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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/quic/quic_flow_controller.h"
#include "base/basictypes.h"
#include "net/quic/quic_connection.h"
#include "net/quic/quic_flags.h"
#include "net/quic/quic_protocol.h"
namespace net {
#define ENDPOINT (is_server_ ? "Server: " : " Client: ")
QuicFlowController::QuicFlowController(QuicStreamId id,
bool is_server,
uint64 send_window_offset,
uint64 receive_window_offset,
uint64 max_receive_window)
: id_(id),
is_enabled_(true),
is_server_(is_server),
bytes_consumed_(0),
bytes_buffered_(0),
bytes_sent_(0),
send_window_offset_(send_window_offset),
receive_window_offset_(receive_window_offset),
max_receive_window_(max_receive_window) {
DVLOG(1) << ENDPOINT << "Created flow controller for stream " << id_
<< ", setting initial receive window offset to: "
<< receive_window_offset_
<< ", max receive window to: "
<< max_receive_window_
<< ", setting send window offset to: " << send_window_offset_;
}
void QuicFlowController::AddBytesConsumed(uint64 bytes_consumed) {
if (!IsEnabled()) {
return;
}
bytes_consumed_ += bytes_consumed;
DVLOG(1) << ENDPOINT << "Stream " << id_ << " consumed: " << bytes_consumed_;
}
void QuicFlowController::AddBytesBuffered(uint64 bytes_buffered) {
if (!IsEnabled()) {
return;
}
bytes_buffered_ += bytes_buffered;
DVLOG(1) << ENDPOINT << "Stream " << id_ << " buffered: " << bytes_buffered_;
}
void QuicFlowController::RemoveBytesBuffered(uint64 bytes_buffered) {
if (!IsEnabled()) {
return;
}
if (bytes_buffered_ < bytes_buffered) {
LOG(DFATAL) << "Trying to remove " << bytes_buffered << " bytes, when only "
<< bytes_buffered_ << " bytes are buffered";
bytes_buffered_ = 0;
return;
}
bytes_buffered_ -= bytes_buffered;
DVLOG(1) << ENDPOINT << "Stream " << id_ << " buffered: " << bytes_buffered_;
}
void QuicFlowController::AddBytesSent(uint64 bytes_sent) {
if (!IsEnabled()) {
return;
}
if (bytes_sent_ + bytes_sent > send_window_offset_) {
LOG(DFATAL) << "Trying to send an extra " << bytes_sent
<< " bytes, when bytes_sent = " << bytes_sent_
<< ", and send_window = " << send_window_offset_;
bytes_sent_ = send_window_offset_;
return;
}
bytes_sent_ += bytes_sent;
DVLOG(1) << ENDPOINT << "Stream " << id_ << " sent: " << bytes_sent_;
}
bool QuicFlowController::FlowControlViolation() {
if (receive_window_offset_ < TotalReceivedBytes()) {
// TODO(rjshade): Lower severity from DFATAL once we have established that
// flow control is working correctly.
LOG(DFATAL)
<< ENDPOINT << "Flow control violation on stream " << id_
<< ", receive window: " << receive_window_offset_
<< ", bytes received: " << TotalReceivedBytes();
return true;
}
return false;
}
void QuicFlowController::MaybeSendWindowUpdate(QuicConnection* connection) {
if (!IsEnabled()) {
return;
}
// Send WindowUpdate to increase receive window if
// (receive window offset - consumed bytes) < (max window / 2).
// This is behaviour copied from SPDY.
size_t consumed_window = receive_window_offset_ - bytes_consumed_;
size_t threshold = (max_receive_window_ / 2);
if (consumed_window < threshold) {
// Update our receive window.
receive_window_offset_ += (max_receive_window_ - consumed_window);
DVLOG(1) << ENDPOINT << "Sending WindowUpdate frame for stream " << id_
<< ", consumed bytes: " << bytes_consumed_
<< ", consumed window: " << consumed_window
<< ", and threshold: " << threshold
<< ", and max recvw: " << max_receive_window_
<< ". New receive window offset is: " << receive_window_offset_;
// Inform the peer of our new receive window.
connection->SendWindowUpdate(id_, receive_window_offset_);
}
}
void QuicFlowController::MaybeSendBlocked(QuicConnection* connection) {
if (!IsEnabled()) {
return;
}
if (SendWindowSize() == 0) {
DVLOG(1) << ENDPOINT << "Stream " << id_ << " is flow control blocked. "
<< "Send window: " << SendWindowSize()
<< ", bytes sent: " << bytes_sent_
<< ", send limit: " << send_window_offset_;
// The entire send_window has been consumed, we are now flow control
// blocked.
connection->SendBlocked(id_);
}
}
bool QuicFlowController::UpdateSendWindowOffset(uint64 new_send_window_offset) {
// Only update if send window has increased.
if (new_send_window_offset <= send_window_offset_) {
return false;
}
DVLOG(1) << ENDPOINT << "UpdateSendWindowOffset for stream " << id_
<< " with new offset " << new_send_window_offset
<< " , current offset: " << send_window_offset_;
send_window_offset_ = new_send_window_offset;
return true;
}
void QuicFlowController::Disable() {
is_enabled_ = false;
}
bool QuicFlowController::IsEnabled() const {
return FLAGS_enable_quic_stream_flow_control && is_enabled_;
}
bool QuicFlowController::IsBlocked() const {
return IsEnabled() && SendWindowSize() == 0;
}
uint64 QuicFlowController::SendWindowSize() const {
if (bytes_sent_ > send_window_offset_) {
return 0;
}
return send_window_offset_ - bytes_sent_;
}
uint64 QuicFlowController::TotalReceivedBytes() const {
return bytes_consumed_ + bytes_buffered_;
}
} // namespace net
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