cc.h

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/*-
 * Copyright (c) 2007-2008
 *      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 and
 * James Healy, 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.
 *
 * $FreeBSD$
 */
 
/*
 * 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/
 */
 
#ifndef _NETINET_CC_CC_H_
#define _NETINET_CC_CC_H_
 
#ifdef _KERNEL
 
MALLOC_DECLARE(M_CC_MEM);
 
/* Global CC vars. */
extern STAILQ_HEAD(cc_head, cc_algo) cc_list;
extern const int tcprexmtthresh;
 
/* Per-netstack bits. */
VNET_DECLARE(struct cc_algo *, default_cc_ptr);
#define V_default_cc_ptr VNET(default_cc_ptr)
 
VNET_DECLARE(int, cc_do_abe);
#define V_cc_do_abe                     VNET(cc_do_abe)
 
VNET_DECLARE(int, cc_abe_frlossreduce);
#define V_cc_abe_frlossreduce           VNET(cc_abe_frlossreduce)
 
/* Define the new net.inet.tcp.cc sysctl tree. */
SYSCTL_DECL(_net_inet_tcp_cc);
 
/* For CC modules that use hystart++ */
extern uint32_t hystart_lowcwnd;
extern uint32_t hystart_minrtt_thresh;
extern uint32_t hystart_maxrtt_thresh;
extern uint32_t hystart_n_rttsamples;
extern uint32_t hystart_css_growth_div;
extern uint32_t hystart_css_rounds;
extern uint32_t hystart_bblogs;
 
/* CC housekeeping functions. */
int     cc_register_algo(struct cc_algo *add_cc);
int     cc_deregister_algo(struct cc_algo *remove_cc);
 
/*
 * Wrapper around transport structs that contain same-named congestion
 * control variables. Allows algos to be shared amongst multiple CC aware
 * transprots.
 */
struct cc_var {
        void            *cc_data; /* Per-connection private CC algorithm data. */
        int             bytes_this_ack; /* # bytes acked by the current ACK. */
        tcp_seq         curack; /* Most recent ACK. */
        uint32_t        flags; /* Flags for cc_var (see below) */
        int             type; /* Indicates which ptr is valid in ccvc. */
        union ccv_container {
                struct tcpcb            *tcp;
                struct sctp_nets        *sctp;
        } ccvc;
        uint16_t        nsegs; /* # segments coalesced into current chain. */
        uint8_t         labc;  /* Dont use system abc use passed in */
};
 
/* cc_var flags. */
#define CCF_ABC_SENTAWND        0x0001  /* ABC counted cwnd worth of bytes? */
#define CCF_CWND_LIMITED        0x0002  /* Are we currently cwnd limited? */
#define CCF_USE_LOCAL_ABC       0x0004  /* Dont use the system l_abc val */
#define CCF_ACKNOW              0x0008  /* Will this ack be sent now? */
#define CCF_IPHDR_CE            0x0010  /* Does this packet set CE bit? */
#define CCF_TCPHDR_CWR          0x0020  /* Does this packet set CWR bit? */
#define CCF_MAX_CWND            0x0040  /* Have we reached maximum cwnd? */
#define CCF_CHG_MAX_CWND        0x0080  /* Cubic max_cwnd changed, for K */
#define CCF_USR_IWND            0x0100  /* User specified initial window */
#define CCF_USR_IWND_INIT_NSEG  0x0200  /* Convert segs to bytes on conn init */
#define CCF_HYSTART_ALLOWED     0x0400  /* If the CC supports it Hystart is allowed */
#define CCF_HYSTART_CAN_SH_CWND 0x0800  /* Can hystart when going CSS -> CA slam the cwnd */
#define CCF_HYSTART_CONS_SSTH   0x1000  /* Should hystart use the more conservative ssthresh */
 
/* ACK types passed to the ack_received() hook. */
#define CC_ACK          0x0001  /* Regular in sequence ACK. */
#define CC_DUPACK       0x0002  /* Duplicate ACK. */
#define CC_PARTIALACK   0x0004  /* Not yet. */
#define CC_SACK         0x0008  /* Not yet. */
#endif /* _KERNEL */
 
/*
 * Congestion signal types passed to the cong_signal() hook. The highest order 8
 * bits (0x01000000 - 0x80000000) are reserved for CC algos to declare their own
 * congestion signal types.
 */
#define CC_ECN          0x00000001      /* ECN marked packet received. */
#define CC_RTO          0x00000002      /* RTO fired. */
#define CC_RTO_ERR      0x00000004      /* RTO fired in error. */
#define CC_NDUPACK      0x00000008      /* Threshold of dupack's reached. */
 
