net/quic/quic_flags_list.h - chromium/src - Git at Google

 // Copyright 2014 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.

 // This file intentionally does not have header guards, it's included
 // inside a macro to generate values. The following line silences a
 // presubmit warning that would otherwise be triggered by this:
 // no-include-guard-because-multiply-included
 // NOLINT(build/header_guard)

 // This file contains the list of QUIC protocol flags.

 // Time period for which a given connection_id should live in the time-wait
 // state.
 QUIC_FLAG(int64_t, FLAGS_quic_time_wait_list_seconds, 200)

 // Currently, this number is quite conservative.  The max QPS limit for an
 // individual server silo is currently set to 1000 qps, though the actual max
 // that we see in the wild is closer to 450 qps.  Regardless, this means that
 // the longest time-wait list we should see is 200 seconds * 1000 qps, 200000.
 // Of course, there are usually many queries per QUIC connection, so we allow a
 // factor of 3 leeway.
 //
 // Maximum number of connections on the time-wait list. A negative value implies
 // no configured limit.
 QUIC_FLAG(int64_t, FLAGS_quic_time_wait_list_max_connections, 600000)

 // If true, require handshake confirmation for QUIC connections, functionally
 // disabling 0-rtt handshakes.
 // TODO(rtenneti): Enable this flag after CryptoServerTest's are fixed.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_require_handshake_confirmation,
           false)

 // If true, disable pacing in QUIC.
 QUIC_FLAG(bool, FLAGS_quic_disable_pacing_for_perf_tests, false)

 // If true, enforce that QUIC CHLOs fit in one packet.
 QUIC_FLAG(bool, FLAGS_quic_enforce_single_packet_chlo, true)

 // If true, allows packets to be buffered in anticipation of a future CHLO, and
 // allow CHLO packets to be buffered until next iteration of the event loop.
 QUIC_FLAG(bool, FLAGS_quic_allow_chlo_buffering, true)

 // If greater than zero, mean RTT variation is multiplied by the specified
 // factor and added to the congestion window limit.
 QUIC_FLAG(double, FLAGS_quic_bbr_rtt_variation_weight, 0.0f)

 // Congestion window gain for QUIC BBR during PROBE_BW phase.
 QUIC_FLAG(double, FLAGS_quic_bbr_cwnd_gain, 2.0f)

 // If true, adjust congestion window when doing bandwidth resumption in BBR.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_bbr_cwnd_in_bandwidth_resumption,
           true)

 // When true, defaults to BBR congestion control instead of Cubic.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_to_bbr, false)

 // If true, use BBRv2 as the default congestion controller.
 // Takes precedence over --quic_default_to_bbr.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_to_bbr_v2, false)

 // If buffered data in QUIC stream is less than this threshold, buffers all
 // provided data or asks upper layer for more data.
 QUIC_FLAG(uint32_t, FLAGS_quic_buffered_data_threshold, 8192u)

 // Max size of data slice in bytes for QUIC stream send buffer.
 QUIC_FLAG(uint32_t, FLAGS_quic_send_buffer_max_data_slice_size, 4096u)

 // Anti-amplification factor. Before address validation, server will
 // send no more than factor times bytes received.
 QUIC_FLAG(int32_t, FLAGS_quic_anti_amplification_factor, 3)

 // When true, set the initial congestion control window from connection options
 // in QuicSentPacketManager rather than TcpCubicSenderBytes.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_unified_iw_options, false)

 // Number of packets that the pacing sender allows in bursts during pacing.
 QUIC_FLAG(int32_t, FLAGS_quic_lumpy_pacing_size, 2)

 // Congestion window fraction that the pacing sender allows in bursts during
 // pacing.
 QUIC_FLAG(double, FLAGS_quic_lumpy_pacing_cwnd_fraction, 0.25f)

 // Default enables QUIC ack decimation and adds a connection option to disable
 // it.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_ack_decimation, true)

 // If true, QUIC offload pacing when using USPS as egress method.
 QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_offload_pacing_to_usps2, false)

 // Max time that QUIC can pace packets into the future in ms.
 QUIC_FLAG(int32_t, FLAGS_quic_max_pace_time_into_future_ms, 10)

 // Smoothed RTT fraction that a connection can pace packets into the future.
 QUIC_FLAG(double, FLAGS_quic_pace_time_into_future_srtt_fraction, 0.125f)

