fe267a5590
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. No functional change intended.
247 lines
7.9 KiB
C
247 lines
7.9 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
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* The Regents of the University of California.
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* Copyright (c) 2007-2008,2010
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* Swinburne University of Technology, Melbourne, Australia.
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* Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org>
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* Copyright (c) 2010 The FreeBSD Foundation
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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 of Technology, by Lawrence Stewart, James
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* Healy and David Hayes, made possible in part by a grant from the Cisco
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* University Research Program Fund at Community Foundation Silicon Valley.
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*
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* Portions of this software were developed at the Centre for Advanced
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* Internet Architectures, Swinburne University of Technology, Melbourne,
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* Australia by David Hayes under sponsorship from the FreeBSD Foundation.
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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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/*
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* This software was first released in 2007 by James Healy and Lawrence Stewart
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* whilst working on the NewTCP research project at Swinburne University of
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* Technology's Centre for Advanced Internet Architectures, Melbourne,
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* Australia, which was made possible in part by a grant from the Cisco
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* University Research Program Fund at Community Foundation Silicon Valley.
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* More details are available at:
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* http://caia.swin.edu.au/urp/newtcp/
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <net/vnet.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_var.h>
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#include <netinet/cc/cc.h>
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#include <netinet/cc/cc_module.h>
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static void newreno_ack_received(struct cc_var *ccv, uint16_t type);
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static void newreno_after_idle(struct cc_var *ccv);
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static void newreno_cong_signal(struct cc_var *ccv, uint32_t type);
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static void newreno_post_recovery(struct cc_var *ccv);
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struct cc_algo newreno_cc_algo = {
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.name = "newreno",
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.ack_received = newreno_ack_received,
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.after_idle = newreno_after_idle,
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.cong_signal = newreno_cong_signal,
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.post_recovery = newreno_post_recovery,
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};
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static void
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newreno_ack_received(struct cc_var *ccv, uint16_t type)
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{
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if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) &&
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(ccv->flags & CCF_CWND_LIMITED)) {
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u_int cw = CCV(ccv, snd_cwnd);
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u_int incr = CCV(ccv, t_maxseg);
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/*
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* Regular in-order ACK, open the congestion window.
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* Method depends on which congestion control state we're
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* in (slow start or cong avoid) and if ABC (RFC 3465) is
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* enabled.
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*
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* slow start: cwnd <= ssthresh
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* cong avoid: cwnd > ssthresh
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*
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* slow start and ABC (RFC 3465):
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* Grow cwnd exponentially by the amount of data
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* ACKed capping the max increment per ACK to
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* (abc_l_var * maxseg) bytes.
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*
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* slow start without ABC (RFC 5681):
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* Grow cwnd exponentially by maxseg per ACK.
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*
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* cong avoid and ABC (RFC 3465):
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* Grow cwnd linearly by maxseg per RTT for each
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* cwnd worth of ACKed data.
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*
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* cong avoid without ABC (RFC 5681):
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* Grow cwnd linearly by approximately maxseg per RTT using
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* maxseg^2 / cwnd per ACK as the increment.
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* If cwnd > maxseg^2, fix the cwnd increment at 1 byte to
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* avoid capping cwnd.
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*/
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if (cw > CCV(ccv, snd_ssthresh)) {
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if (V_tcp_do_rfc3465) {
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if (ccv->flags & CCF_ABC_SENTAWND)
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ccv->flags &= ~CCF_ABC_SENTAWND;
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else
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incr = 0;
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} else
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incr = max((incr * incr / cw), 1);
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} else if (V_tcp_do_rfc3465) {
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/*
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* In slow-start with ABC enabled and no RTO in sight?
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* (Must not use abc_l_var > 1 if slow starting after
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* an RTO. On RTO, snd_nxt = snd_una, so the
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* snd_nxt == snd_max check is sufficient to
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* handle this).
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*
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* XXXLAS: Find a way to signal SS after RTO that
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* doesn't rely on tcpcb vars.
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*/
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if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max))
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incr = min(ccv->bytes_this_ack,
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ccv->nsegs * V_tcp_abc_l_var *
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CCV(ccv, t_maxseg));
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else
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incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg));
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}
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/* ABC is on by default, so incr equals 0 frequently. */
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if (incr > 0)
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CCV(ccv, snd_cwnd) = min(cw + incr,
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TCP_MAXWIN << CCV(ccv, snd_scale));
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}
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}
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static void
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newreno_after_idle(struct cc_var *ccv)
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{
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int rw;
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/*
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* If we've been idle for more than one retransmit timeout the old
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* congestion window is no longer current and we have to reduce it to
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* the restart window before we can transmit again.
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*
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* The restart window is the initial window or the last CWND, whichever
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* is smaller.
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*
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* This is done to prevent us from flooding the path with a full CWND at
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* wirespeed, overloading router and switch buffers along the way.
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*
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* See RFC5681 Section 4.1. "Restarting Idle Connections".
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*/
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if (V_tcp_do_rfc3390)
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rw = min(4 * CCV(ccv, t_maxseg),
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max(2 * CCV(ccv, t_maxseg), 4380));
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else
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rw = CCV(ccv, t_maxseg) * 2;
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CCV(ccv, snd_cwnd) = min(rw, CCV(ccv, snd_cwnd));
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}
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/*
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* Perform any necessary tasks before we enter congestion recovery.
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*/
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static void
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newreno_cong_signal(struct cc_var *ccv, uint32_t type)
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{
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u_int win;
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/* Catch algos which mistakenly leak private signal types. */
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KASSERT((type & CC_SIGPRIVMASK) == 0,
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("%s: congestion signal type 0x%08x is private\n", __func__, type));
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win = max(CCV(ccv, snd_cwnd) / 2 / CCV(ccv, t_maxseg), 2) *
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CCV(ccv, t_maxseg);
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switch (type) {
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case CC_NDUPACK:
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if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) {
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if (!IN_CONGRECOVERY(CCV(ccv, t_flags)))
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CCV(ccv, snd_ssthresh) = win;
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ENTER_RECOVERY(CCV(ccv, t_flags));
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}
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break;
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case CC_ECN:
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if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
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CCV(ccv, snd_ssthresh) = win;
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CCV(ccv, snd_cwnd) = win;
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ENTER_CONGRECOVERY(CCV(ccv, t_flags));
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}
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break;
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}
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}
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/*
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* Perform any necessary tasks before we exit congestion recovery.
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*/
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static void
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newreno_post_recovery(struct cc_var *ccv)
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{
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int pipe;
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pipe = 0;
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if (IN_FASTRECOVERY(CCV(ccv, t_flags))) {
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/*
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* Fast recovery will conclude after returning from this
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* function. Window inflation should have left us with
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* approximately snd_ssthresh outstanding data. But in case we
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* would be inclined to send a burst, better to do it via the
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* slow start mechanism.
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*
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* XXXLAS: Find a way to do this without needing curack
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*/
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if (V_tcp_do_rfc6675_pipe)
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pipe = tcp_compute_pipe(ccv->ccvc.tcp);
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else
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pipe = CCV(ccv, snd_max) - ccv->curack;
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if (pipe < CCV(ccv, snd_ssthresh))
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CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
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else
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CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh);
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}
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}
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DECLARE_CC_MODULE(newreno, &newreno_cc_algo);
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