net/quic/quic_flags.cc - 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.

 #include "net/quic/quic_flags.h"

 // If true, it will return as soon as an error is detected while validating
 // CHLO.
 bool FLAGS_use_early_return_when_verifying_chlo = true;

 // If true, QUIC BBR congestion control may be enabled via Finch and/or via QUIC
 // connection options.
 bool FLAGS_quic_allow_bbr = false;

 // Time period for which a given connection_id should live in the time-wait
 // state.
 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.
 int64_t FLAGS_quic_time_wait_list_max_connections = 600000;

 // Enables server-side support for QUIC stateless rejects.
 bool FLAGS_enable_quic_stateless_reject_support = true;

 // This flag is not in use, just to keep consistency for shared code.
 bool FLAGS_quic_always_log_bugs_for_tests = true;

 // If true, a QUIC connection option with tag DHDT can be used to disable
 // HPACK\'s dynamic table.
 bool FLAGS_quic_disable_hpack_dynamic_table = true;

 // If true, multipath is enabled for the connection.
 bool FLAGS_quic_enable_multipath = false;

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

 // If true, Cubic's epoch is shifted when the sender is application-limited.
 bool FLAGS_shift_quic_cubic_epoch_when_app_limited = true;

 // If true, QUIC will measure head of line (HOL) blocking due between
 // streams due to packet losses on the headers stream.  The
 // measurements will be surfaced via UMA histogram
 // Net.QuicSession.HeadersHOLBlockedTime.
 bool FLAGS_quic_measure_headers_hol_blocking_time = true;

 // If true, disable pacing in QUIC.
 bool FLAGS_quic_disable_pacing_for_perf_tests = false;

 // If true, Close the connection instead of writing unencrypted stream data.
 bool FLAGS_quic_never_write_unencrypted_data = true;

 // If true, reject any incoming QUIC which does not have the FIXD tag.
 bool FLAGS_quic_require_fix = true;

 // If true, headers stream will support receiving PUSH_PROMISE frames.
 bool FLAGS_quic_supports_push_promise = true;

 // If true, make sure new incoming streams correctly cede to higher
 // priority (or batch) streams when doing QUIC writes.
 bool FLAGS_quic_cede_correctly = true;

 // Resend 0RTT requests in response to an REJ that re-establishes encryption.
 bool FLAGS_quic_reply_to_rej = true;

 // If true, QUIC connections can do bandwidth resumption with an initial window
 // of < 10 packets.
 bool FLAGS_quic_no_lower_bw_resumption_limit = true;

 // Limit the ruction of slow start large reduction to 1/2 the current CWND once
 // the initial flight has been acked.
 bool FLAGS_quic_sslr_limit_reduction = true;

 // If true, flow controller may grow the receive window size if necessary.
 bool FLAGS_quic_auto_tune_receive_window = true;

 // If true, enable auto tuning by default (server side).
 bool FLAGS_quic_enable_autotune_by_default = true;

 // Use largest acked in the most recent ack instead of largest acked ever in
 // loss recovery.
 bool FLAGS_quic_loss_recovery_use_largest_acked = true;

 // Only set one alarm for sending at once, either the send alarm or
 // retransmission alarm.  Disabled because it breaks QUIC time loss detection.
 bool FLAGS_quic_only_one_sending_alarm = false;

 // If true, the hash of the CHLO message will be used in the proof generated for
 // an SCUP message.
 bool FLAGS_quic_use_hash_in_scup = true;

 // If true, QUIC public reset packets will have the \"pre-v33\" public header
 // flags.
 bool FLAGS_quic_use_old_public_reset_packets = true;

 // Ignore the peer's recieve buffer size and instead set max CWND based on the
 // amount of data the sender is willing to have in flight.
 bool FLAGS_quic_ignore_srbf = true;

 // Allow the NPRR connection option which reduces QUIC\'s pacing rate during
 // recovery instead of PRR.
 bool FLAGS_quic_allow_noprr = true;

 // Use a write path optimized for StreamFrames.
 bool FLAGS_quic_use_optimized_write_path = true;

