2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2009-2010
5 * Swinburne University of Technology, Melbourne, Australia
6 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
9 * This software was developed at the Centre for Advanced Internet
10 * Architectures, Swinburne University of Technology, by David Hayes, made
11 * possible in part by a grant from the Cisco University Research Program Fund
12 * at Community Foundation Silicon Valley.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * The ERTT (Enhanced Round Trip Time) Khelp module calculates an estimate of
40 * the instantaneous TCP RTT which, for example, is used by delay-based
41 * congestion control schemes. When the module is loaded, ERTT data is
42 * calculated for each active TCP connection and encapsulated within a
45 * This software was first released in 2010 by David Hayes and Lawrence Stewart
46 * whilst working on the NewTCP research project at Swinburne University of
47 * Technology's Centre for Advanced Internet Architectures, Melbourne,
48 * Australia, which was made possible in part by a grant from the Cisco
49 * University Research Program Fund at Community Foundation Silicon Valley.
50 * Testing and development was further assisted by a grant from the FreeBSD
51 * Foundation. More details are available at:
52 * http://caia.swin.edu.au/urp/newtcp/
55 #ifndef _NETINET_KHELP_H_ERTT_
56 #define _NETINET_KHELP_H_ERTT_
60 /* Structure used as the ertt data block. */
62 /* Information about transmitted segments to aid in RTT calculation. */
63 TAILQ_HEAD(txseginfo_head, txseginfo) txsegi_q;
64 /* Bytes TX so far in marked RTT. */
66 /* Final version of above. */
67 long bytes_tx_in_marked_rtt;
68 /* cwnd for marked RTT. */
69 unsigned long marked_snd_cwnd;
70 /* Per-packet measured RTT. */
72 /* Maximum RTT measured. */
74 /* Minimum RTT measured. */
76 /* Guess if the receiver is using delayed ack. */
78 /* Keep track of inconsistencies in packet timestamps. */
80 /* RTT for a marked packet. */
82 /* Flags to signal conditions between hook function calls. */
86 /* Flags for struct ertt. */
87 #define ERTT_NEW_MEASUREMENT 0x01
88 #define ERTT_MEASUREMENT_IN_PROGRESS 0x02
89 #define ERTT_TSO_DISABLED 0x04
91 #endif /* _NETINET_KHELP_H_ERTT_ */