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// Copyright 2013 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/tools/quic/test_tools/packet_dropping_test_writer.h"
#include <limits>
#include "base/rand_util.h"
#include "net/tools/quic/quic_epoll_connection_helper.h"
#include "net/tools/quic/quic_socket_utils.h"
namespace net {
namespace test {
// An alarm that is scheduled if a blocked socket is simulated to indicate
// it's writable again.
class WriteUnblockedAlarm : public QuicAlarm::Delegate {
public:
explicit WriteUnblockedAlarm(PacketDroppingTestWriter* writer)
: writer_(writer) {}
QuicTime OnAlarm() override {
DVLOG(1) << "Unblocking socket.";
writer_->OnCanWrite();
return QuicTime::Zero();
}
private:
PacketDroppingTestWriter* writer_;
};
// An alarm that is scheduled every time a new packet is to be written at a
// later point.
class DelayAlarm : public QuicAlarm::Delegate {
public:
explicit DelayAlarm(PacketDroppingTestWriter* writer) : writer_(writer) {}
QuicTime OnAlarm() override { return writer_->ReleaseOldPackets(); }
private:
PacketDroppingTestWriter* writer_;
};
PacketDroppingTestWriter::PacketDroppingTestWriter()
: clock_(nullptr),
cur_buffer_size_(0),
num_calls_to_write_(0),
config_mutex_(),
fake_packet_loss_percentage_(0),
fake_drop_first_n_packets_(0),
fake_blocked_socket_percentage_(0),
fake_packet_reorder_percentage_(0),
fake_packet_delay_(QuicTime::Delta::Zero()),
fake_bandwidth_(QuicBandwidth::Zero()),
buffer_size_(0) {
uint32_t seed = base::RandInt(0, std::numeric_limits<int32_t>::max());
VLOG(1) << "Seeding packet loss with " << seed;
simple_random_.set_seed(seed);
}
PacketDroppingTestWriter::~PacketDroppingTestWriter() {}
void PacketDroppingTestWriter::Initialize(QuicConnectionHelperInterface* helper,
Delegate* on_can_write) {
clock_ = helper->GetClock();
write_unblocked_alarm_.reset(
helper->CreateAlarm(new WriteUnblockedAlarm(this)));
delay_alarm_.reset(helper->CreateAlarm(new DelayAlarm(this)));
on_can_write_.reset(on_can_write);
}
WriteResult PacketDroppingTestWriter::WritePacket(
const char* buffer,
size_t buf_len,
const IPAddress& self_address,
const IPEndPoint& peer_address,
PerPacketOptions* options) {
++num_calls_to_write_;
ReleaseOldPackets();
base::AutoLock locked(config_mutex_);
if (fake_drop_first_n_packets_ > 0 &&
num_calls_to_write_ <=
static_cast<uint64_t>(fake_drop_first_n_packets_)) {
DVLOG(1) << "Dropping first " << fake_drop_first_n_packets_
<< " packets (packet number " << num_calls_to_write_ << ")";
return WriteResult(WRITE_STATUS_OK, buf_len);
}
if (fake_packet_loss_percentage_ > 0 &&
simple_random_.RandUint64() % 100 <
static_cast<uint64_t>(fake_packet_loss_percentage_)) {
DVLOG(1) << "Dropping packet.";
return WriteResult(WRITE_STATUS_OK, buf_len);
}
if (fake_blocked_socket_percentage_ > 0 &&
simple_random_.RandUint64() % 100 <
static_cast<uint64_t>(fake_blocked_socket_percentage_)) {
CHECK(on_can_write_.get() != nullptr);
DVLOG(1) << "Blocking socket.";
if (!write_unblocked_alarm_->IsSet()) {
// Set the alarm to fire immediately.
write_unblocked_alarm_->Set(clock_->ApproximateNow());
}
return WriteResult(WRITE_STATUS_BLOCKED, EAGAIN);
}
if (!fake_packet_delay_.IsZero() || !fake_bandwidth_.IsZero()) {
if (buffer_size_ > 0 && buf_len + cur_buffer_size_ > buffer_size_) {
// Drop packets which do not fit into the buffer.
DVLOG(1) << "Dropping packet because the buffer is full.";
return WriteResult(WRITE_STATUS_OK, buf_len);
}
// Queue it to be sent.
QuicTime send_time = clock_->ApproximateNow().Add(fake_packet_delay_);
if (!fake_bandwidth_.IsZero()) {
// Calculate a time the bandwidth limit would impose.