 // Mechanism to override version label and ALPN for IETF interop.
 QUIC_FLAG(int32_t, FLAGS_quic_ietf_draft_version, 0)

 // If true, stop resetting ideal_next_packet_send_time_ in pacing sender.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_donot_reset_ideal_next_packet_send_time,
     false)

 // When true and the BBR9 connection option is present, BBR only considers
 // bandwidth samples app-limited if they're not filling the pipe.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr_flexible_app_limited, false)

 // When the STMP connection option is sent by the client, timestamps in the QUIC
 // ACK frame are sent and processed.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_send_timestamps, false)

 // When in STARTUP and recovery, do not add bytes_acked to QUIC BBR's CWND in
 // CalculateCongestionWindow()
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_bbr_no_bytes_acked_in_startup_recovery,
     false)

 // If true and using Leto for QUIC shared-key calculations, GFE will react to a
 // failure to contact Leto by sending a REJ containing a fallback ServerConfig,
 // allowing the client to continue the handshake.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_send_quic_fallback_server_config_on_leto_error,
     false)

 // If true, GFE will not request private keys when fetching QUIC ServerConfigs
 // from Leto.
 QUIC_FLAG(bool,
           FLAGS_quic_restart_flag_dont_fetch_quic_private_keys_from_leto,
           false)

 // In v44 and above, where STOP_WAITING is never sent, close the connection if
 // it's received.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_do_not_accept_stop_waiting,
           false)

 // If true, set burst token to 2 in cwnd bootstrapping experiment.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_conservative_bursts, false)

 // If true, export number of packets written per write operation histogram.")
 QUIC_FLAG(bool, FLAGS_quic_export_server_num_packets_per_write_histogram, false)

 // If true, uses conservative cwnd gain and pacing gain.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_conservative_cwnd_and_pacing_gains,
           false)

 // If true, use predictable version negotiation versions.
 QUIC_FLAG(bool, FLAGS_quic_disable_version_negotiation_grease_randomness, false)

 // Maximum number of tracked packets.
 QUIC_FLAG(int64_t, FLAGS_quic_max_tracked_packet_count, 10000)

 // If true, HTTP request header names sent from QuicSpdyClientBase(and
 // descendents) will be automatically converted to lower case.
 QUIC_FLAG(bool, FLAGS_quic_client_convert_http_header_name_to_lowercase, true)

 // If true, allow client to enable BBRv2 on server via connection option 'B2ON'.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_allow_client_enabled_bbr_v2,
           false)

 // If true, QuicFramer::WriteClientVersionNegotiationProbePacket uses
 // length-prefixed connection IDs.
 QUIC_FLAG(bool, FLAGS_quic_prober_uses_length_prefixed_connection_ids, false)

 // The maximum amount of CRYPTO frame data that can be buffered.
 QUIC_FLAG(int32_t, FLAGS_quic_max_buffered_crypto_bytes, 16 * 1024)

 // If the bandwidth during ack aggregation is smaller than (estimated
 // bandwidth * this flag), consider the current aggregation completed
 // and starts a new one.
 QUIC_FLAG(double, FLAGS_quic_ack_aggregation_bandwidth_threshold, 1.0)

 // If set to non-zero, the maximum number of consecutive pings that can be sent
 // with aggressive initial retransmittable on wire timeout if there is no new
 // data received. After which, the timeout will be exponentially back off until
 // exceeds the default ping timeout.
 QUIC_FLAG(int32_t,
           FLAGS_quic_max_aggressive_retransmittable_on_wire_ping_count,
           0)

 // If true, re-calculate pacing rate when cwnd gets bootstrapped.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr_fix_pacing_rate, true)

 // The maximum congestion window in packets.
 QUIC_FLAG(int32_t, FLAGS_quic_max_congestion_window, 2000)

 // If true, do not inject bandwidth in BbrSender::AdjustNetworkParameters.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_bbr_donot_inject_bandwidth,
           true)

 // The default minimum duration for BBRv2-native probes, in milliseconds.
 QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_bw_base_duration_ms, 2000)

 // The default upper bound of the random amount of BBRv2-native
 // probes, in milliseconds.
 QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_bw_max_rand_duration_ms, 1000)

 // The default period for entering PROBE_RTT, in milliseconds.
 QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_rtt_period_ms, 10000)

 // The default loss threshold for QUIC BBRv2, should be a value
 // between 0 and 1.
 QUIC_FLAG(double, FLAGS_quic_bbr2_default_loss_threshold, 0.02)

