tcp_rack.h

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/*-
 * Copyright (c) 2016-2020 Netflix, Inc.
 *
 * 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 REGENTS 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 REGENTS 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.
 *
 * $FreeBSD$
 */
 
#ifndef _NETINET_TCP_RACK_H_
#define _NETINET_TCP_RACK_H_
 
#define RACK_ACKED          0x000001/* The remote endpoint acked this */
#define RACK_TO_REXT        0x000002/* A timeout occured on this sendmap entry */
#define RACK_DEFERRED       0x000004/* We can't use this for RTT calc - not used */
#define RACK_OVERMAX        0x000008/* We have more retran's then we can fit */
#define RACK_SACK_PASSED    0x000010/* A sack was done above this block */
#define RACK_WAS_SACKPASS   0x000020/* We retransmitted due to SACK pass */
#define RACK_HAS_FIN        0x000040/* segment is sent with fin */
#define RACK_TLP            0x000080/* segment sent as tail-loss-probe */
#define RACK_RWND_COLLAPSED 0x000100/* The peer collapsed the rwnd on the segment */
#define RACK_APP_LIMITED    0x000200/* We went app limited after this send */
#define RACK_WAS_ACKED      0x000400/* a RTO undid the ack, but it already had a rtt calc done */
#define RACK_HAS_SYN        0x000800/* SYN is on this guy */
#define RACK_SENT_W_DSACK   0x001000/* Sent with a dsack */
#define RACK_SENT_SP        0x002000/* sent in slow path */
#define RACK_SENT_FP        0x004000/* sent in fast path */
#define RACK_HAD_PUSH       0x008000/* Push was sent on original send */
#define RACK_MUST_RXT       0x010000/* We must retransmit this rsm (non-sack/mtu chg)*/
#define RACK_NUM_OF_RETRANS 3
 
#define RACK_INITIAL_RTO 1000000 /* 1 second in microseconds */
 
#define RACK_REQ_AVG 3  /* Must be less than 256 */
 
struct rack_sendmap {
        TAILQ_ENTRY(rack_sendmap) r_tnext;      /* Time of transmit based next */
        uint32_t r_start;       /* Sequence number of the segment */
        uint32_t r_end;         /* End seq, this is 1 beyond actually */
        uint32_t r_rtr_bytes;   /* How many bytes have been retransmitted */
        uint32_t r_flags : 24,  /* Flags as defined above */
                 r_rtr_cnt : 8; /* Retran count, index this -1 to get time */
        struct mbuf *m;
        uint32_t soff;
        uint32_t orig_m_len;
        uint32_t r_nseq_appl;   /* If this one is app limited, this is the nxt seq limited */
        uint8_t r_dupack;       /* Dup ack count */
        uint8_t r_in_tmap;      /* Flag to see if its in the r_tnext array */
        uint8_t r_limit_type;   /* is this entry counted against a limit? */
        uint8_t r_just_ret : 1, /* After sending, the next pkt was just returned, i.e. limited  */
                r_one_out_nr : 1,       /* Special case 1 outstanding and not in recovery */
                r_no_rtt_allowed : 1, /* No rtt measurement allowed */
                r_hw_tls : 1,
                r_avail : 4;
        uint64_t r_tim_lastsent[RACK_NUM_OF_RETRANS];
        uint64_t r_ack_arrival; /* This is the time of ack-arrival (if SACK'd) */
        RB_ENTRY(rack_sendmap) r_next;          /* RB Tree next */
        uint32_t r_fas;         /* Flight at send */
};
 
struct deferred_opt_list {
        TAILQ_ENTRY(deferred_opt_list) next;
        int optname;
        uint64_t optval;
};
 
