308 lines
8.9 KiB
C
308 lines
8.9 KiB
C
/*-
|
|
* 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 Vegas congestion control algorithm for FreeBSD,
|
|
* based on L. S. Brakmo and L. L. Peterson, "TCP Vegas: end to end congestion
|
|
* avoidance on a global internet", IEEE J. Sel. Areas Commun., vol. 13, no. 8,
|
|
* pp. 1465-1480, Oct. 1995. The original Vegas duplicate ack policy has not
|
|
* been implemented, since clock ticks are not as coarse as they were (i.e.
|
|
* 500ms) when Vegas was designed. Also, packets are timed once per RTT as in
|
|
* the original paper.
|
|
*
|
|
* 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/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_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)))
|
|
|
|
/*
|
|
* Private signal type for rate based congestion signal.
|
|
* See <netinet/cc.h> for appropriate bit-range to use for private signals.
|
|
*/
|
|
#define CC_VEGAS_RATE 0x01000000
|
|
|
|
static void vegas_ack_received(struct cc_var *ccv, uint16_t ack_type);
|
|
static void vegas_cb_destroy(struct cc_var *ccv);
|
|
static int vegas_cb_init(struct cc_var *ccv);
|
|
static void vegas_cong_signal(struct cc_var *ccv, uint32_t signal_type);
|
|
static void vegas_conn_init(struct cc_var *ccv);
|
|
static int vegas_mod_init(void);
|
|
|
|
struct vegas {
|
|
int slow_start_toggle;
|
|
};
|
|
|
|
static int32_t ertt_id;
|
|
|
|
static VNET_DEFINE(uint32_t, vegas_alpha) = 1;
|
|
static VNET_DEFINE(uint32_t, vegas_beta) = 3;
|
|
#define V_vegas_alpha VNET(vegas_alpha)
|
|
#define V_vegas_beta VNET(vegas_beta)
|
|
|
|
static MALLOC_DEFINE(M_VEGAS, "vegas data",
|
|
"Per connection data required for the Vegas congestion control algorithm");
|
|
|
|
struct cc_algo vegas_cc_algo = {
|
|
.name = "vegas",
|
|
.ack_received = vegas_ack_received,
|
|
.cb_destroy = vegas_cb_destroy,
|
|
.cb_init = vegas_cb_init,
|
|
.cong_signal = vegas_cong_signal,
|
|
.conn_init = vegas_conn_init,
|
|
.mod_init = vegas_mod_init
|
|
};
|
|
|
|
/*
|
|
* The vegas window adjustment is done once every RTT, as indicated by the
|
|
* ERTT_NEW_MEASUREMENT flag. This flag is reset once the new measurment data
|
|
* has been used.
|
|
*/
|
|
static void
|
|
vegas_ack_received(struct cc_var *ccv, uint16_t ack_type)
|
|
{
|
|
struct ertt *e_t;
|
|
struct vegas *vegas_data;
|
|
long actual_tx_rate, expected_tx_rate, ndiff;
|
|
|
|
e_t = khelp_get_osd(CCV(ccv, osd), ertt_id);
|
|
vegas_data = ccv->cc_data;
|
|
|
|
if (e_t->flags & ERTT_NEW_MEASUREMENT) { /* Once per RTT. */
|
|
if (e_t->minrtt && e_t->markedpkt_rtt) {
|
|
expected_tx_rate = e_t->marked_snd_cwnd / e_t->minrtt;
|
|
actual_tx_rate = e_t->bytes_tx_in_marked_rtt /
|
|
e_t->markedpkt_rtt;
|
|
ndiff = (expected_tx_rate - actual_tx_rate) *
|
|
e_t->minrtt / CCV(ccv, t_maxseg);
|
|
|
|
if (ndiff < V_vegas_alpha) {
|
|
if (CCV(ccv, snd_cwnd) <=
|
|
CCV(ccv, snd_ssthresh)) {
|
|
vegas_data->slow_start_toggle =
|
|
vegas_data->slow_start_toggle ?