 // The default minimum number of loss marking events to exit STARTUP.
 QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_startup_full_loss_count, 8)

 // The default fraction of unutilized headroom to try to leave in path
 // upon high loss.
 QUIC_FLAG(double, FLAGS_quic_bbr2_default_inflight_hi_headroom, 0.01)

 // If true, disable QUIC version Q043.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q043, false)

 // If true, disable QUIC version Q046.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q046, false)

 // If true, disable QUIC version Q048.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q048, true)

 // If true, disable QUIC version Q049.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q049, true)

 // If true, disable QUIC version Q050.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q050, false)

 // A testonly reloadable flag that will always default to false.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_testonly_default_false, false)

 // In BBR, slow pacing rate if it is likely causing overshoot.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_bbr_mitigate_overly_large_bandwidth_sample,
     true)

 // The default initial value of the max ack height filter's window length.
 QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_initial_ack_height_filter_window, 10)

 // The default minimum number of loss marking events to exit PROBE_UP phase.
 QUIC_FLAG(double, FLAGS_quic_bbr2_default_probe_bw_full_loss_count, 2)

 // When true, ensure the ACK delay is never less than the alarm granularity when
 // ACK decimation is enabled.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_ack_delay_alarm_granularity,
           false)

 // If true, use predictable grease settings identifiers and values.
 QUIC_FLAG(bool, FLAGS_quic_enable_http3_grease_randomness, true)

 // If true, disable QUIC version h3-25.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_25, false)

 // If true, disable QUIC version h3-27.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_27, false)

 // If true, QUIC BBRv2 to take ack height into account when calculating
 // queuing_threshold in PROBE_UP.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_bbr2_add_ack_height_to_queueing_threshold,
     true)

 // If true, use idle network detector to detect handshake timeout and idle
 // network timeout.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_use_idle_network_detector, true)

 // If true, QUIC will enable connection options LRTT+BBQ2 by default.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_bbr_default_exit_startup_on_loss,
           true)

 // If true, server push will be allowed in QUIC versions using HTTP/3.
 QUIC_FLAG(bool, FLAGS_quic_enable_http3_server_push, false)

 // The divisor that controls how often MAX_STREAMS frames are sent.
 QUIC_FLAG(int32_t, FLAGS_quic_max_streams_window_divisor, 2)

 // If true, QUIC BBRv2\'s PROBE_BW mode will not reduce cwnd below
 // BDP+ack_height.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_bbr2_avoid_too_low_probe_bw_cwnd,
           false)

 // When true, the 1RTT and 2RTT connection options decrease the number of round
 // trips in BBRv2 STARTUP without a 25% bandwidth increase to 1 or 2 round trips
 // respectively.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_bbr2_fewer_startup_round_trips,
           false)

 // Replace the usage of ConnectionData::encryption_level in
 // quic_time_wait_list_manager with a new TimeWaitAction.
 QUIC_FLAG(bool,
           FLAGS_quic_restart_flag_quic_replace_time_wait_list_encryption_level,
           true)

 // If true, enables support for TLS resumption in QUIC.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_tls_resumption, false)

 // When true, QUIC's BBRv2 ignores inflight_lo in PROBE_BW.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr2_ignore_inflight_lo, false)

 // If true, do not change ACK in PostProcessAckFrame if an ACK has been queued.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_donot_change_queued_ack, true)

 // If true, reject IETF QUIC connections with invalid SNI.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_tls_enforce_valid_sni, true)

 // If true, update ack timeout upon receiving an retransmittable frame.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_advance_ack_timeout_update,
           true)

 // If true, only extend idle time on decryptable packets.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_extend_idle_time_on_decryptable_packets,
     true)

 // If true, support for IETF QUIC 0-rtt is enabled.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_zero_rtt_for_tls, false)

 // If true, default on PTO which unifies TLP + RTO loss recovery.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_on_pto, false)

 // When true, QUIC+TLS will not send nor parse the old-format Google-specific
 // transport parameters.
 QUIC_FLAG(bool,
           FLAGS_quic_restart_flag_quic_google_transport_param_omit_old,
           false)

 // When true, QUIC+TLS will send and parse the new-format Google-specific
 // transport parameters.
 QUIC_FLAG(bool,
           FLAGS_quic_restart_flag_quic_google_transport_param_send_new,
           true)

 // If true, check ShouldGeneratePacket for every crypto packet.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_checking_should_generate_packet,
           true)

