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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,
NGTCP2_BBR_STATE_PROBE_RTT,
} ngtcp2_bbr_state;
/*
* ngtcp2_bbr_cc is BBR congestion controller, described in
* https://tools.ietf.org/html/draft-cardwell-iccrg-bbr-congestion-control-00
*/
typedef struct ngtcp2_bbr_cc {
ngtcp2_cc_base ccb;
/* The max filter used to estimate BBR.BtlBw. */
ngtcp2_window_filter btl_bw_filter;
uint64_t initial_cwnd;
ngtcp2_rst *rst;
ngtcp2_rand rand;
ngtcp2_rand_ctx rand_ctx;
/* BBR variables */
/* The dynamic gain factor used to scale BBR.BtlBw to
produce BBR.pacing_rate. */
double pacing_gain;
/* The dynamic gain factor used to scale the estimated BDP to produce a
congestion window (cwnd). */
double cwnd_gain;
uint64_t full_bw;
/* packet.delivered value denoting the end of a packet-timed round trip. */
uint64_t next_round_delivered;
/* Count of packet-timed round trips. */
uint64_t round_count;
uint64_t prior_cwnd;
/* target_cwnd is the upper bound on the volume of data BBR
allows in flight. */
uint64_t target_cwnd;
/* BBR's estimated bottleneck bandwidth available to the
transport flow, estimated from the maximum delivery rate sample in a
sliding window. */
uint64_t btl_bw;
/* BBR's estimated two-way round-trip propagation delay of
the path, estimated from the windowed minimum recent round-trip delay
sample. */
ngtcp2_duration rt_prop;
/* The wall clock time at which the current BBR.RTProp
sample was obtained. */
ngtcp2_tstamp rtprop_stamp;
ngtcp2_tstamp cycle_stamp;
ngtcp2_tstamp probe_rtt_done_stamp;
/* congestion_recovery_start_ts is the time when congestion recovery
period started.*/
ngtcp2_tstamp congestion_recovery_start_ts;
uint64_t congestion_recovery_next_round_delivered;
size_t full_bw_count;
size_t cycle_index;
ngtcp2_bbr_state state;
/* A boolean that records whether BBR estimates that it has ever fully
utilized its available bandwidth ("filled the pipe"). */
int filled_pipe;
/* A boolean that BBR sets to true once per packet-timed round trip,
on ACKs that advance BBR.round_count. */
int round_start;
int rtprop_expired;
int idle_restart;
int packet_conservation;
int probe_rtt_round_done;
/* in_loss_recovery becomes nonzero when BBR enters loss recovery
period. */
int in_loss_recovery;
} ngtcp2_bbr_cc;
int ngtcp2_cc_bbr_cc_init(ngtcp2_cc *cc, ngtcp2_log *log,
ngtcp2_conn_stat *cstat, ngtcp2_rst *rst,
ngtcp2_tstamp initial_ts, ngtcp2_rand rand,
const ngtcp2_rand_ctx *rand_ctx,
const ngtcp2_mem *mem);
void ngtcp2_cc_bbr_cc_free(ngtcp2_cc *cc, const ngtcp2_mem *mem);
void ngtcp2_bbr_cc_init(ngtcp2_bbr_cc *bbr_cc, ngtcp2_conn_stat *cstat,
ngtcp2_rst *rst, ngtcp2_tstamp initial_ts,
ngtcp2_rand rand, const ngtcp2_rand_ctx *rand_ctx,
ngtcp2_log *log);
void ngtcp2_bbr_cc_free(ngtcp2_bbr_cc *cc);
void ngtcp2_cc_bbr_cc_on_pkt_acked(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
const ngtcp2_cc_pkt *pkt, ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_congestion_event(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
ngtcp2_tstamp sent_ts, ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_on_spurious_congestion(ngtcp2_cc *ccx,
ngtcp2_conn_stat *cstat,
ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_on_persistent_congestion(ngtcp2_cc *cc,
ngtcp2_conn_stat *cstat,
ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_on_ack_recv(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
const ngtcp2_cc_ack *ack, ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_on_pkt_sent(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
const ngtcp2_cc_pkt *pkt);
void ngtcp2_cc_bbr_cc_new_rtt_sample(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_reset(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
ngtcp2_tstamp ts);
void ngtcp2_cc_bbr_cc_event(ngtcp2_cc *cc, ngtcp2_conn_stat *cstat,
ngtcp2_cc_event_type event, ngtcp2_tstamp ts);
#endif /* NGTCP2_BBR_H */
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