net/quic/quic_flags_list.h - chromium/src.git - 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)

 // 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)

 // 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 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)

 // 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)

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

 // 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 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)

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

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

 // A testonly restart flag that will always default to true.
 QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_testonly_default_true, 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 h3-27.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_27, false)

 // 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)

 // If true, support for IETF QUIC 0-rtt is enabled.
 QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_enable_zero_rtt_for_tls_v2, true)

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

 // 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)

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

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

 // If true, disable QUIC version h3-29.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_29, false)

 // If true, record the received min_ack_delay in transport parameters to QUIC
 // config.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_record_received_min_ack_delay,
           false)

 // If true, disable blackhole detection on server side.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_disable_server_blackhole_detection,
           false)

 // When true, QUIC+TLS versions will send the key_update_not_yet_supported
 // transport parameter.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_send_key_update_not_yet_supported,
           true)

 // If true, QUIC will default enable MTU discovery, with a target of 1450 bytes.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_enable_mtu_discovery_at_server,
           false)

 // If true, while reading an IETF quic packet, start peer migration immediately
 // when detecting the existence of any non-probing frame instead of at the end
 // of the packet.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_start_peer_migration_earlier,
           false)

 // If true, neuter initial packet in the coalescer when discarding initial keys.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_neuter_initial_packet_in_coalescer_with_initial_key_discarded,
     true)

 // If true, convert bytes_left_for_batch_write_ to unsigned int.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_bytes_left_for_batch_write,
           true)

 // If true, add missing connected checks.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_add_missing_connected_checks,
           true)

 // If true, QuicStream::kDefaultUrgency is 3, otherwise 1.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_http3_new_default_urgency_value,
           false)

 // If true, close connection on packet serialization failures
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_close_connection_on_serialization_failure,
     true)

 // If true, send PATH_RESPONSE upon receiving PATH_CHALLENGE regardless
 // of perspective.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_send_path_response, false)

 // If true, when switching from BBR to BBR2, use BBR's CWND as the initial CWND.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_copy_bbr_cwnd_to_bbr2, true)

 // If true, send the lowest stream ID that can be retried by the client in a
 // GOAWAY frame.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_http3_goaway_stream_id,
           false)

 // If true, close connection if writer is still blocked when OnCanWrite is
 // called.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_close_connection_in_on_can_write_with_blocked_writer,
     true)

 // If true, include stream information in idle timeout connection close detail.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_add_stream_info_to_idle_close_detail,
           true)

 // If true, use IETF QUIC application error codes in STOP_SENDING frames.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_stop_sending_uses_ietf_error_code,
           true)

 // If true, QuicSpdySession's destructor won't need to do cleanup.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_clean_up_spdy_session_destructor,
           true)

 // If true, discard INITIAL packet if the key has been dropped.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_discard_initial_packet_with_key_dropped,
     true)

 // If true, disable QUIC version h3-T051.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_t051, false)

 // If true, make sure there is pending timer credit when trying to PTO
 // retransmit any packets.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_pto_pending_timer_count,
           true)

 // If true, QUIC connection will pass sent packet information to the debug
 // visitor after a packet is recorded as sent in sent packet manager.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_give_sent_packet_to_debug_visitor_after_sent,
     true)

 // If true, abort async QPACK header decompression in QuicSpdyStream::OnClose().
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_abort_qpack_on_stream_close,
           false)

 // If true, do not arm PTO for application data until handshake confirmed.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_arm_pto_for_application_data,
           true)

 // If true, cap client suggested initial RTT to 1s if it is longer than 1s.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_cap_large_client_initial_rtt,
           true)

 // If true, fix a potential out of order sending caused by handshake gets
 // confirmed while the coalescer is not empty.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_fix_out_of_order_sending2, true)

 // If true, remove processed undecryptable packets.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_undecryptable_packets2,
           true)

 // If true, QUIC BBRv2 will use inflight byte after congestion event to detect
 // queuing during PROBE_UP.
 QUIC_FLAG(
     bool,
     FLAGS_quic_reloadable_flag_quic_bbr2_use_post_inflight_to_detect_queuing,
     false)

 // If true, QUIC BBRv2 will use 15% inflight_hi headroom, which is the default
 // for TCP.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_bbr2_use_tcp_inflight_hi_headroom,
           false)

 // If true, HTTP/3 will treat HTTP/2 specific SETTINGS as error.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_reject_spdy_settings, false)

 // If true, discard 0-RTT keys after installing 1-RTT keys on the client side.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_postpone_discarding_zero_rtt_keys,
           true)

 // If true, for IETF QUIC, uses 2 * RTTVAR when calculating PTO delay.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_to_2_rttvar, true)

 // Deallocate data in QuicMessageFrame right after the corresponding packet is
 // sent.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_deallocate_message_right_after_sent,
           false)

 // If true, drop initial keys at the end of writing and unify the fixes for
 // missing initial keys.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_fix_missing_initial_keys2, true)

 // If true, check whether framer has the right key before writing data.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_check_keys_before_writing, true)

 // If true, received error codes larger than QUIC_LAST_ERROR are preserved.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_do_not_clip_received_error_code,
           false)

 // If true, check for NULL before sending a fallback config.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_check_fallback_null, true)

 // If true, HTTP/3 sesions will report error and close connection upon receiving
 // HTTP/2 only frames.
 QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_reject_spdy_frames, false)

 // If true, QuicConnection will initialize its self address to the self address
 // of the first received packet, for all server connections and client
 // connections that know its own address.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_connection_set_initial_self_address,
           false)

 // If true, let QUIC connection handle PINGs instead of going through session.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_let_connection_handle_pings,
           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)

	// 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)

