freebsd-dev/sys/netinet/cc/cc_hd.c
Pedro F. Giffuni fe267a5590 sys: general adoption of SPDX licensing ID tags.
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.
2017-11-27 15:23:17 +00:00

257 lines
7.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009-2010
* Swinburne University of Technology, Melbourne, Australia
* Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
* Copyright (c) 2010-2011 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed at the Centre for Advanced Internet
* Architectures, Swinburne University of Technology, by David Hayes and
* Lawrence Stewart, made possible in part by a grant from the Cisco University
* Research Program Fund at Community Foundation Silicon Valley.
*
* Portions of this software were developed at the Centre for Advanced Internet
* Architectures, Swinburne University of Technology, Melbourne, Australia by
* David Hayes under sponsorship from the FreeBSD Foundation.
*
* 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.
*/
/*
* An implementation of the Hamilton Institute's delay-based congestion control
* algorithm for FreeBSD, based on "A strategy for fair coexistence of loss and
* delay-based congestion control algorithms," by L. Budzisz, R. Stanojevic, R.
* Shorten, and F. Baker, IEEE Commun. Lett., vol. 13, no. 7, pp. 555--557, Jul.
* 2009.
*
* Originally released as part of 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. More details are available at:
* http://caia.swin.edu.au/urp/newtcp/
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/khelp.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <net/vnet.h>
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/cc/cc.h>
#include <netinet/cc/cc_module.h>
#include <netinet/khelp/h_ertt.h>
#define CAST_PTR_INT(X) (*((int*)(X)))
/* Largest possible number returned by random(). */
#define RANDOM_MAX INT_MAX
static void hd_ack_received(struct cc_var *ccv, uint16_t ack_type);
static int hd_mod_init(void);
static int ertt_id;
static VNET_DEFINE(uint32_t, hd_qthresh) = 20;
static VNET_DEFINE(uint32_t, hd_qmin) = 5;
static VNET_DEFINE(uint32_t, hd_pmax) = 5;
#define V_hd_qthresh VNET(hd_qthresh)
#define V_hd_qmin VNET(hd_qmin)
#define V_hd_pmax VNET(hd_pmax)
struct cc_algo hd_cc_algo = {
.name = "hd",
.ack_received = hd_ack_received,
.mod_init = hd_mod_init
};
/*
* Hamilton backoff function. Returns 1 if we should backoff or 0 otherwise.
*/
static __inline int
should_backoff(int qdly, int maxqdly)
{
unsigned long p;
if (qdly < V_hd_qthresh) {
p = (((RANDOM_MAX / 100) * V_hd_pmax) /
(V_hd_qthresh - V_hd_qmin)) * (qdly - V_hd_qmin);
} else {
if (qdly > V_hd_qthresh)
p = (((RANDOM_MAX / 100) * V_hd_pmax) /
(maxqdly - V_hd_qthresh)) * (maxqdly - qdly);
else
p = (RANDOM_MAX / 100) * V_hd_pmax;
}
return (random() < p);
}
/*
* If the ack type is CC_ACK, and the inferred queueing delay is greater than
* the Qmin threshold, cwnd is reduced probabilistically. When backing off due
* to delay, HD behaves like NewReno when an ECN signal is received. HD behaves
* as NewReno in all other circumstances.
*/
static void
hd_ack_received(struct cc_var *ccv, uint16_t ack_type)
{
struct ertt *e_t;
int qdly;
if (ack_type == CC_ACK) {
e_t = khelp_get_osd(CCV(ccv, osd), ertt_id);
if (e_t->rtt && e_t->minrtt && V_hd_qthresh > 0) {
qdly = e_t->rtt - e_t->minrtt;
if (qdly > V_hd_qmin &&
!IN_RECOVERY(CCV(ccv, t_flags))) {
/* Probabilistic backoff of cwnd. */
if (should_backoff(qdly,
e_t->maxrtt - e_t->minrtt)) {
/*
* Update cwnd and ssthresh update to
* half cwnd and behave like an ECN (ie
* not a packet loss).
*/
newreno_cc_algo.cong_signal(ccv,
CC_ECN);
return;
}
}
}
}
newreno_cc_algo.ack_received(ccv, ack_type); /* As for NewReno. */
}
static int
hd_mod_init(void)
{
ertt_id = khelp_get_id("ertt");
if (ertt_id <= 0) {
printf("%s: h_ertt module not found\n", __func__);
return (ENOENT);
}
hd_cc_algo.after_idle = newreno_cc_algo.after_idle;
hd_cc_algo.cong_signal = newreno_cc_algo.cong_signal;
hd_cc_algo.post_recovery = newreno_cc_algo.post_recovery;
return (0);
}
static int
hd_pmax_handler(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = V_hd_pmax;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr != NULL) {
if (CAST_PTR_INT(req->newptr) == 0 ||
CAST_PTR_INT(req->newptr) > 100)
error = EINVAL;
else
V_hd_pmax = new;
}
return (error);
}
static int
hd_qmin_handler(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = V_hd_qmin;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr != NULL) {
if (CAST_PTR_INT(req->newptr) > V_hd_qthresh)
error = EINVAL;
else
V_hd_qmin = new;
}
return (error);
}
static int
hd_qthresh_handler(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = V_hd_qthresh;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr != NULL) {
if (CAST_PTR_INT(req->newptr) < 1 ||
CAST_PTR_INT(req->newptr) < V_hd_qmin)
error = EINVAL;
else
V_hd_qthresh = new;
}
return (error);
}
SYSCTL_DECL(_net_inet_tcp_cc_hd);
SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, hd, CTLFLAG_RW, NULL,
"Hamilton delay-based congestion control related settings");
SYSCTL_PROC(_net_inet_tcp_cc_hd, OID_AUTO, queue_threshold,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, &VNET_NAME(hd_qthresh), 20,
&hd_qthresh_handler, "IU", "queueing congestion threshold (qth) in ticks");
SYSCTL_PROC(_net_inet_tcp_cc_hd, OID_AUTO, pmax,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, &VNET_NAME(hd_pmax), 5,
&hd_pmax_handler, "IU",
"per packet maximum backoff probability as a percentage");
SYSCTL_PROC(_net_inet_tcp_cc_hd, OID_AUTO, queue_min,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, &VNET_NAME(hd_qmin), 5,
&hd_qmin_handler, "IU", "minimum queueing delay threshold (qmin) in ticks");
DECLARE_CC_MODULE(hd, &hd_cc_algo);
MODULE_DEPEND(hd, ertt, 1, 1, 1);