1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2009-2010 5 * Swinburne University of Technology, Melbourne, Australia 6 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org> 7 * All rights reserved. 8 * 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. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 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. 22 * 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 33 * SUCH DAMAGE. 34 */ 35 36 /* 37 * The ERTT (Enhanced Round Trip Time) Khelp module calculates an estimate of 38 * the instantaneous TCP RTT which, for example, is used by delay-based 39 * congestion control schemes. When the module is loaded, ERTT data is 40 * calculated for each active TCP connection and encapsulated within a 41 * "struct ertt". 42 * 43 * This software was first released in 2010 by David Hayes and Lawrence Stewart 44 * whilst working on the NewTCP research project at Swinburne University of 45 * Technology's Centre for Advanced Internet Architectures, Melbourne, 46 * Australia, which was made possible in part by a grant from the Cisco 47 * University Research Program Fund at Community Foundation Silicon Valley. 48 * Testing and development was further assisted by a grant from the FreeBSD 49 * Foundation. More details are available at: 50 * http://caia.swin.edu.au/urp/newtcp/ 51 */ 52 53 #ifndef _NETINET_KHELP_H_ERTT_ 54 #define _NETINET_KHELP_H_ERTT_ 55 56 struct txseginfo; 57 58 /* Structure used as the ertt data block. */ 59 struct ertt { 60 /* Information about transmitted segments to aid in RTT calculation. */ 61 TAILQ_HEAD(txseginfo_head, txseginfo) txsegi_q; 62 /* Bytes TX so far in marked RTT. */ 63 long bytes_tx_in_rtt; 64 /* Final version of above. */ 65 long bytes_tx_in_marked_rtt; 66 /* cwnd for marked RTT. */ 67 unsigned long marked_snd_cwnd; 68 /* Per-packet measured RTT. */ 69 int rtt; 70 /* Maximum RTT measured. */ 71 int maxrtt; 72 /* Minimum RTT measured. */ 73 int minrtt; 74 /* Guess if the receiver is using delayed ack. */ 75 int dlyack_rx; 76 /* Keep track of inconsistencies in packet timestamps. */ 77 int timestamp_errors; 78 /* RTT for a marked packet. */ 79 int markedpkt_rtt; 80 /* Flags to signal conditions between hook function calls. */ 81 uint32_t flags; 82 }; 83 84 /* Flags for struct ertt. */ 85 #define ERTT_NEW_MEASUREMENT 0x01 86 #define ERTT_MEASUREMENT_IN_PROGRESS 0x02 87 #define ERTT_TSO_DISABLED 0x04 88 89 #endif /* _NETINET_KHELP_H_ERTT_ */ 90