diff options
Diffstat (limited to 'sys/netinet/cc')
-rw-r--r-- | sys/netinet/cc/cc_hd.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/sys/netinet/cc/cc_hd.c b/sys/netinet/cc/cc_hd.c new file mode 100644 index 0000000..b33fb2c --- /dev/null +++ b/sys/netinet/cc/cc_hd.c @@ -0,0 +1,254 @@ +/*- + * 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, 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'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/if.h> +#include <net/vnet.h> + +#include <netinet/cc.h> +#include <netinet/tcp_seq.h> +#include <netinet/tcp_timer.h> +#include <netinet/tcp_var.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_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); |