43 lines
1.5 KiB
C++
43 lines
1.5 KiB
C++
#include "congestion_control.hpp"
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#include "VpnPeer.hpp"
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CongestionController::CongestionController(const VpnPeer& peer):
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_peer(peer)
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{
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_last_seqno = _peer.get_loss_logger().get_cur_seqno();
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_loss_based.bandwidth = 3e5; // 300kBps seems a good value to start with
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_loss_based.prev_tot_sent = _peer.get_tot_bytes_sent();
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_loss_based.prev_time = std::chrono::steady_clock::now();
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}
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void CongestionController::update_lossbased() {
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const VpnPeer::LossReports& loss_rep = _peer.get_loss_reports();
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uint32_t delta_seqno = loss_rep.last_seqno - loss_rep.prev_seqno;
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unsigned int delta_losses = loss_rep.last_losses - loss_rep.prev_losses;
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double loss_rate = (double)delta_losses / (double)delta_seqno;
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auto cur_time = std::chrono::steady_clock::now();
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uint64_t cur_sent = _peer.get_tot_bytes_sent();
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double instant_bandwidth = /* byte per second */
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(double)(cur_sent - _loss_based.prev_tot_sent)
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/ (double)(std::chrono::duration_cast<std::chrono::microseconds>(
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cur_time - _loss_based.prev_time).count())
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* 1e6;
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_loss_based.prev_time = cur_time;
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_loss_based.prev_tot_sent = cur_sent;
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if(loss_rate < 0.02) {
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if(instant_bandwidth > 0.75 * _loss_based.bandwidth)
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_loss_based.bandwidth *= 1.05;
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}
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else if(loss_rate >= 0.1)
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_loss_based.bandwidth *= (1 - 0.5 * loss_rate);
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}
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uint64_t CongestionController::get_bandwidth() const {
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return _loss_based.bandwidth;
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}
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