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"

 // When true, the use time based loss detection instead of nack.
 bool FLAGS_quic_use_time_loss_detection = false;

 // 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 connections will support FEC protection of data while sending
 // packets, to reduce latency of data delivery to the application. The client
 // must also request FEC protection for the server to use FEC.
 bool FLAGS_enable_quic_fec = true;

 // When true, defaults to BBR congestion control instead of Cubic.
 bool FLAGS_quic_use_bbr_congestion_control = false;

 // 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;

 // If ture, allow Ack Decimation to be used for QUIC when requested by the
 // client connection option ACKD.
 bool FLAGS_quic_ack_decimation = true;

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

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

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

 // Limits QUIC's max CWND to 200 packets.
 bool FLAGS_quic_limit_max_cwnd = true;

 // 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;

 // Disable QUIC's userspace pacing.
 bool FLAGS_quic_disable_pacing = false;

 // If true, Use QUIC's GeneralLossAlgorithm implementation instead of
 // TcpLossAlgorithm or TimeLossAlgorithm.
 bool FLAGS_quic_general_loss_algorithm = true;

 // If true, only migrate QUIC connections when client address changes are
 // considered to be caused by NATs.
 bool FLAGS_quic_disable_non_nat_address_migration = true;

 // If true, QUIC connections will timeout when packets are not being recieved,
 // even if they are being sent.
 bool FLAGS_quic_use_new_idle_timeout = true;

 // If true, replace QuicFrameList with StreamSequencerBuffer as underlying data
 // structure for QuicStreamSequencer bufferring.
 bool FLAGS_quic_use_stream_sequencer_buffer = true;

 // If true, don't send QUIC packets if the send alarm is set.
 bool FLAGS_quic_respect_send_alarm2 = true;

 // If ture, sets callback pointer to nullptr after calling Cancel() in
 // QuicCryptoServerStream::CancelOutstandingCallbacks.
 bool FLAGS_quic_set_client_hello_cb_nullptr = true;

 // If treu, Only track a single retransmission in QUIC's TransmissionInfo
 // struct.
 bool FLAGS_quic_track_single_retransmission = true;

 // If true, allow each quic stream to write 16k blocks rather than doing a round
 // robin of one packet per session when ack clocked or paced.
 bool FLAGS_quic_batch_writes = true;

 // If true, QUIC sessions will write block streams that attempt to write
 // unencrypted data.
 bool FLAGS_quic_block_unencrypted_writes = true;

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

 // If true, clear the FEC group instead of sending it with ENCRYPTION_NONE.
 // Close the connection if we ever try to serialized unencrypted FEC.
 bool FLAGS_quic_no_unencrypted_fec = true;

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

 // If true, QUIC supports sending trailers from Server to Client.
 bool FLAGS_quic_supports_trailers = true;

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

 // Fixes a bug in QUIC_VERSION_26 by always using the primary config when
 // getting the proof of possession.
 bool FLAGS_quic_use_primary_config_for_proof = true;

 // Enable counters for incoming/outgoing streams which are used as condition
 // check while creating a new stream.
 bool FLAGS_quic_distinguish_incoming_outgoing_streams = true;

 // If true, QUIC servers will attempt to validate a client's source
 // address token using the primary config, even if no server config id
 // is present in the client hello.
 bool FLAGS_quic_validate_stk_without_scid = true;

 // If true, use the new write blocked list for QUIC.
 bool FLAGS_quic_new_blocked_list = true;

 // If true, QUIC will support RFC 7539 variants of ChaCha20 Poly1305.
 bool FLAGS_quic_use_rfc7539 = true;

 // If true, drop not awaited QUIC packets before decrypting them.
 bool FLAGS_quic_drop_non_awaited_packets = false;

 // If true, use the fast implementation of IncrementalHash/FNV1a_128_Hash.
 bool FLAGS_quic_utils_use_fast_incremental_hash = true;

 // If true, require QUIC connections to use a valid server nonce or a non-local
 // strike register.
 bool FLAGS_require_strike_register_or_server_nonce = 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.

