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