/*- * Copyright (c) 2009-2010 * Swinburne University of Technology, Melbourne, Australia * Copyright (c) 2010 Lawrence Stewart * 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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_VNET_PROC(_net_inet_tcp_cc_hd, OID_AUTO, queue_threshold, CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(hd_qthresh), 20, &hd_qthresh_handler, "IU", "queueing congestion threshold (qth) in ticks"); SYSCTL_VNET_PROC(_net_inet_tcp_cc_hd, OID_AUTO, pmax, CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(hd_pmax), 5, &hd_pmax_handler, "IU", "per packet maximum backoff probability as a percentage"); SYSCTL_VNET_PROC(_net_inet_tcp_cc_hd, OID_AUTO, queue_min, 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);