diff options
Diffstat (limited to 'freebsd/sys/netinet/cc/cc_newreno.c')
| -rw-r--r-- | freebsd/sys/netinet/cc/cc_newreno.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/freebsd/sys/netinet/cc/cc_newreno.c b/freebsd/sys/netinet/cc/cc_newreno.c new file mode 100644 index 00000000..e40f6d83 --- /dev/null +++ b/freebsd/sys/netinet/cc/cc_newreno.c @@ -0,0 +1,239 @@ +#include <machine/rtems-bsd-config.h> + +/*- + * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995 + * The Regents of the University of California. + * Copyright (c) 2007-2008,2010 + * Swinburne University of Technology, Melbourne, Australia. + * Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org> + * Copyright (c) 2010 The FreeBSD Foundation + * All rights reserved. + * + * This software was developed at the Centre for Advanced Internet + * Architectures, Swinburne University of Technology, by Lawrence Stewart, James + * Healy and David Hayes, 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. + */ + +/* + * This software was first released in 2007 by James Healy and Lawrence Stewart + * whilst working on 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 <rtems/bsd/sys/param.h> +#include <sys/kernel.h> +#include <sys/malloc.h> +#include <sys/module.h> +#include <sys/socket.h> +#include <sys/socketvar.h> +#include <sys/sysctl.h> +#include <sys/systm.h> + +#include <net/vnet.h> + +#include <netinet/cc.h> +#include <netinet/tcp_seq.h> +#include <netinet/tcp_var.h> + +#include <netinet/cc/cc_module.h> + +static void newreno_ack_received(struct cc_var *ccv, uint16_t type); +static void newreno_after_idle(struct cc_var *ccv); +static void newreno_cong_signal(struct cc_var *ccv, uint32_t type); +static void newreno_post_recovery(struct cc_var *ccv); + +struct cc_algo newreno_cc_algo = { + .name = "newreno", + .ack_received = newreno_ack_received, + .after_idle = newreno_after_idle, + .cong_signal = newreno_cong_signal, + .post_recovery = newreno_post_recovery, +}; + +static void +newreno_ack_received(struct cc_var *ccv, uint16_t type) +{ + if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && + (ccv->flags & CCF_CWND_LIMITED)) { + u_int cw = CCV(ccv, snd_cwnd); + u_int incr = CCV(ccv, t_maxseg); + + /* + * Regular in-order ACK, open the congestion window. + * Method depends on which congestion control state we're + * in (slow start or cong avoid) and if ABC (RFC 3465) is + * enabled. + * + * slow start: cwnd <= ssthresh + * cong avoid: cwnd > ssthresh + * + * slow start and ABC (RFC 3465): + * Grow cwnd exponentially by the amount of data + * ACKed capping the max increment per ACK to + * (abc_l_var * maxseg) bytes. + * + * slow start without ABC (RFC 5681): + * Grow cwnd exponentially by maxseg per ACK. + * + * cong avoid and ABC (RFC 3465): + * Grow cwnd linearly by maxseg per RTT for each + * cwnd worth of ACKed data. + * + * cong avoid without ABC (RFC 5681): + * Grow cwnd linearly by approximately maxseg per RTT using + * maxseg^2 / cwnd per ACK as the increment. + * If cwnd > maxseg^2, fix the cwnd increment at 1 byte to + * avoid capping cwnd. + */ + if (cw > CCV(ccv, snd_ssthresh)) { + if (V_tcp_do_rfc3465) { + if (ccv->flags & CCF_ABC_SENTAWND) + ccv->flags &= ~CCF_ABC_SENTAWND; + else + incr = 0; + } else + incr = max((incr * incr / cw), 1); + } else if (V_tcp_do_rfc3465) { + /* + * In slow-start with ABC enabled and no RTO in sight? + * (Must not use abc_l_var > 1 if slow starting after + * an RTO. On RTO, snd_nxt = snd_una, so the + * snd_nxt == snd_max check is sufficient to + * handle this). + * + * XXXLAS: Find a way to signal SS after RTO that + * doesn't rely on tcpcb vars. + */ + if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max)) + incr = min(ccv->bytes_this_ack, + V_tcp_abc_l_var * CCV(ccv, t_maxseg)); + else + incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); + } + /* ABC is on by default, so incr equals 0 frequently. */ + if (incr > 0) + CCV(ccv, snd_cwnd) = min(cw + incr, + TCP_MAXWIN << CCV(ccv, snd_scale)); + } +} + +static void +newreno_after_idle(struct cc_var *ccv) +{ + int rw; + + /* + * If we've been idle for more than one retransmit timeout the old + * congestion window is no longer current and we have to reduce it to + * the restart window before we can transmit again. + * + * The restart window is the initial window or the last CWND, whichever + * is smaller. + * + * This is done to prevent us from flooding the path with a full CWND at + * wirespeed, overloading router and switch buffers along the way. + * + * See RFC5681 Section 4.1. "Restarting Idle Connections". + */ + if (V_tcp_do_rfc3390) + rw = min(4 * CCV(ccv, t_maxseg), + max(2 * CCV(ccv, t_maxseg), 4380)); + else + rw = CCV(ccv, t_maxseg) * 2; + + CCV(ccv, snd_cwnd) = min(rw, CCV(ccv, snd_cwnd)); +} + +/* + * Perform any necessary tasks before we enter congestion recovery. + */ +static void +newreno_cong_signal(struct cc_var *ccv, uint32_t type) +{ + u_int win; + + /* Catch algos which mistakenly leak private signal types. */ + KASSERT((type & CC_SIGPRIVMASK) == 0, + ("%s: congestion signal type 0x%08x is private\n", __func__, type)); + + win = max(CCV(ccv, snd_cwnd) / 2 / CCV(ccv, t_maxseg), 2) * + CCV(ccv, t_maxseg); + + switch (type) { + case CC_NDUPACK: + if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { + if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) + CCV(ccv, snd_ssthresh) = win; + ENTER_RECOVERY(CCV(ccv, t_flags)); + } + break; + case CC_ECN: + if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { + CCV(ccv, snd_ssthresh) = win; + CCV(ccv, snd_cwnd) = win; + ENTER_CONGRECOVERY(CCV(ccv, t_flags)); + } + break; + } +} + +/* + * Perform any necessary tasks before we exit congestion recovery. + */ +static void +newreno_post_recovery(struct cc_var *ccv) +{ + if (IN_FASTRECOVERY(CCV(ccv, t_flags))) { + /* + * Fast recovery will conclude after returning from this + * function. Window inflation should have left us with + * approximately snd_ssthresh outstanding data. But in case we + * would be inclined to send a burst, better to do it via the + * slow start mechanism. + * + * XXXLAS: Find a way to do this without needing curack + */ + if (SEQ_GT(ccv->curack + CCV(ccv, snd_ssthresh), + CCV(ccv, snd_max))) + CCV(ccv, snd_cwnd) = CCV(ccv, snd_max) - + ccv->curack + CCV(ccv, t_maxseg); + else + CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh); + } +} + + +DECLARE_CC_MODULE(newreno, &newreno_cc_algo); |