 // If true, notify stream ID manager even connection disconnects.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_notify_stream_id_manager_when_disconnected,
     true)

 // If true, return from QuicCryptoStream::WritePendingCryptoRetransmission after
 // partial writes.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_fix_write_pending_crypto_retransmission,
     true)

 // If true, clear last_inflight_packets_sent_time_ of a packet number space when
 // there is no bytes in flight.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_last_inflight_packets_sent_time,
           true)

 // If true, QUIC will free writer-allocated packet buffer if writer->WritePacket
 // is not called.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_avoid_leak_writer_buffer, false)

 // If true, QuicConnection::SendAllPendingAcks will Update instead of Set the
 // ack alarm.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_update_ack_alarm_in_send_all_pending_acks,
     true)

 // If true, enable QUIC version h3-28.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_version_draft_28, true)

 // If true, the B2HI connection option limits reduction of inflight_hi to
 // (1-Beta)*CWND.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr2_limit_inflight_hi, false)

 // When true, always check the amplification limit before writing, not just for
 // handshake packets.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_move_amplification_limit, true)

 // If true, SendAllPendingAcks always send the earliest ACK.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_always_send_earliest_ack, false)

 // If true, check connection level flow control for send control stream and
 // qpack streams in QuicSession::WillingAndAbleToWrite.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_willing_and_able_to_write,
           true)

 // If true, disable QUIC version h3-T050.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_t050, false)

 // If true, do not arm PTO on half RTT packets if they are the only ones in
 // flight.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_fix_server_pto_timeout, true)

 // If true, default-enable 5RTO blachole detection.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_default_enable_5rto_blackhole_detection2,
     true)

 // If true, session does not send duplicate MAX_STREAMS.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_stop_sending_duplicate_max_streams,
           false)

 // If true, enable QUIC version h3-29.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_version_draft_29, true)

 // If true, support HANDSHAKE_DONE frame in T050
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_support_handshake_done_in_t050,
           true)

 // If true, save user agent into in QuicSession.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_save_user_agent_in_quic_session,
           false)

 // When true, QUIC_CRYPTO versions of QUIC will not send the max ACK delay
 // unless it is configured to a non-default value.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_dont_send_max_ack_delay_if_default,
           true)
	// Copyright 2014 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.

	// This file intentionally does not have header guards, it's included
	// inside a macro to generate values. The following line silences a
	// presubmit warning that would otherwise be triggered by this:
	// no-include-guard-because-multiply-included
	// NOLINT(build/header_guard)

	// This file contains the list of QUIC protocol flags.

	// Time period for which a given connection_id should live in the time-wait
	// state.
	QUIC_FLAG(int64_t, FLAGS_quic_time_wait_list_seconds, 200)

	// Currently, this number is quite conservative. The max QPS limit for an
	// individual server silo is currently set to 1000 qps, though the actual max
	// that we see in the wild is closer to 450 qps. Regardless, this means that
	// the longest time-wait list we should see is 200 seconds * 1000 qps, 200000.
	// Of course, there are usually many queries per QUIC connection, so we allow a
	// factor of 3 leeway.
	//
	// Maximum number of connections on the time-wait list. A negative value implies
	// no configured limit.
	QUIC_FLAG(int64_t, FLAGS_quic_time_wait_list_max_connections, 600000)

	// If true, require handshake confirmation for QUIC connections, functionally
	// disabling 0-rtt handshakes.
	// TODO(rtenneti): Enable this flag after CryptoServerTest's are fixed.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_require_handshake_confirmation,
	false)

	// If true, disable pacing in QUIC.
	QUIC_FLAG(bool, FLAGS_quic_disable_pacing_for_perf_tests, false)

	// If true, enforce that QUIC CHLOs fit in one packet.
	QUIC_FLAG(bool, FLAGS_quic_enforce_single_packet_chlo, true)

	// If true, allows packets to be buffered in anticipation of a future CHLO, and
	// allow CHLO packets to be buffered until next iteration of the event loop.
	QUIC_FLAG(bool, FLAGS_quic_allow_chlo_buffering, true)

	// If greater than zero, mean RTT variation is multiplied by the specified
	// factor and added to the congestion window limit.
	QUIC_FLAG(double, FLAGS_quic_bbr_rtt_variation_weight, 0.0f)

	// Congestion window gain for QUIC BBR during PROBE_BW phase.
	QUIC_FLAG(double, FLAGS_quic_bbr_cwnd_gain, 2.0f)