|
|
0 : 1;
|
|
} else {
|
|
vegas_data->slow_start_toggle = 0;
|
|
CCV(ccv, snd_cwnd) =
|
|
min(CCV(ccv, snd_cwnd) +
|
|
CCV(ccv, t_maxseg),
|
|
TCP_MAXWIN << CCV(ccv, snd_scale));
|
|
}
|
|
} else if (ndiff > V_vegas_beta) {
|
|
/* Rate-based congestion. */
|
|
vegas_cong_signal(ccv, CC_VEGAS_RATE);
|
|
vegas_data->slow_start_toggle = 0;
|
|
}
|
|
}
|
|
e_t->flags &= ~ERTT_NEW_MEASUREMENT;
|
|
}
|
|
|
|
if (vegas_data->slow_start_toggle)
|
|
newreno_cc_algo.ack_received(ccv, ack_type);
|
|
}
|
|
|
|
static void
|
|
vegas_cb_destroy(struct cc_var *ccv)
|
|
{
|
|
|
|
if (ccv->cc_data != NULL)
|
|
free(ccv->cc_data, M_VEGAS);
|
|
}
|
|
|
|
static int
|
|
vegas_cb_init(struct cc_var *ccv)
|
|
{
|
|
struct vegas *vegas_data;
|
|
|
|
vegas_data = malloc(sizeof(struct vegas), M_VEGAS, M_NOWAIT);
|
|
|
|
if (vegas_data == NULL)
|
|
return (ENOMEM);
|
|
|
|
vegas_data->slow_start_toggle = 1;
|
|
ccv->cc_data = vegas_data;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* If congestion has been triggered triggered by the Vegas measured rates, it is
|
|
* handled here, otherwise it falls back to newreno's congestion handling.
|
|
*/
|
|
static void
|
|
vegas_cong_signal(struct cc_var *ccv, uint32_t signal_type)
|
|
{
|
|
struct vegas *vegas_data;
|
|
int presignalrecov;
|
|
|
|
vegas_data = ccv->cc_data;
|
|
|
|
if (IN_RECOVERY(CCV(ccv, t_flags)))
|
|
presignalrecov = 1;
|
|
else
|
|
presignalrecov = 0;
|
|
|
|
switch(signal_type) {
|
|
case CC_VEGAS_RATE:
|
|
if (!IN_RECOVERY(CCV(ccv, t_flags))) {
|
|
CCV(ccv, snd_cwnd) = max(2 * CCV(ccv, t_maxseg),
|
|
CCV(ccv, snd_cwnd) - CCV(ccv, t_maxseg));
|
|
if (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh))
|
|
/* Exit slow start. */
|
|
CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd);
|
|
}
|
|
break;
|
|
|
|
default:
|
|
newreno_cc_algo.cong_signal(ccv, signal_type);
|
|
}
|
|
|
|
if (IN_RECOVERY(CCV(ccv, t_flags)) && !presignalrecov)
|
|
vegas_data->slow_start_toggle =
|
|
(CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh)) ? 1 : 0;
|
|
}
|
|
|
|
static void
|
|
vegas_conn_init(struct cc_var *ccv)
|
|
{
|
|
struct vegas *vegas_data;
|
|
|
|
vegas_data = ccv->cc_data;
|
|
vegas_data->slow_start_toggle = 1;
|
|
}
|
|
|
|
static int
|
|
vegas_mod_init(void)
|
|
{
|
|
|
|
ertt_id = khelp_get_id("ertt");
|
|
if (ertt_id <= 0) {
|
|
printf("%s: h_ertt module not found\n", __func__);
|
|
return (ENOENT);
|
|
}
|
|
|
|
vegas_cc_algo.after_idle = newreno_cc_algo.after_idle;
|
|
vegas_cc_algo.post_recovery = newreno_cc_algo.post_recovery;
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
vegas_alpha_handler(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
uint32_t new;
|
|
|
|
new = V_vegas_alpha;
|
|
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_vegas_beta)
|
|
error = EINVAL;
|
|
else
|
|
V_vegas_alpha = new;
|
|
}
|
|
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
vegas_beta_handler(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
uint32_t new;
|
|
|
|
new = V_vegas_beta;
|
|
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_vegas_alpha)
|
|
error = EINVAL;
|
|
else
|
|
V_vegas_beta = new;
|
|
}
|
|
|
|
return (error);
|
|
}
|
|
|
|
SYSCTL_DECL(_net_inet_tcp_cc_vegas);
|
|
SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, vegas, CTLFLAG_RW, NULL,
|
|
"Vegas related settings");
|
|
|
|
SYSCTL_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, alpha,
|
|
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW,
|
|
&VNET_NAME(vegas_alpha), 1, &vegas_alpha_handler, "IU",
|
|
"vegas alpha, specified as number of \"buffers\" (0 < alpha < beta)");
|
|
|
|
SYSCTL_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, beta,
|
|
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW,
|
|
&VNET_NAME(vegas_beta), 3, &vegas_beta_handler, "IU",
|
|
"vegas beta, specified as number of \"buffers\" (0 < alpha < beta)");
|
|
|
|
DECLARE_CC_MODULE(vegas, &vegas_cc_algo);
|
|
MODULE_DEPEND(vegas, ertt, 1, 1, 1);
|