	// 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 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)

	// 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)

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

	// 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 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)

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

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

	// A testonly restart flag that will always default to true.
	QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_testonly_default_true, 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 h3-27.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_27, false)

	// 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)

	// If true, support for IETF QUIC 0-rtt is enabled.
	QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_enable_zero_rtt_for_tls_v2, true)

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

	// 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)

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

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

	// If true, disable QUIC version h3-29.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_draft_29, false)

	// If true, record the received min_ack_delay in transport parameters to QUIC
	// config.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_record_received_min_ack_delay,
	false)

	// If true, disable blackhole detection on server side.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_disable_server_blackhole_detection,
	false)

	// When true, QUIC+TLS versions will send the key_update_not_yet_supported
	// transport parameter.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_send_key_update_not_yet_supported,
	true)

	// If true, QUIC will default enable MTU discovery, with a target of 1450 bytes.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_enable_mtu_discovery_at_server,
	false)

	// If true, while reading an IETF quic packet, start peer migration immediately
	// when detecting the existence of any non-probing frame instead of at the end
	// of the packet.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_start_peer_migration_earlier,
	false)

	// If true, neuter initial packet in the coalescer when discarding initial keys.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_neuter_initial_packet_in_coalescer_with_initial_key_discarded,
	true)

	// If true, convert bytes_left_for_batch_write_ to unsigned int.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_bytes_left_for_batch_write,
	true)

	// If true, add missing connected checks.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_add_missing_connected_checks,
	true)

	// If true, QuicStream::kDefaultUrgency is 3, otherwise 1.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_http3_new_default_urgency_value,
	false)

	// If true, close connection on packet serialization failures
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_close_connection_on_serialization_failure,
	true)

	// If true, send PATH_RESPONSE upon receiving PATH_CHALLENGE regardless
	// of perspective.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_send_path_response, false)

	// If true, when switching from BBR to BBR2, use BBR's CWND as the initial CWND.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_copy_bbr_cwnd_to_bbr2, true)

	// If true, send the lowest stream ID that can be retried by the client in a
	// GOAWAY frame.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_http3_goaway_stream_id,
	false)

	// If true, close connection if writer is still blocked when OnCanWrite is
	// called.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_close_connection_in_on_can_write_with_blocked_writer,
	true)

	// If true, include stream information in idle timeout connection close detail.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_add_stream_info_to_idle_close_detail,
	true)

	// If true, use IETF QUIC application error codes in STOP_SENDING frames.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_stop_sending_uses_ietf_error_code,
	true)

	// If true, QuicSpdySession's destructor won't need to do cleanup.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_clean_up_spdy_session_destructor,
	true)

	// If true, discard INITIAL packet if the key has been dropped.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_discard_initial_packet_with_key_dropped,
	true)

	// If true, disable QUIC version h3-T051.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_disable_version_t051, false)

	// If true, make sure there is pending timer credit when trying to PTO
	// retransmit any packets.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_pto_pending_timer_count,
	true)

	// If true, QUIC connection will pass sent packet information to the debug
	// visitor after a packet is recorded as sent in sent packet manager.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_give_sent_packet_to_debug_visitor_after_sent,
	true)

	// If true, abort async QPACK header decompression in QuicSpdyStream::OnClose().
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_abort_qpack_on_stream_close,
	false)

	// If true, do not arm PTO for application data until handshake confirmed.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_arm_pto_for_application_data,
	true)

	// If true, cap client suggested initial RTT to 1s if it is longer than 1s.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_cap_large_client_initial_rtt,
	true)

	// If true, fix a potential out of order sending caused by handshake gets
	// confirmed while the coalescer is not empty.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_fix_out_of_order_sending2, true)

	// If true, remove processed undecryptable packets.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_fix_undecryptable_packets2,
	true)

	// If true, QUIC BBRv2 will use inflight byte after congestion event to detect
	// queuing during PROBE_UP.
	QUIC_FLAG(
	bool,
	FLAGS_quic_reloadable_flag_quic_bbr2_use_post_inflight_to_detect_queuing,
	false)

	// If true, QUIC BBRv2 will use 15% inflight_hi headroom, which is the default
	// for TCP.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_bbr2_use_tcp_inflight_hi_headroom,
	false)

	// If true, HTTP/3 will treat HTTP/2 specific SETTINGS as error.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_reject_spdy_settings, false)

	// If true, discard 0-RTT keys after installing 1-RTT keys on the client side.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_postpone_discarding_zero_rtt_keys,
	true)

	// If true, for IETF QUIC, uses 2 * RTTVAR when calculating PTO delay.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_default_to_2_rttvar, true)

	// Deallocate data in QuicMessageFrame right after the corresponding packet is
	// sent.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_deallocate_message_right_after_sent,
	false)

	// If true, drop initial keys at the end of writing and unify the fixes for
	// missing initial keys.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_fix_missing_initial_keys2, true)

	// If true, check whether framer has the right key before writing data.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_check_keys_before_writing, true)

	// If true, received error codes larger than QUIC_LAST_ERROR are preserved.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_do_not_clip_received_error_code,
	false)

	// If true, check for NULL before sending a fallback config.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_check_fallback_null, true)

	// If true, HTTP/3 sesions will report error and close connection upon receiving
	// HTTP/2 only frames.
	QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_reject_spdy_frames, false)

	// If true, QuicConnection will initialize its self address to the self address
	// of the first received packet, for all server connections and client
	// connections that know its own address.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_connection_set_initial_self_address,
	false)

	// If true, let QUIC connection handle PINGs instead of going through session.
	QUIC_FLAG(bool,
	FLAGS_quic_reloadable_flag_quic_let_connection_handle_pings,
	true)