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/*
* ngtcp2
*
* Copyright (c) 2021 ngtcp2 contributors
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef NGTCP2_BBR_H
#define NGTCP2_BBR_H
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <ngtcp2/ngtcp2.h>
#include "ngtcp2_cc.h"
#include "ngtcp2_window_filter.h"
typedef struct ngtcp2_rst ngtcp2_rst;
typedef enum ngtcp2_bbr_state {
NGTCP2_BBR_STATE_STARTUP,
NGTCP2_BBR_STATE_DRAIN,
NGTCP2_BBR_STATE_PROBE_BW_DOWN,
NGTCP2_BBR_STATE_PROBE_BW_CRUISE,
NGTCP2_BBR_STATE_PROBE_BW_REFILL,
NGTCP2_BBR_STATE_PROBE_BW_UP,
NGTCP2_BBR_STATE_PROBE_RTT,
} ngtcp2_bbr_state;
typedef enum ngtcp2_bbr_ack_phase {
NGTCP2_BBR_ACK_PHASE_ACKS_PROBE_STARTING,
NGTCP2_BBR_ACK_PHASE_ACKS_PROBE_STOPPING,
NGTCP2_BBR_ACK_PHASE_ACKS_PROBE_FEEDBACK,
NGTCP2_BBR_ACK_PHASE_ACKS_REFILLING,
} ngtcp2_bbr_ack_phase;
/*
* ngtcp2_cc_bbr is BBR v2 congestion controller, described in
* https://datatracker.ietf.org/doc/html/draft-cardwell-iccrg-bbr-congestion-control-01
*/
typedef struct ngtcp2_cc_bbr {
ngtcp2_cc cc;
uint64_t initial_cwnd;
ngtcp2_rst *rst;
ngtcp2_rand rand;
ngtcp2_rand_ctx rand_ctx;
/* max_bw_filter for tracking the maximum recent delivery rate
samples for estimating max_bw. */
ngtcp2_window_filter max_bw_filter;
ngtcp2_window_filter extra_acked_filter;
ngtcp2_duration min_rtt;
ngtcp2_tstamp min_rtt_stamp;
ngtcp2_tstamp probe_rtt_done_stamp;
int probe_rtt_round_done;
uint64_t prior_cwnd;
int idle_restart;
ngtcp2_tstamp extra_acked_interval_start;
uint64_t extra_acked_delivered;
/* Congestion signals */
int loss_in_round;
uint64_t bw_latest;
uint64_t inflight_latest;
/* Lower bounds */
uint64_t bw_lo;
uint64_t inflight_lo;
/* Round counting */
uint64_t next_round_delivered;
int round_start;
uint64_t round_count;
/* Full pipe */
uint64_t full_bw;
size_t full_bw_count;
int full_bw_reached;
int full_bw_now;
/* Pacing rate */
uint64_t pacing_gain_h;
ngtcp2_bbr_state state;
uint64_t cwnd_gain_h;
int loss_round_start;
uint64_t loss_round_delivered;
uint64_t rounds_since_bw_probe;
uint64_t max_bw;
uint64_t bw;
uint64_t cycle_count;
uint64_t extra_acked;
uint64_t bytes_lost_in_round;
size_t loss_events_in_round;
uint64_t offload_budget;
uint64_t probe_up_cnt;
ngtcp2_tstamp cycle_stamp;
ngtcp2_bbr_ack_phase ack_phase;
ngtcp2_duration bw_probe_wait;
int bw_probe_samples;
size_t bw_probe_up_rounds;
uint64_t bw_probe_up_acks;
uint64_t inflight_hi;
int probe_rtt_expired;
ngtcp2_duration probe_rtt_min_delay;
ngtcp2_tstamp probe_rtt_min_stamp;
int in_loss_recovery;
uint64_t round_count_at_recovery;
uint64_t max_inflight;
ngtcp2_tstamp congestion_recovery_start_ts;
} ngtcp2_cc_bbr;
void ngtcp2_cc_bbr_init(ngtcp2_cc_bbr *bbr, ngtcp2_log *log,
ngtcp2_conn_stat *cstat, ngtcp2_rst *rst,
ngtcp2_tstamp initial_ts, ngtcp2_rand rand,
const ngtcp2_rand_ctx *rand_ctx);
#endif /* NGTCP2_BBR_H */
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