/*
 * Timestamps in the rack sendmap are now moving to be
 * uint64_t's. This means that if you want a uint32_t
 * usec timestamp (the old usecond timestamp) you simply have
 * to cast it to uint32_t. The reason we do this is not for
 * wrap, but we need to get back, at times, to the millisecond
 * timestamp that is used in the TSTMP option. To do this we
 * can use the rack_ts_to_msec() inline below which can take
 * the 64bit ts and make into the correct timestamp millisecond
 * wise. Thats not possible with the 32bit usecond timestamp since
 * the seconds wrap too quickly to cover all bases.
 *
 * There are quite a few places in rack where I simply cast
 * back to uint32_t and then end up using the TSTMP_XX()
 * macros. This is ok, but we could do simple compares if
 * we ever decided to move all of those variables to 64 bits
 * as well.
 */
 
inline uint64_t
rack_to_usec_ts(struct timeval *tv)
{
        return ((tv->tv_sec * HPTS_USEC_IN_SEC) + tv->tv_usec);
}
 
inline uint32_t
rack_ts_to_msec(uint64_t ts)
{
        return((uint32_t)(ts / HPTS_MSEC_IN_SEC));
}
 
 
RB_HEAD(rack_rb_tree_head, rack_sendmap);
TAILQ_HEAD(rack_head, rack_sendmap);
TAILQ_HEAD(def_opt_head, deferred_opt_list);
 
/* Map change logging */
#define MAP_MERGE       0x01
#define MAP_SPLIT       0x02
#define MAP_NEW         0x03
#define MAP_SACK_M1     0x04
#define MAP_SACK_M2     0x05
#define MAP_SACK_M3     0x06
#define MAP_SACK_M4     0x07
#define MAP_SACK_M5     0x08
#define MAP_FREE        0x09
#define MAP_TRIM_HEAD   0x0a
 
#define RACK_LIMIT_TYPE_SPLIT   1
 
/*
 * We use the rate sample structure to
 * assist in single sack/ack rate and rtt
 * calculation. In the future we will expand
 * this in BBR to do forward rate sample
 * b/w estimation.
 */
#define RACK_RTT_EMPTY 0x00000001       /* Nothing yet stored in RTT's */
#define RACK_RTT_VALID 0x00000002       /* We have at least one valid RTT */
struct rack_rtt_sample {
        uint32_t rs_flags;
        uint32_t rs_rtt_lowest;
        uint32_t rs_rtt_highest;
        uint32_t rs_rtt_cnt;
        uint32_t rs_us_rtt;
        int32_t  confidence;
        uint64_t rs_rtt_tot;
        uint16_t rs_us_rtrcnt;
};
 
#define RACK_LOG_TYPE_ACK       0x01
#define RACK_LOG_TYPE_OUT       0x02
#define RACK_LOG_TYPE_TO        0x03
#define RACK_LOG_TYPE_ALLOC     0x04
#define RACK_LOG_TYPE_FREE      0x05
 
/*
 * Magic numbers for logging timeout events if the
 * logging is enabled.
 */
#define RACK_TO_FRM_TMR  1
#define RACK_TO_FRM_TLP  2
#define RACK_TO_FRM_RACK 3
#define RACK_TO_FRM_KEEP 4
#define RACK_TO_FRM_PERSIST 5
#define RACK_TO_FRM_DELACK 6
 
