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- /*-
- * 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 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>
- /*
- * 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;
- VNET_DEFINE_STATIC(uint32_t, vegas_alpha) = 1;
- VNET_DEFINE_STATIC(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)
- {
- 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 (new == 0 || new > 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 (new == 0 || new < 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 | CTLFLAG_MPSAFE, NULL,
- "Vegas related settings");
- SYSCTL_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, alpha,
- CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
- &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 | CTLFLAG_NEEDGIANT,
- &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_VERSION(vegas, 1);
- MODULE_DEPEND(vegas, ertt, 1, 1, 1);
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