	#include "net/quic/quic_flags.h"

	// When true, the use time based loss detection instead of nack.
	bool FLAGS_quic_use_time_loss_detection = false;

	// 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 connections will support FEC protection of data while sending
	// packets, to reduce latency of data delivery to the application. The client
	// must also request FEC protection for the server to use FEC.
	bool FLAGS_enable_quic_fec = true;

	// When true, defaults to BBR congestion control instead of Cubic.
	bool FLAGS_quic_use_bbr_congestion_control = false;

	// 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;

	// If ture, allow Ack Decimation to be used for QUIC when requested by the
	// client connection option ACKD.
	bool FLAGS_quic_ack_decimation = true;

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

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

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

	// Limits QUIC's max CWND to 200 packets.
	bool FLAGS_quic_limit_max_cwnd = true;

	// 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;

	// Disable QUIC's userspace pacing.
	bool FLAGS_quic_disable_pacing = false;

	// If true, Use QUIC's GeneralLossAlgorithm implementation instead of
	// TcpLossAlgorithm or TimeLossAlgorithm.
	bool FLAGS_quic_general_loss_algorithm = true;

	// If true, only migrate QUIC connections when client address changes are
	// considered to be caused by NATs.
	bool FLAGS_quic_disable_non_nat_address_migration = true;

	// If true, QUIC connections will timeout when packets are not being recieved,
	// even if they are being sent.
	bool FLAGS_quic_use_new_idle_timeout = true;

	// If true, replace QuicFrameList with StreamSequencerBuffer as underlying data
	// structure for QuicStreamSequencer bufferring.
	bool FLAGS_quic_use_stream_sequencer_buffer = true;

	// If true, don't send QUIC packets if the send alarm is set.
	bool FLAGS_quic_respect_send_alarm2 = true;

	// If ture, sets callback pointer to nullptr after calling Cancel() in
	// QuicCryptoServerStream::CancelOutstandingCallbacks.
	bool FLAGS_quic_set_client_hello_cb_nullptr = true;

	// If treu, Only track a single retransmission in QUIC's TransmissionInfo
	// struct.
	bool FLAGS_quic_track_single_retransmission = true;

	// If true, allow each quic stream to write 16k blocks rather than doing a round
	// robin of one packet per session when ack clocked or paced.
	bool FLAGS_quic_batch_writes = true;

	// If true, QUIC sessions will write block streams that attempt to write
	// unencrypted data.
	bool FLAGS_quic_block_unencrypted_writes = true;

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

	// If true, clear the FEC group instead of sending it with ENCRYPTION_NONE.
	// Close the connection if we ever try to serialized unencrypted FEC.
	bool FLAGS_quic_no_unencrypted_fec = true;

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

	// If true, QUIC supports sending trailers from Server to Client.
	bool FLAGS_quic_supports_trailers = true;

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

	// Fixes a bug in QUIC_VERSION_26 by always using the primary config when
	// getting the proof of possession.
	bool FLAGS_quic_use_primary_config_for_proof = true;

	// Enable counters for incoming/outgoing streams which are used as condition
	// check while creating a new stream.
	bool FLAGS_quic_distinguish_incoming_outgoing_streams = true;

	// If true, QUIC servers will attempt to validate a client's source
	// address token using the primary config, even if no server config id
	// is present in the client hello.
	bool FLAGS_quic_validate_stk_without_scid = true;

	// If true, use the new write blocked list for QUIC.
	bool FLAGS_quic_new_blocked_list = true;

	// If true, QUIC will support RFC 7539 variants of ChaCha20 Poly1305.
	bool FLAGS_quic_use_rfc7539 = true;

	// If true, drop not awaited QUIC packets before decrypting them.
	bool FLAGS_quic_drop_non_awaited_packets = false;

	// If true, use the fast implementation of IncrementalHash/FNV1a_128_Hash.
	bool FLAGS_quic_utils_use_fast_incremental_hash = true;

	// If true, require QUIC connections to use a valid server nonce or a non-local
	// strike register.
	bool FLAGS_require_strike_register_or_server_nonce = true;