59 lines
2.0 KiB
C++
59 lines
2.0 KiB
C++
/*
|
|
* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
#ifndef NET_DCSCTP_TX_RETRANSMISSION_TIMEOUT_H_
|
|
#define NET_DCSCTP_TX_RETRANSMISSION_TIMEOUT_H_
|
|
|
|
#include <cstdint>
|
|
#include <functional>
|
|
|
|
#include "net/dcsctp/public/dcsctp_options.h"
|
|
|
|
namespace dcsctp {
|
|
|
|
// Manages updating of the Retransmission Timeout (RTO) SCTP variable, which is
|
|
// used directly as the base timeout for T3-RTX and for other timers, such as
|
|
// delayed ack.
|
|
//
|
|
// When a round-trip-time (RTT) is calculated (outside this class), `Observe`
|
|
// is called, which calculates the retransmission timeout (RTO) value. The RTO
|
|
// value will become larger if the RTT is high and/or the RTT values are varying
|
|
// a lot, which is an indicator of a bad connection.
|
|
class RetransmissionTimeout {
|
|
public:
|
|
explicit RetransmissionTimeout(const DcSctpOptions& options);
|
|
|
|
// To be called when a RTT has been measured, to update the RTO value.
|
|
void ObserveRTT(DurationMs measured_rtt);
|
|
|
|
// Returns the Retransmission Timeout (RTO) value, in milliseconds.
|
|
DurationMs rto() const { return DurationMs(rto_); }
|
|
|
|
// Returns the smoothed RTT value, in milliseconds.
|
|
DurationMs srtt() const { return DurationMs(srtt_); }
|
|
|
|
private:
|
|
// Note that all intermediate state calculation is done in the floating point
|
|
// domain, to maintain precision.
|
|
const double min_rto_;
|
|
const double max_rto_;
|
|
const double max_rtt_;
|
|
// If this is the first measurement
|
|
bool first_measurement_ = true;
|
|
// Smoothed Round-Trip Time
|
|
double srtt_ = 0.0;
|
|
// Round-Trip Time Variation
|
|
double rttvar_ = 0.0;
|
|
// Retransmission Timeout
|
|
double rto_;
|
|
};
|
|
} // namespace dcsctp
|
|
|
|
#endif // NET_DCSCTP_TX_RETRANSMISSION_TIMEOUT_H_
|