FreeBSD/Linux Kernel Cross Reference
sys/netinet/cc/cc.h

     /*-
      * 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. */
    #ifdef _SYS_SYSCTL_H_
    SYSCTL_DECL(_net_inet_tcp_cc);
    #endif
    
    /* 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);
    #endif /* _KERNEL */
    
    #if defined(_KERNEL) || defined(_WANT_TCPCB)
    /*
     * 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 /* defined(_KERNEL) || defined(_WANT_TCPCB) */
   
   /*
    * 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)->t_cc)
   
   /* Macro to obtain the CC algo's data ptr. */
   #define CC_DATA(tp)     ((tp)->t_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_ */

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