struct rack_opts_stats {
        uint64_t tcp_rack_tlp_reduce;
        uint64_t tcp_rack_pace_always;
        uint64_t tcp_rack_pace_reduce;
        uint64_t tcp_rack_max_seg;
        uint64_t tcp_rack_prr_sendalot;
        uint64_t tcp_rack_min_to;
        uint64_t tcp_rack_early_seg;
        uint64_t tcp_rack_reord_thresh;
        uint64_t tcp_rack_reord_fade;
        uint64_t tcp_rack_tlp_thresh;
        uint64_t tcp_rack_pkt_delay;
        uint64_t tcp_rack_tlp_inc_var;
        uint64_t tcp_tlp_use;
        uint64_t tcp_rack_idle_reduce;
        uint64_t tcp_rack_idle_reduce_high;
        uint64_t rack_no_timer_in_hpts;
        uint64_t tcp_rack_min_pace_seg;
        uint64_t tcp_rack_pace_rate_ca;
        uint64_t tcp_rack_rr;
        uint64_t tcp_rack_do_detection;
        uint64_t tcp_rack_rrr_no_conf_rate;
        uint64_t tcp_initial_rate;
        uint64_t tcp_initial_win;
        uint64_t tcp_hdwr_pacing;
        uint64_t tcp_gp_inc_ss;
        uint64_t tcp_gp_inc_ca;
        uint64_t tcp_gp_inc_rec;
        uint64_t tcp_rack_force_max_seg;
        uint64_t tcp_rack_pace_rate_ss;
        uint64_t tcp_rack_pace_rate_rec;
        /* Temp counters for dsack */
        uint64_t tcp_sack_path_1;
        uint64_t tcp_sack_path_2a;
        uint64_t tcp_sack_path_2b;
        uint64_t tcp_sack_path_3;
        uint64_t tcp_sack_path_4;
        /* non temp counters */
        uint64_t tcp_rack_scwnd;
        uint64_t tcp_rack_noprr;
        uint64_t tcp_rack_cfg_rate;
        uint64_t tcp_timely_dyn;
        uint64_t tcp_rack_mbufq;
        uint64_t tcp_fillcw;
        uint64_t tcp_npush;
        uint64_t tcp_lscwnd;
        uint64_t tcp_profile;
        uint64_t tcp_hdwr_rate_cap;
        uint64_t tcp_pacing_rate_cap;
        uint64_t tcp_pacing_up_only;
        uint64_t tcp_use_cmp_acks;
        uint64_t tcp_rack_abc_val;
        uint64_t tcp_rec_abc_val;
        uint64_t tcp_rack_measure_cnt;
        uint64_t tcp_rack_delayed_ack;
        uint64_t tcp_rack_rtt_use;
        uint64_t tcp_data_after_close;
        uint64_t tcp_defer_opt;
        uint64_t tcp_rack_fastrsm_hack;
        uint64_t tcp_rack_beta;
        uint64_t tcp_rack_beta_ecn;
        uint64_t tcp_rack_timer_slop;
        uint64_t tcp_rack_dsack_opt;
};
 
/* RTT shrink reasons */
#define RACK_RTTS_INIT     0
#define RACK_RTTS_NEWRTT   1
#define RACK_RTTS_EXITPROBE 2
#define RACK_RTTS_ENTERPROBE 3
#define RACK_RTTS_REACHTARGET 4
#define RACK_RTTS_SEEHBP 5
#define RACK_RTTS_NOBACKOFF 6
#define RACK_RTTS_SAFETY 7
 
#define RACK_USE_BEG 1
#define RACK_USE_END 2
#define RACK_USE_END_OR_THACK 3
 
#define TLP_USE_ID      1       /* Internet draft behavior */
#define TLP_USE_TWO_ONE 2       /* Use 2.1 behavior */
#define TLP_USE_TWO_TWO 3       /* Use 2.2 behavior */
#define RACK_MIN_BW 8000        /* 64kbps in Bps */
 
/* Rack quality indicators for GPUT measurements */
#define RACK_QUALITY_NONE       0       /* No quality stated */
#define RACK_QUALITY_HIGH       1       /* A normal measurement of a GP RTT */
#define RACK_QUALITY_APPLIMITED 2       /* An app limited case that may be of lower quality */
#define RACK_QUALITY_PERSIST    3       /* A measurement where we went into persists */
#define RACK_QUALITY_PROBERTT   4       /* A measurement where we went into or exited probe RTT */
#define RACK_QUALITY_ALLACKED   5       /* All data is now acknowledged */
 