#define CC_SIGPRIVMASK  0xFF000000      /* Mask to check if sig is private. */
 
#ifdef _KERNEL
/*
 * Structure to hold data and function pointers that together represent a
 * congestion control algorithm.
 */
struct cc_algo {
        char    name[TCP_CA_NAME_MAX];
 
        /* Init global module state on kldload. */
        int     (*mod_init)(void);
 
        /* Cleanup global module state on kldunload. */
        int     (*mod_destroy)(void);
 
        /* Return the size of the void pointer the CC needs for state */
        size_t  (*cc_data_sz)(void);
 
        /*
         * Init CC state for a new control block. The CC
         * module may be passed a NULL ptr indicating that
         * it must allocate the memory. If it is passed a
         * non-null pointer it is pre-allocated memory by
         * the caller and the cb_init is expected to use that memory.
         * It is not expected to fail if memory is passed in and
         * all currently defined modules do not.
         */
        int     (*cb_init)(struct cc_var *ccv, void *ptr);
 
        /* Cleanup CC state for a terminating control block. */
        void    (*cb_destroy)(struct cc_var *ccv);
 
        /* Init variables for a newly established connection. */
        void    (*conn_init)(struct cc_var *ccv);
 
        /* Called on receipt of an ack. */
        void    (*ack_received)(struct cc_var *ccv, uint16_t type);
 
        /* Called on detection of a congestion signal. */
        void    (*cong_signal)(struct cc_var *ccv, uint32_t type);
 
        /* Called after exiting congestion recovery. */
        void    (*post_recovery)(struct cc_var *ccv);
 
        /* Called when data transfer resumes after an idle period. */
        void    (*after_idle)(struct cc_var *ccv);
 
        /* Called for an additional ECN processing apart from RFC3168. */
        void    (*ecnpkt_handler)(struct cc_var *ccv);
 
        /* Called when a new "round" begins, if the transport is tracking rounds.  */
        void    (*newround)(struct cc_var *ccv, uint32_t round_cnt);
 
        /*
         *  Called when a RTT sample is made (fas = flight at send, if you dont have it
         *  send the cwnd in).
         */
        void    (*rttsample)(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas);
 
        /* Called for {get|set}sockopt() on a TCP socket with TCP_CCALGOOPT. */
        int     (*ctl_output)(struct cc_var *, struct sockopt *, void *);
 
        STAILQ_ENTRY (cc_algo) entries;
        u_int   cc_refcount;
        uint8_t flags;
};
 
#define CC_MODULE_BEING_REMOVED         0x01    /* The module is being removed */
 
/* Macro to obtain the CC algo's struct ptr. */
#define CC_ALGO(tp)     ((tp)->cc_algo)
 
/* Macro to obtain the CC algo's data ptr. */
#define CC_DATA(tp)     ((tp)->ccv->cc_data)
 
/* Macro to obtain the system default CC algo's struct ptr. */
#define CC_DEFAULT_ALGO()       V_default_cc_ptr
 
extern struct rwlock cc_list_lock;
#define CC_LIST_LOCK_INIT()     rw_init(&cc_list_lock, "cc_list")
#define CC_LIST_LOCK_DESTROY()  rw_destroy(&cc_list_lock)
#define CC_LIST_RLOCK()         rw_rlock(&cc_list_lock)
#define CC_LIST_RUNLOCK()       rw_runlock(&cc_list_lock)
#define CC_LIST_WLOCK()         rw_wlock(&cc_list_lock)
#define CC_LIST_WUNLOCK()       rw_wunlock(&cc_list_lock)
#define CC_LIST_LOCK_ASSERT()   rw_assert(&cc_list_lock, RA_LOCKED)
 
#define CC_ALGOOPT_LIMIT        2048
 
/*
 * These routines give NewReno behavior to the caller
 * they require no state and can be used by any other CC
 * module that wishes to use NewReno type behaviour (along
 * with anything else they may add on, pre or post call).
 */
void newreno_cc_post_recovery(struct cc_var *);
void newreno_cc_after_idle(struct cc_var *);
void newreno_cc_cong_signal(struct cc_var *, uint32_t );
void newreno_cc_ack_received(struct cc_var *, uint16_t);
 
/* Called to temporarily keep an algo from going away during change */
void cc_refer(struct cc_algo *algo);
/* Called to release the temporary hold */
void cc_release(struct cc_algo *algo);
 
/* Called to attach a CC algorithm to a tcpcb */
void cc_attach(struct tcpcb *, struct cc_algo *);
/* Called to detach a CC algorithm from a tcpcb */
void cc_detach(struct tcpcb *);
 
#endif /* _KERNEL */
#endif /* _NETINET_CC_CC_H_ */