64807b300f
DCTCP congestion control algorithm aims to maximise throughput and minimise latency in data center networks by utilising the proportion of Explicit Congestion Notification (ECN) marked packets received from capable hardware as a congestion signal. Highlights: Implemented as a mod_cc(4) module. ECN (Explicit congestion notification) processing is done differently from RFC3168. Takes one-sided DCTCP into consideration where only one of the sides is using DCTCP and other is using standard ECN. IETF draft: http://tools.ietf.org/html/draft-bensley-tcpm-dctcp-00 Thesis report by Midori Kato: https://eggert.org/students/kato-thesis.pdf Submitted by: Midori Kato <katoon@sfc.wide.ad.jp> and Lars Eggert <lars@netapp.com> with help and modifications from hiren Differential Revision: https://reviews.freebsd.org/D604 Reviewed by: gnn
175 lines
6.5 KiB
C
175 lines
6.5 KiB
C
/*-
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* Copyright (c) 2007-2008
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* Swinburne University of Technology, Melbourne, Australia.
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* Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org>
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* Copyright (c) 2010 The FreeBSD Foundation
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* All rights reserved.
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*
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* This software was developed at the Centre for Advanced Internet
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* Architectures, Swinburne University of Technology, by Lawrence Stewart and
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* James Healy, made possible in part by a grant from the Cisco University
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* Research Program Fund at Community Foundation Silicon Valley.
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*
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* Portions of this software were developed at the Centre for Advanced
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* Internet Architectures, Swinburne University of Technology, Melbourne,
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* Australia by David Hayes under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* This software was first released in 2007 by James Healy and Lawrence Stewart
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* whilst working on the NewTCP research project at Swinburne University of
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* Technology's Centre for Advanced Internet Architectures, Melbourne,
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* Australia, which was made possible in part by a grant from the Cisco
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* University Research Program Fund at Community Foundation Silicon Valley.
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* More details are available at:
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* http://caia.swin.edu.au/urp/newtcp/
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*/
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#ifndef _NETINET_CC_H_
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#define _NETINET_CC_H_
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/* XXX: TCP_CA_NAME_MAX define lives in tcp.h for compat reasons. */
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#include <netinet/tcp.h>
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/* Global CC vars. */
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extern STAILQ_HEAD(cc_head, cc_algo) cc_list;
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extern const int tcprexmtthresh;
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extern struct cc_algo newreno_cc_algo;
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/* Per-netstack bits. */
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VNET_DECLARE(struct cc_algo *, default_cc_ptr);
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#define V_default_cc_ptr VNET(default_cc_ptr)
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/* Define the new net.inet.tcp.cc sysctl tree. */
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SYSCTL_DECL(_net_inet_tcp_cc);
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/* CC housekeeping functions. */
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int cc_register_algo(struct cc_algo *add_cc);
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int cc_deregister_algo(struct cc_algo *remove_cc);
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/*
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* Wrapper around transport structs that contain same-named congestion
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* control variables. Allows algos to be shared amongst multiple CC aware
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* transprots.
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*/
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struct cc_var {
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void *cc_data; /* Per-connection private CC algorithm data. */
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int bytes_this_ack; /* # bytes acked by the current ACK. */
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tcp_seq curack; /* Most recent ACK. */
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uint32_t flags; /* Flags for cc_var (see below) */
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int type; /* Indicates which ptr is valid in ccvc. */
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union ccv_container {
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struct tcpcb *tcp;
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struct sctp_nets *sctp;
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} ccvc;
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};
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/* cc_var flags. */
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#define CCF_ABC_SENTAWND 0x0001 /* ABC counted cwnd worth of bytes? */
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#define CCF_CWND_LIMITED 0x0002 /* Are we currently cwnd limited? */
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#define CCF_DELACK 0x0004 /* Is this ack delayed? */
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#define CCF_ACKNOW 0x0008 /* Will this ack be sent now? */
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#define CCF_IPHDR_CE 0x0010 /* Does this packet set CE bit? */
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#define CCF_TCPHDR_CWR 0x0020 /* Does this packet set CWR bit? */
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/* ACK types passed to the ack_received() hook. */
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#define CC_ACK 0x0001 /* Regular in sequence ACK. */
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#define CC_DUPACK 0x0002 /* Duplicate ACK. */
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#define CC_PARTIALACK 0x0004 /* Not yet. */
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#define CC_SACK 0x0008 /* Not yet. */
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/*
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* Congestion signal types passed to the cong_signal() hook. The highest order 8
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* bits (0x01000000 - 0x80000000) are reserved for CC algos to declare their own
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* congestion signal types.
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*/
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#define CC_ECN 0x00000001 /* ECN marked packet received. */
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#define CC_RTO 0x00000002 /* RTO fired. */
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#define CC_RTO_ERR 0x00000004 /* RTO fired in error. */
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#define CC_NDUPACK 0x00000008 /* Threshold of dupack's reached. */
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#define CC_SIGPRIVMASK 0xFF000000 /* Mask to check if sig is private. */
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/*
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* Structure to hold data and function pointers that together represent a
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* congestion control algorithm.
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*/
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struct cc_algo {
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char name[TCP_CA_NAME_MAX];
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/* Init global module state on kldload. */
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int (*mod_init)(void);
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/* Cleanup global module state on kldunload. */
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int (*mod_destroy)(void);
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/* Init CC state for a new control block. */
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int (*cb_init)(struct cc_var *ccv);
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/* Cleanup CC state for a terminating control block. */
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void (*cb_destroy)(struct cc_var *ccv);
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/* Init variables for a newly established connection. */
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void (*conn_init)(struct cc_var *ccv);
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/* Called on receipt of an ack. */
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void (*ack_received)(struct cc_var *ccv, uint16_t type);
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/* Called on detection of a congestion signal. */
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void (*cong_signal)(struct cc_var *ccv, uint32_t type);
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/* Called after exiting congestion recovery. */
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void (*post_recovery)(struct cc_var *ccv);
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/* Called when data transfer resumes after an idle period. */
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void (*after_idle)(struct cc_var *ccv);
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/* Called for an additional ECN processing apart from RFC3168. */
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void (*ecnpkt_handler)(struct cc_var *ccv);
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STAILQ_ENTRY (cc_algo) entries;
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};
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/* Macro to obtain the CC algo's struct ptr. */
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#define CC_ALGO(tp) ((tp)->cc_algo)
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/* Macro to obtain the CC algo's data ptr. */
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#define CC_DATA(tp) ((tp)->ccv->cc_data)
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/* Macro to obtain the system default CC algo's struct ptr. */
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#define CC_DEFAULT() V_default_cc_ptr
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extern struct rwlock cc_list_lock;
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#define CC_LIST_LOCK_INIT() rw_init(&cc_list_lock, "cc_list")
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#define CC_LIST_LOCK_DESTROY() rw_destroy(&cc_list_lock)
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#define CC_LIST_RLOCK() rw_rlock(&cc_list_lock)
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#define CC_LIST_RUNLOCK() rw_runlock(&cc_list_lock)
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#define CC_LIST_WLOCK() rw_wlock(&cc_list_lock)
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#define CC_LIST_WUNLOCK() rw_wunlock(&cc_list_lock)
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#define CC_LIST_LOCK_ASSERT() rw_assert(&cc_list_lock, RA_LOCKED)
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#endif /* _NETINET_CC_H_ */
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