 
#define MIN_GP_WIN 6    /* We need at least 6 MSS in a GP measurement */
#ifdef _KERNEL
#define RACK_OPTS_SIZE (sizeof(struct rack_opts_stats)/sizeof(uint64_t))
extern counter_u64_t rack_opts_arry[RACK_OPTS_SIZE];
#define RACK_OPTS_ADD(name, amm) counter_u64_add(rack_opts_arry[(offsetof(struct rack_opts_stats, name)/sizeof(uint64_t))], (amm))
#define RACK_OPTS_INC(name) RACK_OPTS_ADD(name, 1)
#endif
/*
 * As we get each SACK we wade through the
 * rc_map and mark off what is acked.
 * We also increment rc_sacked as well.
 *
 * We also pay attention to missing entries
 * based on the time and possibly mark them
 * for retransmit. If we do and we are not already
 * in recovery we enter recovery. In doing
 * so we claer prr_delivered/holes_rxt and prr_sent_dur_rec.
 * We also setup rc_next/rc_snd_nxt/rc_send_end so
 * we will know where to send from. When not in
 * recovery rc_next will be NULL and rc_snd_nxt should
 * equal snd_max.
 *
 * Whenever we retransmit from recovery we increment
 * rc_holes_rxt as we retran a block and mark it as retransmitted
 * with the time it was sent. During non-recovery sending we
 * add to our map and note the time down of any send expanding
 * the rc_map at the tail and moving rc_snd_nxt up with snd_max.
 *
 * In recovery during SACK/ACK processing if a chunk has
 * been retransmitted and it is now acked, we decrement rc_holes_rxt.
 * When we retransmit from the scoreboard we use
 * rc_next and rc_snd_nxt/rc_send_end to help us
 * find what needs to be retran.
 *
 * To calculate pipe we simply take (snd_max - snd_una) + rc_holes_rxt
 * This gets us the effect of RFC6675 pipe, counting twice for
 * bytes retransmitted.
 */
 
#define TT_RACK_FR_TMR  0x2000
 
/*
 * Locking for the rack control block.
 * a) Locked by INP_WLOCK
 * b) Locked by the hpts-mutex
 *
 */
#define RACK_GP_HIST 4  /* How much goodput history do we maintain? */
 
#define RACK_NUM_FSB_DEBUG 16
#ifdef _KERNEL
struct rack_fast_send_blk {
        uint32_t left_to_send;
        uint16_t tcp_ip_hdr_len;
        uint8_t tcp_flags;
        uint8_t hoplimit;
        uint8_t *tcp_ip_hdr;
        uint32_t recwin;
        uint32_t off;
        struct tcphdr *th;
        struct udphdr *udp;
        struct mbuf *m;
        uint32_t o_m_len;
        uint32_t rfo_apply_push : 1,
                hw_tls : 1,
                unused : 30;
};
 
struct rack_control {
        /* Second cache line 0x40 from tcp_rack */
        struct rack_rb_tree_head rc_mtree; /* Tree of all segments Lock(a) */
        struct rack_head rc_tmap;       /* List in transmit order Lock(a) */
        struct rack_sendmap *rc_tlpsend;        /* Remembered place for
                                                 * tlp_sending Lock(a) */
        struct rack_sendmap *rc_resend; /* something we have been asked to
                                         * resend */
        struct rack_fast_send_blk fsb;  /* The fast-send block */
        uint32_t timer_slop;
        uint32_t input_pkt;
        uint32_t saved_input_pkt;
        uint32_t rc_hpts_flags;
        uint32_t rc_fixed_pacing_rate_ca;
        uint32_t rc_fixed_pacing_rate_rec;
        uint32_t rc_fixed_pacing_rate_ss;
        uint32_t cwnd_to_use;   /* The cwnd in use */
        uint32_t rc_timer_exp;  /* If a timer ticks of expiry */
        uint32_t rc_rack_min_rtt;       /* lowest RTT seen Lock(a) */
        uint32_t rc_rack_largest_cwnd;  /* Largest CWND we have seen Lock(a) */
 
