implemented TCP's slow start and congestion avoidance.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20734 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Hugo Santos
parent
d619e89985
commit
7d524fb79b
@ -116,6 +116,14 @@ segment_in_sequence(const tcp_segment_header &segment, int size,
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}
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static inline bool
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is_writable(tcp_state state)
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{
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return state == SYNCHRONIZE_SENT || state == SYNCHRONIZE_RECEIVED
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|| state == ESTABLISHED || state == FINISH_RECEIVED;
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}
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WaitList::WaitList(const char *name)
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{
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fSem = create_sem(0, name);
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@ -180,6 +188,8 @@ TCPEndpoint::TCPEndpoint(net_socket *socket)
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fReceiveQueue(socket->receive.buffer_size),
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fRoundTripTime(TCP_INITIAL_RTT),
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fReceivedTSval(0),
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fCongestionWindow(0),
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fSlowStartThreshold(0),
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fState(CLOSED),
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fFlags(FLAG_OPTION_WINDOW_SCALE | FLAG_OPTION_TIMESTAMP),
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fError(B_OK),
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@ -479,11 +489,11 @@ TCPEndpoint::Shutdown(int direction)
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status_t
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TCPEndpoint::SendData(net_buffer *buffer)
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{
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TRACE("SendData(buffer %p, size %lu, flags %lx)",
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buffer, buffer->size, buffer->flags);
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RecursiveLocker lock(fLock);
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TRACE("SendData(buffer %p, size %lu, flags %lx) [total %lu bytes]",
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buffer, buffer->size, buffer->flags, fSendQueue.Size());
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if (fState == CLOSED)
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return ENOTCONN;
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else if (fState == LISTEN) {
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@ -510,6 +520,8 @@ TCPEndpoint::SendData(net_buffer *buffer)
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fSendQueue.Add(buffer);
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}
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TRACE(" SendData(): %lu bytes used.", fSendQueue.Used());
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if (fState == ESTABLISHED || fState == FINISH_RECEIVED)
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_SendQueued();
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@ -524,12 +536,10 @@ TCPEndpoint::SendAvailable()
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ssize_t available;
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if (fState == FINISH_SENT || fState == FINISH_ACKNOWLEDGED
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|| fState == CLOSING || fState == WAIT_FOR_FINISH_ACKNOWLEDGE
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|| fState == TIME_WAIT || fState == LISTEN || fState == CLOSED)
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available = EPIPE;
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else
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if (is_writable(fState))
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available = fSendQueue.Free();
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else
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available = EPIPE;
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TRACE("SendAvailable(): %li", available);
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return available;
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@ -603,8 +613,7 @@ TCPEndpoint::ReadData(size_t numBytes, uint32 flags, net_buffer** _buffer)
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}
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}
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TRACE(" ReadData(): read %lu bytes, %lu are available.",
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numBytes, fReceiveQueue.Available());
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TRACE(" ReadData(): %lu are available.", fReceiveQueue.Available());
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if (numBytes < fReceiveQueue.Available())
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fReceiveList.Signal();
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@ -745,7 +754,10 @@ TCPEndpoint::Spawn(TCPEndpoint *parent, tcp_segment_header &segment,
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if (_PrepareSendPath((sockaddr *)&socket->peer) < B_OK)
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return DROP;
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_PrepareReceivePath(parent, segment);
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fOptions = parent->fOptions;
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fAcceptSemaphore = parent->fAcceptSemaphore;
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_PrepareReceivePath(segment);
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// send SYN+ACK
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if (_SendQueued() < B_OK)
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@ -777,7 +789,8 @@ TCPEndpoint::_SynchronizeSentReceive(tcp_segment_header &segment, net_buffer *bu
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if ((segment.flags & TCP_FLAG_SYNCHRONIZE) == 0)
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return DROP;
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_PrepareReceivePath(NULL, segment);
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fSendUnacknowledged = segment.acknowledge;
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_PrepareReceivePath(segment);
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if (segment.flags & TCP_FLAG_ACKNOWLEDGE) {
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_MarkEstablished();
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@ -859,21 +872,11 @@ TCPEndpoint::_SegmentReceived(tcp_segment_header &segment, net_buffer *buffer)
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TRACE("Receive(): header prediction send!");
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// and it only acknowledges outstanding data
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// TODO: update RTT estimators
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fSendQueue.RemoveUntil(segment.acknowledge);
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fSendUnacknowledged = segment.acknowledge;
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_Acknowledged(segment.acknowledge);
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// stop retransmit timer
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gStackModule->cancel_timer(&fRetransmitTimer);
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// notify threads waiting on the socket to become writable again
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fSendList.Signal();
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// TODO: real conditional locking needed!
