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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/quic_connection_helper.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/task_runner.h"
#include "base/time.h"
#include "net/base/io_buffer.h"
#include "net/quic/congestion_control/quic_receipt_metrics_collector.h"
#include "net/quic/congestion_control/quic_send_scheduler.h"
#include "net/quic/quic_utils.h"
namespace net {
// Limit the number of packets we send per resend-alarm so we eventually cede.
// 10 is arbitrary.
const size_t kMaxPacketsPerResendAlarm = 10;
// The time to wait if an RTO alarm fires but is ignored due to truncated acks.
const int kExtraRTODelayUs = 500 * 1000;
QuicConnectionHelper::QuicConnectionHelper(base::TaskRunner* task_runner,
const QuicClock* clock,
QuicRandom* random_generator,
DatagramClientSocket* socket)
: ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)),
task_runner_(task_runner),
socket_(socket),
clock_(clock),
random_generator_(random_generator),
send_alarm_registered_(false),
timeout_alarm_registered_(false),
resend_alarm_registered_(false),
resend_alarm_running_(false) {
}
QuicConnectionHelper::~QuicConnectionHelper() {
}
void QuicConnectionHelper::SetConnection(QuicConnection* connection) {
connection_ = connection;
}
const QuicClock* QuicConnectionHelper::GetClock() const {
return clock_;
}
QuicRandom* QuicConnectionHelper::GetRandomGenerator() {
return random_generator_;
}
int QuicConnectionHelper::WritePacketToWire(
const QuicEncryptedPacket& packet,
int* error) {
if (connection_->ShouldSimulateLostPacket()) {
DLOG(INFO) << "Dropping packet due to fake packet loss.";
*error = 0;
return packet.length();
}
scoped_refptr<StringIOBuffer> buf(
new StringIOBuffer(std::string(packet.data(),
packet.length())));
int rv = socket_->Write(buf, packet.length(),
base::Bind(&QuicConnectionHelper::OnWriteComplete,
weak_factory_.GetWeakPtr()));
if (rv >= 0) {
*error = 0;
} else {
*error = rv;
rv = -1;
}
return rv;
}
void QuicConnectionHelper::SetResendAlarm(
QuicPacketSequenceNumber sequence_number,
QuicTime::Delta delay) {
if (!resend_alarm_registered_ &&
!resend_alarm_running_) {
resend_alarm_registered_ = true;
task_runner_->PostDelayedTask(
FROM_HERE,
base::Bind(&QuicConnectionHelper::OnResendAlarm,
weak_factory_.GetWeakPtr()),
base::TimeDelta::FromMicroseconds(delay.ToMicroseconds()));
}
resend_times_[sequence_number] = clock_->Now().Add(delay);
}
void QuicConnectionHelper::SetSendAlarm(QuicTime::Delta delay) {
send_alarm_registered_ = true;
task_runner_->PostDelayedTask(
FROM_HERE,
base::Bind(&QuicConnectionHelper::OnSendAlarm,
weak_factory_.GetWeakPtr()),
base::TimeDelta::FromMicroseconds(delay.ToMicroseconds()));
}
void QuicConnectionHelper::SetTimeoutAlarm(QuicTime::Delta delay) {
DCHECK(!timeout_alarm_registered_);
timeout_alarm_registered_ = true;
task_runner_->PostDelayedTask(
FROM_HERE,
base::Bind(&QuicConnectionHelper::OnTimeoutAlarm,
weak_factory_.GetWeakPtr()),
base::TimeDelta::FromMicroseconds(delay.ToMicroseconds()));
}
bool QuicConnectionHelper::IsSendAlarmSet() {
return send_alarm_registered_;
}
void QuicConnectionHelper::UnregisterSendAlarmIfRegistered() {
send_alarm_registered_ = false;
}
int QuicConnectionHelper::Read(IOBuffer* buf, int buf_len,
const CompletionCallback& callback) {
return socket_->Read(buf, buf_len, callback);
}
void QuicConnectionHelper::GetLocalAddress(IPEndPoint* local_address) {
socket_->GetLocalAddress(local_address);
}
void QuicConnectionHelper::GetPeerAddress(IPEndPoint* peer_address) {
socket_->GetPeerAddress(peer_address);
}
void QuicConnectionHelper::OnResendAlarm() {
// This guards against registering the alarm later than we should.
//
// If we have packet A and B in the list and we call MaybeResendPacketForRTO
// on A, that may trigger a call to SetResendAlarm if A is resent as C. In
// that case we don't want to register the alarm under SetResendAlarm; we
// want to set it to the RTO of B at the end of this method.
resend_alarm_registered_ = false;
resend_alarm_running_ = true;
for (size_t i = 0; i < kMaxPacketsPerResendAlarm; ++i) {
if (resend_times_.empty() ||
resend_times_.begin()->second > clock_->Now()) {
break;
}
QuicPacketSequenceNumber sequence_number = resend_times_.begin()->first;
if (!connection_->MaybeResendPacketForRTO(sequence_number)) {
DLOG(INFO) << "MaybeResendPacketForRTO failed: adding an extra delay.";
SetResendAlarm(sequence_number,
QuicTime::Delta::FromMicroseconds(kExtraRTODelayUs));
break;
}
resend_times_.erase(sequence_number);
}
// Nothing from here on does external calls.
resend_alarm_running_ = false;
if (resend_times_.empty()) {
return;
}
// We have packet remaining. Reschedule for the RTO of the oldest packet
// on the list.
SetResendAlarm(resend_times_.begin()->first,
resend_times_.begin()->second.Subtract(clock_->Now()));
}
void QuicConnectionHelper::OnSendAlarm() {
if (send_alarm_registered_) {
send_alarm_registered_ = false;
connection_->OnCanWrite();
}
}
void QuicConnectionHelper::OnTimeoutAlarm() {
timeout_alarm_registered_ = false;
connection_->CheckForTimeout();
}
void QuicConnectionHelper::OnWriteComplete(int result) {
// TODO(rch): Inform the connection about the result.
connection_->OnCanWrite();
}
} // namespace net
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