	// If true, adjust congestion window when doing bandwidth resumption in BBR.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_bbr_cwnd_in_bandwidth_resumption,
	true)

	// When true, defaults to BBR congestion control instead of Cubic.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_to_bbr, false)

	// If true, use BBRv2 as the default congestion controller.
	// Takes precedence over --quic_default_to_bbr.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_to_bbr_v2, false)

	// If buffered data in QUIC stream is less than this threshold, buffers all
	// provided data or asks upper layer for more data.
	QUIC_FLAG(uint32_t, FLAGS_quic_buffered_data_threshold, 8192u)

	// Max size of data slice in bytes for QUIC stream send buffer.
	QUIC_FLAG(uint32_t, FLAGS_quic_send_buffer_max_data_slice_size, 4096u)

	// Anti-amplification factor. Before address validation, server will
	// send no more than factor times bytes received.
	QUIC_FLAG(int32_t, FLAGS_quic_anti_amplification_factor, 3)

	// When true, set the initial congestion control window from connection options
	// in QuicSentPacketManager rather than TcpCubicSenderBytes.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_unified_iw_options, false)

	// Number of packets that the pacing sender allows in bursts during pacing.
	QUIC_FLAG(int32_t, FLAGS_quic_lumpy_pacing_size, 2)

	// Congestion window fraction that the pacing sender allows in bursts during
	// pacing.
	QUIC_FLAG(double, FLAGS_quic_lumpy_pacing_cwnd_fraction, 0.25f)

	// Default enables QUIC ack decimation and adds a connection option to disable
	// it.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_ack_decimation, true)

	// If true, QUIC offload pacing when using USPS as egress method.
	QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_offload_pacing_to_usps2, false)

	// Max time that QUIC can pace packets into the future in ms.
	QUIC_FLAG(int32_t, FLAGS_quic_max_pace_time_into_future_ms, 10)

	// Smoothed RTT fraction that a connection can pace packets into the future.
	QUIC_FLAG(double, FLAGS_quic_pace_time_into_future_srtt_fraction, 0.125f)

	// Mechanism to override version label and ALPN for IETF interop.
	QUIC_FLAG(int32_t, FLAGS_quic_ietf_draft_version, 0)

	// If true, stop resetting ideal_next_packet_send_time_ in pacing sender.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_donot_reset_ideal_next_packet_send_time,
	false)

	// When true and the BBR9 connection option is present, BBR only considers
	// bandwidth samples app-limited if they're not filling the pipe.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr_flexible_app_limited, false)

	// When the STMP connection option is sent by the client, timestamps in the QUIC
	// ACK frame are sent and processed.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_send_timestamps, false)

	// When in STARTUP and recovery, do not add bytes_acked to QUIC BBR's CWND in
	// CalculateCongestionWindow()
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_bbr_no_bytes_acked_in_startup_recovery,
	false)

	// If true and using Leto for QUIC shared-key calculations, GFE will react to a
	// failure to contact Leto by sending a REJ containing a fallback ServerConfig,
	// allowing the client to continue the handshake.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_send_quic_fallback_server_config_on_leto_error,
	false)

	// If true, GFE will not request private keys when fetching QUIC ServerConfigs
	// from Leto.
	QUIC_FLAG(bool,
	FLAGS_quic_restart_flag_dont_fetch_quic_private_keys_from_leto,
	false)

	// In v44 and above, where STOP_WAITING is never sent, close the connection if
	// it's received.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_do_not_accept_stop_waiting,
	false)

	// If true, set burst token to 2 in cwnd bootstrapping experiment.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_conservative_bursts, false)

	// If true, export number of packets written per write operation histogram.")
	QUIC_FLAG(bool, FLAGS_quic_export_server_num_packets_per_write_histogram, false)

	// If true, uses conservative cwnd gain and pacing gain.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_conservative_cwnd_and_pacing_gains,
	false)

	// If true, use predictable version negotiation versions.
	QUIC_FLAG(bool, FLAGS_quic_disable_version_negotiation_grease_randomness, false)

	// Maximum number of tracked packets.
	QUIC_FLAG(int64_t, FLAGS_quic_max_tracked_packet_count, 10000)

	// If true, HTTP request header names sent from QuicSpdyClientBase(and
	// descendents) will be automatically converted to lower case.
	QUIC_FLAG(bool, FLAGS_quic_client_convert_http_header_name_to_lowercase, true)