 // If true, the dispatcher is responsible for generating server designated
 // connection IDs.
 bool FLAGS_quic_dispatcher_creates_id = true;

 // If true, checks if the CHLO is acceptable as a matter of policy.
 bool FLAGS_quic_enable_chlo_policy = true;

 // If true, ignore QUIC data frames of length 0 for flow control.
 bool FLAGS_quic_ignore_zero_length_frames = true;

 // If true, replace ServerHelloNotifier with a check to see if a decrypted
 // packet is forward secure.
 bool FLAGS_quic_no_shlo_listener = true;

 // If true, queued retransmission packets, because of write blocked
 // socket, are always sent once the socket gets unblocked
 bool FLAGS_quic_always_write_queued_retransmissions = true;

 // Adds a RATE connection option to do rate based sending.
 bool FLAGS_quic_rate_based_sending = true;

 // If true, QUIC will use cheap stateless rejects without creating a full
 // connection.
 bool FLAGS_quic_use_cheap_stateless_rejects = false;

 // If true, treat timestamps from SO_TIMESTAMPING as QuicWallTimes rather
 // than QuicTimes.
 bool FLAGS_quic_socket_walltimestamps = false;

 // If true, default to immediate forward secure once established on the
 // server side, and the IPFS connection option disables this instead of
 // enabling it.
 bool FLAGS_quic_default_immediate_forward_secure = true;

 // If true, disables support for QUIC version 29 and earlier.
 bool FLAGS_quic_disable_pre_30 = false;

 // If true, QUIC respect HTTP2 SETTINGS frame rather than always close the
 // connection.
 bool FLAGS_quic_respect_http2_settings_frame = true;

 // Do not use a QuicAckListener in order to confirm a larger Path MTU.
 bool FLAGS_quic_no_mtu_discovery_ack_listener = false;

 // Deprecate QuicPacketCreator::next_packet_number_length_ because it's no
 // longer necessary.
 bool FLAGS_quic_simple_packet_number_length = false;

 // If true, enables QUIC_VERSION_35.
 bool FLAGS_quic_enable_version_35 = false;
	// 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.

	#include "net/quic/quic_flags.h"

	// If true, it will return as soon as an error is detected while validating
	// CHLO.
	bool FLAGS_use_early_return_when_verifying_chlo = true;

	// If true, QUIC BBR congestion control may be enabled via Finch and/or via QUIC
	// connection options.
	bool FLAGS_quic_allow_bbr = false;

	// Time period for which a given connection_id should live in the time-wait
	// state.
	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.
	int64_t FLAGS_quic_time_wait_list_max_connections = 600000;

	// Enables server-side support for QUIC stateless rejects.
	bool FLAGS_enable_quic_stateless_reject_support = true;

	// This flag is not in use, just to keep consistency for shared code.
	bool FLAGS_quic_always_log_bugs_for_tests = true;

	// If true, a QUIC connection option with tag DHDT can be used to disable
	// HPACK\'s dynamic table.
	bool FLAGS_quic_disable_hpack_dynamic_table = true;

	// If true, multipath is enabled for the connection.
	bool FLAGS_quic_enable_multipath = false;

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

	// If true, Cubic's epoch is shifted when the sender is application-limited.
	bool FLAGS_shift_quic_cubic_epoch_when_app_limited = true;

	// If true, QUIC will measure head of line (HOL) blocking due between
	// streams due to packet losses on the headers stream. The
	// measurements will be surfaced via UMA histogram
	// Net.QuicSession.HeadersHOLBlockedTime.
	bool FLAGS_quic_measure_headers_hol_blocking_time = true;

	// If true, disable pacing in QUIC.
	bool FLAGS_quic_disable_pacing_for_perf_tests = false;

	// If true, Close the connection instead of writing unencrypted stream data.
	bool FLAGS_quic_never_write_unencrypted_data = true;

	// If true, reject any incoming QUIC which does not have the FIXD tag.
	bool FLAGS_quic_require_fix = true;

	// If true, headers stream will support receiving PUSH_PROMISE frames.
	bool FLAGS_quic_supports_push_promise = true;

