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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 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>
- /* 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;
- VNET_DEFINE_STATIC(uint32_t, hd_qthresh) = 20;
- VNET_DEFINE_STATIC(uint32_t, hd_qmin) = 5;
- VNET_DEFINE_STATIC(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 (new == 0 || new > 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 (new > 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 (new == 0 || new < 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 | CTLFLAG_MPSAFE, 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 | CTLFLAG_NEEDGIANT,
- &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 | CTLFLAG_NEEDGIANT,
- &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 | CTLFLAG_NEEDGIANT,
- &VNET_NAME(hd_qmin), 5, &hd_qmin_handler, "IU",
- "minimum queueing delay threshold (qmin) in ticks");
- DECLARE_CC_MODULE(hd, &hd_cc_algo);
- MODULE_VERSION(hd, 1);
- MODULE_DEPEND(hd, ertt, 1, 1, 1);
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