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gSocketModule->notify(socket, B_SELECT_WRITE, fSendWindow);
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// if there is data left to be send, send it now
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_SendQueued();
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return DROP;
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}
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} else if (segment.acknowledge == fSendUnacknowledged
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@ -1017,7 +1020,12 @@ TCPEndpoint::_SendQueued(bool force)
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sendWindow = 1;
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}
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int32 length = min_c(available, sendWindow) - (fSendNext - fSendUnacknowledged);
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if (fCongestionWindow > 0)
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sendWindow = min_c(sendWindow, fCongestionWindow);
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int32 length = min_c(available, sendWindow)
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- (fSendNext - fSendUnacknowledged);
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if (length < 0) {
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// either the window shrank, or we sent a still unacknowledged FIN
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length = 0;
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@ -1091,9 +1099,10 @@ TCPEndpoint::_SendQueued(bool force)
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buffer, buffer->size, AddressString(Domain(),
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(sockaddr *)&buffer->source, true).Data(), AddressString(Domain(),
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(sockaddr *)&buffer->destination, true).Data());
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TRACE(" flags 0x%x, seq %lu, ack %lu, rwnd %hu",
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segment.flags, segment.sequence, segment.acknowledge,
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segment.advertised_window);
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TRACE(" flags 0x%x, seq %lu, ack %lu, rwnd %hu, cwnd %lu"
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", ssthresh %lu", segment.flags, segment.sequence,
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segment.acknowledge, segment.advertised_window,
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fCongestionWindow, fSlowStartThreshold);
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status = add_tcp_header(AddressModule(), segment, buffer);
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if (status != B_OK) {
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@ -1342,11 +1351,7 @@ TCPEndpoint::_Receive(tcp_segment_header &segment, net_buffer *buffer)
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gStackModule->set_timer(&fRetransmitTimer, 1000000LL);
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}
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fSendUnacknowledged = segment.acknowledge;
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fSendQueue.RemoveUntil(segment.acknowledge);
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if (fSendNext < fSendUnacknowledged)
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fSendNext = fSendUnacknowledged;
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_Acknowledged(segment.acknowledge);
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if (segment.acknowledge > fSendQueue.LastSequence()
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&& fState > ESTABLISHED) {
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@ -1496,24 +1501,16 @@ TCPEndpoint::_AddData(tcp_segment_header &segment, net_buffer *buffer)
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void
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TCPEndpoint::_PrepareReceivePath(TCPEndpoint *parent,
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tcp_segment_header &segment)
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TCPEndpoint::_PrepareReceivePath(tcp_segment_header &segment)
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{
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fInitialReceiveSequence = segment.sequence;
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// count the received SYN
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segment.sequence++;
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if (parent == NULL)
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fSendUnacknowledged = segment.acknowledge;
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fReceiveNext = segment.sequence;
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fReceiveQueue.SetInitialSequence(segment.sequence);
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if (parent) {
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fOptions = parent->fOptions;
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fAcceptSemaphore = parent->fAcceptSemaphore;
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}
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if ((fOptions & TCP_NOOPT) == 0) {
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if (segment.max_segment_size > 0)
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fSendMaxSegmentSize = segment.max_segment_size;
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@ -1531,6 +1528,9 @@ TCPEndpoint::_PrepareReceivePath(TCPEndpoint *parent,
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else
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fFlags &= ~FLAG_OPTION_TIMESTAMP;
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}
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fCongestionWindow = 2 * fSendMaxSegmentSize;
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fSlowStartThreshold = (uint32)segment.advertised_window << fSendWindowShift;
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}
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@ -1571,6 +1571,61 @@ TCPEndpoint::_PrepareSendPath(const sockaddr *peer)
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}
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void
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TCPEndpoint::_Acknowledged(tcp_sequence acknowledge)
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{
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size_t previouslyUsed = fSendQueue.Used();
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fSendQueue.RemoveUntil(acknowledge);
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fSendUnacknowledged = acknowledge;
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if (fSendNext < fSendUnacknowledged)
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fSendNext = fSendUnacknowledged;
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// TODO: update RTT estimators
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if (fSendQueue.Used() < previouslyUsed) {
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// this ACK acknowledged data
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if (is_writable(fState)) {
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// notify threads waiting on the socket to become writable again
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fSendList.Signal();
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gSocketModule->notify(socket, B_SELECT_WRITE, fSendQueue.Used());
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}
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if (fCongestionWindow < fSlowStartThreshold)
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fCongestionWindow += fSendMaxSegmentSize;
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}
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if (fCongestionWindow >= fSlowStartThreshold) {
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uint32 increment = fSendMaxSegmentSize * fSendMaxSegmentSize;
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if (increment < fCongestionWindow)
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increment = 1;
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else
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increment /= fCongestionWindow;
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fCongestionWindow += increment;
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}
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// if there is data left to be send, send it now
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_SendQueued();
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}
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void
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TCPEndpoint::_Retransmit()
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{
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fSendNext = fSendUnacknowledged;
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_SendQueued();
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fSendNext = fSendMax;
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fSlowStartThreshold = max_c((fSendMax - fSendUnacknowledged) / 2,
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2 * fSendMaxSegmentSize);
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fCongestionWindow = fSendMaxSegmentSize;
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}
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// #pragma mark - timer
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@ -1583,9 +1638,7 @@ TCPEndpoint::_RetransmitTimer(net_timer *timer, void *data)
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if (!locker.IsLocked())
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return;
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endpoint->fSendNext = endpoint->fSendUnacknowledged;
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endpoint->_SendQueued();
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endpoint->fSendNext = endpoint->fSendMax;
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endpoint->_Retransmit();
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}
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@ -102,9 +102,10 @@ class TCPEndpoint : public net_protocol {
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void _MarkEstablished();
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status_t _WaitForEstablished(RecursiveLocker &lock, bigtime_t timeout);
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void _AddData(tcp_segment_header &segment, net_buffer *buffer);
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void _PrepareReceivePath(TCPEndpoint *parent,
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tcp_segment_header &segment);
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void _PrepareReceivePath(tcp_segment_header &segment);
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status_t _PrepareSendPath(const sockaddr *peer);
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void _Acknowledged(tcp_sequence acknowledge);
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void _Retransmit();
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static void _TimeWaitTimer(net_timer *timer, void *data);
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static void _RetransmitTimer(net_timer *timer, void *data);
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