	// If true, allow client to enable BBRv2 on server via connection option 'B2ON'.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_allow_client_enabled_bbr_v2,
	false)

	// If true, QuicFramer::WriteClientVersionNegotiationProbePacket uses
	// length-prefixed connection IDs.
	QUIC_FLAG(bool, FLAGS_quic_prober_uses_length_prefixed_connection_ids, false)

	// The maximum amount of CRYPTO frame data that can be buffered.
	QUIC_FLAG(int32_t, FLAGS_quic_max_buffered_crypto_bytes, 16 * 1024)

	// If the bandwidth during ack aggregation is smaller than (estimated
	// bandwidth * this flag), consider the current aggregation completed
	// and starts a new one.
	QUIC_FLAG(double, FLAGS_quic_ack_aggregation_bandwidth_threshold, 1.0)

	// If set to non-zero, the maximum number of consecutive pings that can be sent
	// with aggressive initial retransmittable on wire timeout if there is no new
	// data received. After which, the timeout will be exponentially back off until
	// exceeds the default ping timeout.
	QUIC_FLAG(int32_t,
	FLAGS_quic_max_aggressive_retransmittable_on_wire_ping_count,
	0)

	// If true, re-calculate pacing rate when cwnd gets bootstrapped.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr_fix_pacing_rate, true)

	// The maximum congestion window in packets.
	QUIC_FLAG(int32_t, FLAGS_quic_max_congestion_window, 2000)

	// If true, do not inject bandwidth in BbrSender::AdjustNetworkParameters.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_bbr_donot_inject_bandwidth,
	true)

	// The default minimum duration for BBRv2-native probes, in milliseconds.
	QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_bw_base_duration_ms, 2000)

	// The default upper bound of the random amount of BBRv2-native
	// probes, in milliseconds.
	QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_bw_max_rand_duration_ms, 1000)

	// The default period for entering PROBE_RTT, in milliseconds.
	QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_rtt_period_ms, 10000)

	// The default loss threshold for QUIC BBRv2, should be a value
	// between 0 and 1.
	QUIC_FLAG(double, FLAGS_quic_bbr2_default_loss_threshold, 0.02)

	// The default minimum number of loss marking events to exit STARTUP.
	QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_startup_full_loss_count, 8)

	// The default fraction of unutilized headroom to try to leave in path
	// upon high loss.
	QUIC_FLAG(double, FLAGS_quic_bbr2_default_inflight_hi_headroom, 0.01)

	// If true, disable QUIC version Q043.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q043, false)

	// If true, disable QUIC version Q046.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q046, false)

	// If true, disable QUIC version Q048.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q048, true)

	// If true, disable QUIC version Q049.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q049, true)

	// If true, disable QUIC version Q050.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_q050, false)

	// A testonly reloadable flag that will always default to false.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_testonly_default_false, false)

	// In BBR, slow pacing rate if it is likely causing overshoot.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_bbr_mitigate_overly_large_bandwidth_sample,
	true)

	// The default initial value of the max ack height filter's window length.
	QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_initial_ack_height_filter_window, 10)

	// The default minimum number of loss marking events to exit PROBE_UP phase.
	QUIC_FLAG(double, FLAGS_quic_bbr2_default_probe_bw_full_loss_count, 2)

	// When true, ensure the ACK delay is never less than the alarm granularity when
	// ACK decimation is enabled.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_ack_delay_alarm_granularity,
	false)

	// If true, use predictable grease settings identifiers and values.
	QUIC_FLAG(bool, FLAGS_quic_enable_http3_grease_randomness, true)

	// If true, disable QUIC version h3-25.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_25, false)

	// If true, disable QUIC version h3-27.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_27, false)

	// If true, QUIC BBRv2 to take ack height into account when calculating
	// queuing_threshold in PROBE_UP.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_bbr2_add_ack_height_to_queueing_threshold,
	true)

	// If true, use idle network detector to detect handshake timeout and idle
	// network timeout.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_use_idle_network_detector, true)

	// If true, QUIC will enable connection options LRTT+BBQ2 by default.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_bbr_default_exit_startup_on_loss,
	true)

	// If true, server push will be allowed in QUIC versions using HTTP/3.
	QUIC_FLAG(bool, FLAGS_quic_enable_http3_server_push, false)

	// The divisor that controls how often MAX_STREAMS frames are sent.
	QUIC_FLAG(int32_t, FLAGS_quic_max_streams_window_divisor, 2)

