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// Copyright (c) 2012 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/congestion_control/fix_rate_sender.h"
#include <math.h>
#include "base/logging.h"
#include "net/quic/quic_protocol.h"
namespace {
const int kInitialBitrate = 100000; // In bytes per second.
const uint64 kWindowSizeUs = 10000; // 10 ms.
}
namespace net {
FixRateSender::FixRateSender(const QuicClock* clock)
: bitrate_(QuicBandwidth::FromBytesPerSecond(kInitialBitrate)),
fix_rate_leaky_bucket_(bitrate_),
paced_sender_(bitrate_),
data_in_flight_(0),
latest_rtt_(QuicTime::Delta::Zero()) {
DLOG(INFO) << "FixRateSender";
}
FixRateSender::~FixRateSender() {
}
void FixRateSender::OnIncomingQuicCongestionFeedbackFrame(
const QuicCongestionFeedbackFrame& feedback,
QuicTime feedback_receive_time,
const SentPacketsMap& /*sent_packets*/) {
DCHECK(feedback.type == kFixRate) <<
"Invalid incoming CongestionFeedbackType:" << feedback.type;
if (feedback.type == kFixRate) {
bitrate_ = feedback.fix_rate.bitrate;
fix_rate_leaky_bucket_.SetDrainingRate(feedback_receive_time, bitrate_);
paced_sender_.UpdateBandwidthEstimate(feedback_receive_time, bitrate_);
}
// Silently ignore invalid messages in release mode.
}
void FixRateSender::OnIncomingAck(
QuicPacketSequenceNumber /*acked_sequence_number*/,
QuicByteCount bytes_acked,
QuicTime::Delta rtt) {
// RTT can't be negative.
DCHECK_LE(0, rtt.ToMicroseconds());
data_in_flight_ -= bytes_acked;
if (rtt.IsInfinite()) {
return;
}
latest_rtt_ = rtt;
}
void FixRateSender::OnIncomingLoss(QuicTime /*ack_receive_time*/) {
// Ignore losses for fix rate sender.
}
void FixRateSender::SentPacket(QuicTime sent_time,
QuicPacketSequenceNumber /*sequence_number*/,
QuicByteCount bytes,
Retransmission is_retransmission) {
fix_rate_leaky_bucket_.Add(sent_time, bytes);
paced_sender_.SentPacket(sent_time, bytes);
if (is_retransmission == NOT_RETRANSMISSION) {
data_in_flight_ += bytes;
}
}
void FixRateSender::AbandoningPacket(
QuicPacketSequenceNumber /*sequence_number*/,
QuicByteCount /*abandoned_bytes*/) {
}
QuicTime::Delta FixRateSender::TimeUntilSend(
QuicTime now,
Retransmission /*is_retransmission*/,
HasRetransmittableData /*has_retransmittable_data*/,
IsHandshake /* handshake */) {
if (CongestionWindow() > fix_rate_leaky_bucket_.BytesPending(now)) {
if (CongestionWindow() <= data_in_flight_) {
// We need an ack before we send more.
return QuicTime::Delta::Infinite();
}
return paced_sender_.TimeUntilSend(now, QuicTime::Delta::Zero());
}
QuicTime::Delta time_remaining = fix_rate_leaky_bucket_.TimeRemaining(now);
if (time_remaining.IsZero()) {
// We need an ack before we send more.
return QuicTime::Delta::Infinite();
}
return paced_sender_.TimeUntilSend(now, time_remaining);
}
QuicByteCount FixRateSender::CongestionWindow() {
QuicByteCount window_size_bytes = bitrate_.ToBytesPerPeriod(
QuicTime::Delta::FromMicroseconds(kWindowSizeUs));
// Make sure window size is not less than a packet.
return std::max(kMaxPacketSize, window_size_bytes);
}
QuicBandwidth FixRateSender::BandwidthEstimate() {
return bitrate_;
}
QuicTime::Delta FixRateSender::SmoothedRtt() {
// TODO(satyamshekhar): Calculate and return smoothed rtt.
return latest_rtt_;
}
QuicTime::Delta FixRateSender::RetransmissionDelay() {
// TODO(pwestin): Calculate and return retransmission delay.
// Use 2 * the latest RTT for now.
return latest_rtt_.Add(latest_rtt_);
}
} // namespace net
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