QuicTime::Delta bandwidth_delay = QuicTime::Delta::FromMicroseconds(
(buf_len * kNumMicrosPerSecond) / fake_bandwidth_.ToBytesPerSecond());
send_time = delayed_packets_.empty()
? send_time.Add(bandwidth_delay)
: delayed_packets_.back().send_time.Add(bandwidth_delay);
}
std::unique_ptr<PerPacketOptions> delayed_options;
if (options != nullptr) {
delayed_options.reset(options->Clone());
}
delayed_packets_.push_back(
DelayedWrite(buffer, buf_len, self_address, peer_address,
std::move(delayed_options), send_time));
cur_buffer_size_ += buf_len;
// Set the alarm if it's not yet set.
if (!delay_alarm_->IsSet()) {
delay_alarm_->Set(send_time);
}
return WriteResult(WRITE_STATUS_OK, buf_len);
}
return QuicPacketWriterWrapper::WritePacket(buffer, buf_len, self_address,
peer_address, options);
}
bool PacketDroppingTestWriter::IsWriteBlocked() const {
if (write_unblocked_alarm_.get() != nullptr &&
write_unblocked_alarm_->IsSet()) {
return true;
}
return QuicPacketWriterWrapper::IsWriteBlocked();
}
void PacketDroppingTestWriter::SetWritable() {
if (write_unblocked_alarm_.get() != nullptr &&
write_unblocked_alarm_->IsSet()) {
write_unblocked_alarm_->Cancel();
}
QuicPacketWriterWrapper::SetWritable();
}
QuicTime PacketDroppingTestWriter::ReleaseNextPacket() {
if (delayed_packets_.empty()) {
return QuicTime::Zero();
}
base::AutoLock locked(config_mutex_);
DelayedPacketList::iterator iter = delayed_packets_.begin();
// Determine if we should re-order.
if (delayed_packets_.size() > 1 && fake_packet_reorder_percentage_ > 0 &&
simple_random_.RandUint64() % 100 <
static_cast<uint64_t>(fake_packet_reorder_percentage_)) {
DVLOG(1) << "Reordering packets.";
++iter;
// Swap the send times when re-ordering packets.
delayed_packets_.begin()->send_time = iter->send_time;
}
DVLOG(1) << "Releasing packet. " << (delayed_packets_.size() - 1)
<< " remaining.";
// Grab the next one off the queue and send it.
QuicPacketWriterWrapper::WritePacket(
iter->buffer.data(), iter->buffer.length(), iter->self_address,
iter->peer_address, iter->options.get());
DCHECK_GE(cur_buffer_size_, iter->buffer.length());
cur_buffer_size_ -= iter->buffer.length();
delayed_packets_.erase(iter);
// If there are others, find the time for the next to be sent.
if (delayed_packets_.empty()) {
return QuicTime::Zero();
}
return delayed_packets_.begin()->send_time;
}
QuicTime PacketDroppingTestWriter::ReleaseOldPackets() {
while (!delayed_packets_.empty()) {
QuicTime next_send_time = delayed_packets_.front().send_time;
if (next_send_time > clock_->Now()) {
return next_send_time;
}
ReleaseNextPacket();
}
return QuicTime::Zero();
}
void PacketDroppingTestWriter::OnCanWrite() {
on_can_write_->OnCanWrite();
}
PacketDroppingTestWriter::DelayedWrite::DelayedWrite(
const char* buffer,
size_t buf_len,
const IPAddress& self_address,
const IPEndPoint& peer_address,
std::unique_ptr<PerPacketOptions> options,
QuicTime send_time)
: buffer(buffer, buf_len),
self_address(self_address),
peer_address(peer_address),
options(std::move(options)),
send_time(send_time) {}
// TODO(rtenneti): on windows RValue reference gives errors.
PacketDroppingTestWriter::DelayedWrite::DelayedWrite(
PacketDroppingTestWriter::DelayedWrite&& other) = default;
// TODO(rtenneti): on windows RValue reference gives errors.
// IPAddress has no move assignment operator.
//
// PacketDroppingTestWriter::DelayedWrite&
// PacketDroppingTestWriter::DelayedWrite::operator=(
// PacketDroppingTestWriter::DelayedWrite&& other) = default;
PacketDroppingTestWriter::DelayedWrite::~DelayedWrite() {}
} // namespace test
} // namespace net
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