std::max (MIN_PACING_TIME, pacTime);
}
//
else if (m_WindowSize > int(m_SentPackets.size ())) // send one packet
SendBuffer ();
else // pass
ScheduleSend ();
}
}
void Stream::ScheduleResend ()
{
if (m_Status != eStreamStatusTerminated)
@ -1005,6 +1080,16 @@ namespace stream @@ -1005,6 +1080,16 @@ namespace stream
{
if (ecode != boost::asio::error::operation_aborted)
{
if (m_RTO > INITIAL_RTO) m_RTO = INITIAL_RTO;
m_SendTimer.cancel (); // if no ack's in RTO, disable fast retransmit
m_IsTimeOutResend = true;
m_IsNAcked = false;
ResendPacket (); // send one packet per RTO, waiting for ack
}
}
void Stream::ResendPacket ()
{
// check for resend attempts
if (m_NumResendAttempts >= MAX_NUM_RESEND_ATTEMPTS)
{
@ -1021,27 +1106,42 @@ namespace stream @@ -1021,27 +1106,42 @@ namespace stream
{
if (ts >= it->sendTime + m_RTO)
{
it->resent = true;
if (ts < it->sendTime + m_RTO*2)
it->resent = true;
else
it->resent = false;
it->sendTime = ts;
packets.push_back (it);
if (packets.size () >= 1) break;
}
}
// select tunnels if necessary and send
if (packets.size () > 0)
{
m_NumResendAttempts++;
if (m_IsNAcked) m_NumResendAttempts = 1;
else if (m_IsTimeOutResend) m_NumResendAttempts++;
if (m_NumResendAttempts == 1 && m_RTO != INITIAL_RTO)
{
// congestion avoidance
m_RTO *= 2;
m_WindowSize -= (m_WindowSize + WINDOW_SIZE_DROP_FRACTION) / WINDOW_SIZE_DROP_FRACTION; // adjustment >= 1
if (m_WindowSize < MIN_WINDOW_SIZE) m_WindowSize = MIN_WINDOW_SIZE;
// loss-based CC
if (!m_IsWinDropped)
{
m_WindowSize >>= 1; // /2
m_IsWinDropped = true; // don't drop window twice
if (m_WindowSize < MIN_WINDOW_SIZE) m_WindowSize = MIN_WINDOW_SIZE;
int pacTime = std::round (m_RTT*1000/m_WindowSize);
m_PacingTime = std::max (MIN_PACING_TIME, pacTime);
}
//
}
else
else if (m_IsTimeOutResend)
{
m_TunnelsChangeSequenceNumber = m_SequenceNumber;
m_IsTimeOutResend = false;
m_RTO = INITIAL_RTO; // drop RTO to initial upon tunnels pair change
m_WindowSize = INITIAL_WINDOW_SIZE;
m_IsWinDropped = true;
int pacTime = std::round (m_RTT*1000/m_WindowSize);
m_PacingTime = std::max (MIN_PACING_TIME, pacTime);
if (m_RoutingSession) m_RoutingSession->SetSharedRoutingPath (nullptr);
if (m_NumResendAttempts & 1)
{
@ -1058,9 +1158,11 @@ namespace stream @@ -1058,9 +1158,11 @@ namespace stream
}
}
SendPackets (packets);
if (m_IsNAcked) ScheduleSend ();
}
ScheduleResend ();
}
else
ScheduleSend ();
if (!m_IsNAcked) ScheduleResend ();
}
void Stream::ScheduleAck (int timeout)

23
libi2pd/Streaming.h
Unescape View File

@ -52,15 +52,17 @@ namespace stream @@ -52,15 +52,17 @@ namespace stream
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 = 9;
const int WINDOW_SIZE = 6; // in messages
const int MAX_NUM_RESEND_ATTEMPTS = 10;
const int MAX_STREAM_SPEED = 1730000000; // 1 - 1730000000 // in bytes/sec // no more than 1.73 Gbytes/s
const int MIN_PACING_TIME = 1000000 * STREAMING_MTU / MAX_STREAM_SPEED; // in microseconds
const int INITIAL_WINDOW_SIZE = 10;
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 = 0.125;
const double RTT_EWMA_ALPHA = 0.9;
const int MIN_RTO = 20; // in milliseconds
const int INITIAL_RTT = 8000; // in milliseconds
const int INITIAL_RTO = 9000; // in milliseconds
const int INITIAL_PACING_TIME = 1000 * INITIAL_RTT / INITIAL_WINDOW_SIZE; // in microseconds
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;
@ -231,8 +233,11 @@ namespace stream @@ -231,8 +233,11 @@ namespace stream
template<typename Buffer, typename ReceiveHandler>
void HandleReceiveTimer (const boost::system::error_code& ecode, const Buffer& buffer, ReceiveHandler handler, int remainingTimeout);
void ScheduleSend ();
void HandleSendTimer (const boost::system::error_code& ecode);
void ScheduleResend ();
void HandleResendTimer (const boost::system::error_code& ecode);
void ResendPacket ();
void ScheduleAck (int timeout);
void HandleAckSendTimer (const boost::system::error_code& ecode);
@ -242,8 +247,12 @@ namespace stream @@ -242,8 +247,12 @@ namespace stream
uint32_t m_SendStreamID, m_RecvStreamID, m_SequenceNumber;
uint32_t m_TunnelsChangeSequenceNumber;
int32_t m_LastReceivedSequenceNumber;
int32_t m_PreviousReceivedSequenceNumber;
StreamStatus m_Status;
bool m_IsAckSendScheduled;
bool m_IsNAcked;
bool m_IsWinDropped;
bool m_IsTimeOutResend;
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
@ -254,14 +263,14 @@ namespace stream @@ -254,14 +263,14 @@ namespace stream
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;
boost::asio::deadline_timer m_ReceiveTimer, m_SendTimer, m_ResendTimer, m_AckSendTimer;
size_t m_NumSentBytes, m_NumReceivedBytes;
uint16_t m_Port;
SendBufferQueue m_SendBuffer;
double m_RTT;
int m_WindowSize, m_RTO, m_AckDelay;
uint64_t m_LastWindowSizeIncreaseTime;
int m_WindowSize, m_RTO, m_AckDelay, m_PrewRTTSample, m_PrewRTT, m_Jitter;
uint64_t m_LastWindowSizeIncreaseTime, m_PacingTime;
int m_NumResendAttempts;
size_t m_MTU;
};

Write Preview
Loading…
Cancel
Save