050570efa7
Khelp/Hhook KPIs to hook into the TCP stack and maintain a per-connection, low noise estimate of the instantaneous RTT. ERTT's implementation is robust even in the face of delayed acknowledgements and/or TSO being in use for a connection. A high quality, low noise RTT estimate is a requirement for applications such as delay-based congestion control, for which we will be importing some algorithm implementations shortly. In collaboration with: David Hayes <dahayes at swin edu au> and Grenville Armitage <garmitage at swin edu au> Sponsored by: FreeBSD Foundation Reviewed by: bz and others along the way MFC after: 3 months
90 lines
3.5 KiB
C
90 lines
3.5 KiB
C
/*-
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* Copyright (c) 2009-2010
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* Swinburne University of Technology, Melbourne, Australia
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* Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
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* All rights reserved.
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*
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* This software was developed at the Centre for Advanced Internet
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* Architectures, Swinburne University, by David Hayes, made possible in part by
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* a grant from the Cisco University Research Program Fund at Community
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* Foundation Silicon Valley.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* The ERTT (Enhanced Round Trip Time) Khelp module calculates an estimate of
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* the instantaneous TCP RTT which, for example, is used by delay-based
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* congestion control schemes. When the module is loaded, ERTT data is
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* calculated for each active TCP connection and encapsulated within a
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* "struct ertt".
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*
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* This software was first released in 2010 by David Hayes and Lawrence Stewart
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* whilst working on the NewTCP research project at Swinburne University's
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* Centre for Advanced Internet Architectures, Melbourne, Australia, which was
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* made possible in part by a grant from the Cisco University Research Program
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* Fund at Community Foundation Silicon Valley. Testing and development was
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* further assisted by a grant from the FreeBSD Foundation. More details are
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* available at:
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* http://caia.swin.edu.au/urp/newtcp/
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*/
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#ifndef _NETINET_KHELP_H_ERTT_
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#define _NETINET_KHELP_H_ERTT_
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struct txseginfo;
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/* Structure used as the ertt data block. */
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struct ertt {
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/* Information about transmitted segments to aid in RTT calculation. */
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TAILQ_HEAD(txseginfo_head, txseginfo) txsegi_q;
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/* Bytes TX so far in marked RTT. */
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long bytes_tx_in_rtt;
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/* Final version of above. */
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long bytes_tx_in_marked_rtt;
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/* cwnd for marked RTT. */
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unsigned long marked_snd_cwnd;
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/* Per-packet measured RTT. */
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int rtt;
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/* Maximum RTT measured. */
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int maxrtt;
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/* Minimum RTT measured. */
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int minrtt;
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/* Guess if the receiver is using delayed ack. */
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int dlyack_rx;
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/* Keep track of inconsistencies in packet timestamps. */
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int timestamp_errors;
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/* RTT for a marked packet. */
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int markedpkt_rtt;
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/* Flags to signal conditions between hook function calls. */
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uint32_t flags;
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};
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/* Flags for struct ertt. */
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#define ERTT_NEW_MEASUREMENT 0x01
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#define ERTT_MEASUREMENT_IN_PROGRESS 0x02
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#define ERTT_TSO_DISABLED 0x04
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#endif /* _NETINET_KHELP_H_ERTT_ */
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