	// If true, QUIC BBRv2\'s PROBE_BW mode will not reduce cwnd below
	// BDP+ack_height.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_bbr2_avoid_too_low_probe_bw_cwnd,
	false)

	// When true, the 1RTT and 2RTT connection options decrease the number of round
	// trips in BBRv2 STARTUP without a 25% bandwidth increase to 1 or 2 round trips
	// respectively.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_bbr2_fewer_startup_round_trips,
	false)

	// Replace the usage of ConnectionData::encryption_level in
	// quic_time_wait_list_manager with a new TimeWaitAction.
	QUIC_FLAG(bool,
	FLAGS_quic_restart_flag_quic_replace_time_wait_list_encryption_level,
	true)

	// If true, enables support for TLS resumption in QUIC.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_tls_resumption, false)

	// When true, QUIC's BBRv2 ignores inflight_lo in PROBE_BW.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr2_ignore_inflight_lo, false)

	// If true, do not change ACK in PostProcessAckFrame if an ACK has been queued.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_donot_change_queued_ack, true)

	// If true, reject IETF QUIC connections with invalid SNI.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_tls_enforce_valid_sni, true)

	// If true, update ack timeout upon receiving an retransmittable frame.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_advance_ack_timeout_update,
	true)

	// If true, only extend idle time on decryptable packets.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_extend_idle_time_on_decryptable_packets,
	true)

	// If true, support for IETF QUIC 0-rtt is enabled.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_zero_rtt_for_tls, false)

	// If true, default on PTO which unifies TLP + RTO loss recovery.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_on_pto, false)

	// When true, QUIC+TLS will not send nor parse the old-format Google-specific
	// transport parameters.
	QUIC_FLAG(bool,
	FLAGS_quic_restart_flag_quic_google_transport_param_omit_old,
	false)

	// When true, QUIC+TLS will send and parse the new-format Google-specific
	// transport parameters.
	QUIC_FLAG(bool,
	FLAGS_quic_restart_flag_quic_google_transport_param_send_new,
	true)

	// If true, check ShouldGeneratePacket for every crypto packet.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_checking_should_generate_packet,
	true)

	// If true, notify stream ID manager even connection disconnects.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_notify_stream_id_manager_when_disconnected,
	true)

	// If true, return from QuicCryptoStream::WritePendingCryptoRetransmission after
	// partial writes.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_fix_write_pending_crypto_retransmission,
	true)

	// If true, clear last_inflight_packets_sent_time_ of a packet number space when
	// there is no bytes in flight.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_last_inflight_packets_sent_time,
	true)

	// If true, QUIC will free writer-allocated packet buffer if writer->WritePacket
	// is not called.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_avoid_leak_writer_buffer, false)

	// If true, QuicConnection::SendAllPendingAcks will Update instead of Set the
	// ack alarm.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_update_ack_alarm_in_send_all_pending_acks,
	true)

	// If true, enable QUIC version h3-28.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_version_draft_28, true)

	// If true, the B2HI connection option limits reduction of inflight_hi to
	// (1-Beta)*CWND.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_bbr2_limit_inflight_hi, false)

	// When true, always check the amplification limit before writing, not just for
	// handshake packets.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_move_amplification_limit, true)

	// If true, SendAllPendingAcks always send the earliest ACK.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_always_send_earliest_ack, false)

	// If true, check connection level flow control for send control stream and
	// qpack streams in QuicSession::WillingAndAbleToWrite.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_willing_and_able_to_write,
	true)

	// If true, disable QUIC version h3-T050.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_t050, false)

	// If true, do not arm PTO on half RTT packets if they are the only ones in
	// flight.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_fix_server_pto_timeout, true)

	// If true, default-enable 5RTO blachole detection.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_default_enable_5rto_blackhole_detection2,
	true)

	// If true, session does not send duplicate MAX_STREAMS.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_stop_sending_duplicate_max_streams,
	false)

	// If true, enable QUIC version h3-29.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_enable_version_draft_29, true)

	// If true, support HANDSHAKE_DONE frame in T050
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_support_handshake_done_in_t050,
	true)

	// If true, save user agent into in QuicSession.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_save_user_agent_in_quic_session,
	false)

	// When true, QUIC_CRYPTO versions of QUIC will not send the max ACK delay
	// unless it is configured to a non-default value.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_dont_send_max_ack_delay_if_default,
	true)