fa3746be42
* Completely initialise the CC module specific data * Use beta_ecn in case of an ECN event whenever ABE is enabled or it is requested by the stack. Reviewed by: rscheff, rrs MFC after: 3 days Sponsored by: Netflix, Inc.
431 lines
13 KiB
C
431 lines
13 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) 2007-2008,2010,2014
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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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* Dec 2014 garmitage@swin.edu.au
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* Borrowed code fragments from cc_cdg.c to add modifiable beta
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* via sysctls.
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*
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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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#include <netinet/cc/cc_newreno.h>
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static MALLOC_DEFINE(M_NEWRENO, "newreno data",
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"newreno beta values");
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static void newreno_cb_destroy(struct cc_var *ccv);
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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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static int newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf);
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VNET_DEFINE(uint32_t, newreno_beta) = 50;
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VNET_DEFINE(uint32_t, newreno_beta_ecn) = 80;
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#define V_newreno_beta VNET(newreno_beta)
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#define V_newreno_beta_ecn VNET(newreno_beta_ecn)
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struct cc_algo newreno_cc_algo = {
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.name = "newreno",
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.cb_destroy = newreno_cb_destroy,
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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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.ctl_output = newreno_ctl_output,
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};
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static inline struct newreno *
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newreno_malloc(struct cc_var *ccv)
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{
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struct newreno *nreno;
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nreno = malloc(sizeof(struct newreno), M_NEWRENO, M_NOWAIT);
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if (nreno != NULL) {
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/* NB: nreno is not zeroed, so initialise all fields. */
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nreno->beta = V_newreno_beta;
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nreno->beta_ecn = V_newreno_beta_ecn;
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nreno->newreno_flags = 0;
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ccv->cc_data = nreno;
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}
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return (nreno);
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}
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static void
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newreno_cb_destroy(struct cc_var *ccv)
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{
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free(ccv->cc_data, M_NEWRENO);
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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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uint16_t abc_val;
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if (ccv->flags & CCF_USE_LOCAL_ABC)
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abc_val = ccv->labc;
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else
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abc_val = V_tcp_abc_l_var;
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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 * abc_val *
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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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uint32_t 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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* In addition, per RFC2861 Section 2, the ssthresh is set to the
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* maximum of the former ssthresh or 3/4 of the old cwnd, to
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* not exit slow-start prematurely.
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*/
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rw = tcp_compute_initwnd(tcp_maxseg(ccv->ccvc.tcp));
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CCV(ccv, snd_ssthresh) = max(CCV(ccv, snd_ssthresh),
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CCV(ccv, snd_cwnd)-(CCV(ccv, snd_cwnd)>>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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struct newreno *nreno;
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uint32_t beta, beta_ecn, cwin, factor;
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u_int mss;
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cwin = CCV(ccv, snd_cwnd);
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mss = tcp_fixed_maxseg(ccv->ccvc.tcp);
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/*
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* Other TCP congestion controls use newreno_cong_signal(), but
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* with their own private cc_data. Make sure the cc_data is used
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* correctly.
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*/
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nreno = (CC_ALGO(ccv->ccvc.tcp) == &newreno_cc_algo) ? ccv->cc_data : NULL;
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beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;
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beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn;
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/*
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* Note that we only change the backoff for ECN if the
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* global sysctl V_cc_do_abe is set <or> the stack itself
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* has set a flag in our newreno_flags (due to pacing) telling
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* us to use the lower valued back-off.
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*/
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if ((type == CC_ECN) &&
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(V_cc_do_abe ||
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((nreno != NULL) && (nreno->newreno_flags & CC_NEWRENO_BETA_ECN))))
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factor = beta_ecn;
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else
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factor = beta;
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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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cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss),
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2) * mss;
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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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V_cc_do_abe && V_cc_abe_frlossreduce)) {
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CCV(ccv, snd_ssthresh) =
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((uint64_t)CCV(ccv, snd_ssthresh) *
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(uint64_t)beta) / (uint64_t)beta_ecn;
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}
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if (!IN_CONGRECOVERY(CCV(ccv, t_flags)))
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CCV(ccv, snd_ssthresh) = cwin;
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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) = cwin;
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CCV(ccv, snd_cwnd) = cwin;
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ENTER_CONGRECOVERY(CCV(ccv, t_flags));
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}
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break;
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case CC_RTO:
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CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd),
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CCV(ccv, snd_cwnd)) / 2 / mss,
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2) * mss;
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CCV(ccv, snd_cwnd) = mss;
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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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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_newsack)
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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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/*
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* Ensure that cwnd does not collapse to 1 MSS under
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* adverse conditons. Implements RFC6582
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*/
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CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
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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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static int
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newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf)
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{
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struct newreno *nreno;
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struct cc_newreno_opts *opt;
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if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts))
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return (EMSGSIZE);
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if (CC_ALGO(ccv->ccvc.tcp) != &newreno_cc_algo)
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return (ENOPROTOOPT);
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nreno = ccv->cc_data;
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opt = buf;
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switch (sopt->sopt_dir) {
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case SOPT_SET:
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/* We cannot set without cc_data memory. */
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if (nreno == NULL) {
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nreno = newreno_malloc(ccv);
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if (nreno == NULL)
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return (ENOMEM);
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}
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switch (opt->name) {
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case CC_NEWRENO_BETA:
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nreno->beta = opt->val;
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break;
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case CC_NEWRENO_BETA_ECN:
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if ((!V_cc_do_abe) && ((nreno->newreno_flags & CC_NEWRENO_BETA_ECN) == 0))
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return (EACCES);
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nreno->beta_ecn = opt->val;
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break;
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default:
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return (ENOPROTOOPT);
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}
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break;
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case SOPT_GET:
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switch (opt->name) {
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case CC_NEWRENO_BETA:
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opt->val = (nreno == NULL) ?
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V_newreno_beta : nreno->beta;
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break;
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case CC_NEWRENO_BETA_ECN:
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opt->val = (nreno == NULL) ?
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V_newreno_beta_ecn : nreno->beta_ecn;
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break;
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default:
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return (ENOPROTOOPT);
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}
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break;
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default:
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return (EINVAL);
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}
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return (0);
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}
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static int
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newreno_beta_handler(SYSCTL_HANDLER_ARGS)
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{
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int error;
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uint32_t new;
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new = *(uint32_t *)arg1;
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error = sysctl_handle_int(oidp, &new, 0, req);
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if (error == 0 && req->newptr != NULL ) {
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if (arg1 == &VNET_NAME(newreno_beta_ecn) && !V_cc_do_abe)
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error = EACCES;
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else if (new == 0 || new > 100)
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error = EINVAL;
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else
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*(uint32_t *)arg1 = new;
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}
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return (error);
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}
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SYSCTL_DECL(_net_inet_tcp_cc_newreno);
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SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, newreno,
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CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
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"New Reno related settings");
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SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta,
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CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
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&VNET_NAME(newreno_beta), 3, &newreno_beta_handler, "IU",
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"New Reno beta, specified as number between 1 and 100");
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SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta_ecn,
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CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
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&VNET_NAME(newreno_beta_ecn), 3, &newreno_beta_handler, "IU",
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"New Reno beta ecn, specified as number between 1 and 100");
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DECLARE_CC_MODULE(newreno, &newreno_cc_algo);
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MODULE_VERSION(newreno, 1);
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