	// If true, make sure new incoming streams correctly cede to higher
	// priority (or batch) streams when doing QUIC writes.
	bool FLAGS_quic_cede_correctly = true;

	// Resend 0RTT requests in response to an REJ that re-establishes encryption.
	bool FLAGS_quic_reply_to_rej = true;

	// If true, QUIC connections can do bandwidth resumption with an initial window
	// of < 10 packets.
	bool FLAGS_quic_no_lower_bw_resumption_limit = true;

	// Limit the ruction of slow start large reduction to 1/2 the current CWND once
	// the initial flight has been acked.
	bool FLAGS_quic_sslr_limit_reduction = true;

	// If true, flow controller may grow the receive window size if necessary.
	bool FLAGS_quic_auto_tune_receive_window = true;

	// If true, enable auto tuning by default (server side).
	bool FLAGS_quic_enable_autotune_by_default = true;

	// Use largest acked in the most recent ack instead of largest acked ever in
	// loss recovery.
	bool FLAGS_quic_loss_recovery_use_largest_acked = true;

	// Only set one alarm for sending at once, either the send alarm or
	// retransmission alarm. Disabled because it breaks QUIC time loss detection.
	bool FLAGS_quic_only_one_sending_alarm = false;

	// If true, the hash of the CHLO message will be used in the proof generated for
	// an SCUP message.
	bool FLAGS_quic_use_hash_in_scup = true;

	// If true, QUIC public reset packets will have the \"pre-v33\" public header
	// flags.
	bool FLAGS_quic_use_old_public_reset_packets = true;

	// Ignore the peer's recieve buffer size and instead set max CWND based on the
	// amount of data the sender is willing to have in flight.
	bool FLAGS_quic_ignore_srbf = true;

	// Allow the NPRR connection option which reduces QUIC\'s pacing rate during
	// recovery instead of PRR.
	bool FLAGS_quic_allow_noprr = true;

	// Use a write path optimized for StreamFrames.
	bool FLAGS_quic_use_optimized_write_path = true;

	// If true, the dispatcher is responsible for generating server designated
	// connection IDs.
	bool FLAGS_quic_dispatcher_creates_id = true;

	// If true, checks if the CHLO is acceptable as a matter of policy.
	bool FLAGS_quic_enable_chlo_policy = true;

	// If true, ignore QUIC data frames of length 0 for flow control.
	bool FLAGS_quic_ignore_zero_length_frames = true;

	// If true, replace ServerHelloNotifier with a check to see if a decrypted
	// packet is forward secure.
	bool FLAGS_quic_no_shlo_listener = true;

	// If true, queued retransmission packets, because of write blocked
	// socket, are always sent once the socket gets unblocked
	bool FLAGS_quic_always_write_queued_retransmissions = true;

	// Adds a RATE connection option to do rate based sending.
	bool FLAGS_quic_rate_based_sending = true;

	// If true, QUIC will use cheap stateless rejects without creating a full
	// connection.
	bool FLAGS_quic_use_cheap_stateless_rejects = false;

	// If true, treat timestamps from SO_TIMESTAMPING as QuicWallTimes rather
	// than QuicTimes.
	bool FLAGS_quic_socket_walltimestamps = false;

	// If true, default to immediate forward secure once established on the
	// server side, and the IPFS connection option disables this instead of
	// enabling it.
	bool FLAGS_quic_default_immediate_forward_secure = true;

	// If true, disables support for QUIC version 29 and earlier.
	bool FLAGS_quic_disable_pre_30 = false;

	// If true, QUIC respect HTTP2 SETTINGS frame rather than always close the
	// connection.
	bool FLAGS_quic_respect_http2_settings_frame = true;

	// Do not use a QuicAckListener in order to confirm a larger Path MTU.
	bool FLAGS_quic_no_mtu_discovery_ack_listener = false;

	// Deprecate QuicPacketCreator::next_packet_number_length_ because it's no
	// longer necessary.
	bool FLAGS_quic_simple_packet_number_length = false;

	// If true, enables QUIC_VERSION_35.
	bool FLAGS_quic_enable_version_35 = false;