        /* Third Cache line 0x80 */
        struct rack_head rc_free;       /* Allocation array */
        uint64_t last_hw_bw_req;
        uint64_t crte_prev_rate;
        uint64_t bw_rate_cap;
        uint32_t rc_reorder_ts; /* Last time we saw reordering Lock(a) */
 
        uint32_t rc_tlp_new_data;       /* we need to send new-data on a TLP
                                         * Lock(a) */
        uint32_t rc_prr_out;    /* bytes sent during recovery Lock(a) */
 
        uint32_t rc_prr_recovery_fs;    /* recovery fs point Lock(a) */
 
        uint32_t rc_prr_sndcnt; /* Prr sndcnt Lock(a) */
 
        uint32_t rc_sacked;     /* Tot sacked on scoreboard Lock(a) */
        uint32_t last_sent_tlp_seq;     /* Last tlp sequence that was retransmitted Lock(a) */
 
        uint32_t rc_prr_delivered;      /* during recovery prr var Lock(a) */
        uint16_t rc_tlp_cnt_out;        /* count of times we have sent a TLP without new data */
        uint16_t last_sent_tlp_len;     /* Number of bytes in the last sent tlp */
 
        uint32_t rc_loss_count; /* How many bytes have been retransmitted
                                 * Lock(a) */
        uint32_t rc_reorder_fade;       /* Socket option value Lock(a) */
 
        /* Forth cache line 0xc0  */
        /* Times */
 
        uint32_t rc_rack_tmit_time;     /* Rack transmit time Lock(a) */
        uint32_t rc_holes_rxt;  /* Tot retraned from scoreboard Lock(a) */
 
        uint32_t rc_num_maps_alloced;   /* Number of map blocks (sacks) we
                                         * have allocated */
        uint32_t rc_rcvtime;    /* When we last received data */
        uint32_t rc_num_split_allocs;   /* num split map entries allocated */
 
        uint32_t rc_last_output_to;
        uint32_t rc_went_idle_time;
 
        struct rack_sendmap *rc_sacklast;       /* sack remembered place
                                                 * Lock(a) */
 
        struct rack_sendmap *rc_first_appl;     /* Pointer to first app limited */
        struct rack_sendmap *rc_end_appl;       /* Pointer to last app limited */
        /* Cache line split 0x100 */
        struct sack_filter rack_sf;
        /* Cache line split 0x140 */
        /* Flags for various things */
        uint32_t rc_pace_max_segs;
        uint32_t rc_pace_min_segs;
        uint32_t rc_app_limited_cnt;
        uint16_t rack_per_of_gp_ss; /* 100 = 100%, so from 65536 = 655 x bw  */
        uint16_t rack_per_of_gp_ca; /* 100 = 100%, so from 65536 = 655 x bw  */
        uint16_t rack_per_of_gp_rec; /* 100 = 100%, so from 65536 = 655 x bw, 0=off */
        uint16_t rack_per_of_gp_probertt; /* 100 = 100%, so from 65536 = 655 x bw, 0=off */
        uint32_t rc_high_rwnd;
        uint32_t ack_count;
        uint32_t sack_count;
        uint32_t sack_noextra_move;
        uint32_t sack_moved_extra;
        struct rack_rtt_sample rack_rs;
        const struct tcp_hwrate_limit_table *crte;
        uint32_t rc_agg_early;
        uint32_t rc_agg_delayed;
        uint32_t rc_tlp_rxt_last_time;
        uint32_t rc_saved_cwnd;
        uint64_t rc_gp_output_ts; /* chg*/
        uint64_t rc_gp_cumack_ts; /* chg*/
        struct timeval act_rcv_time;
        struct timeval rc_last_time_decay;      /* SAD time decay happened here */
        uint64_t gp_bw;
        uint64_t init_rate;
#ifdef NETFLIX_SHARED_CWND
        struct shared_cwnd *rc_scw;
#endif
        uint64_t last_gp_comp_bw;
        uint64_t last_max_bw;   /* Our calculated max b/w last */
        struct time_filter_small rc_gp_min_rtt;
        struct def_opt_head opt_list;
        int32_t rc_rtt_diff;            /* Timely style rtt diff of our gp_srtt */
        uint32_t rc_gp_srtt;            /* Current GP srtt */
        uint32_t rc_prev_gp_srtt;       /* Previous RTT */
        uint32_t rc_entry_gp_rtt;       /* Entry to PRTT gp-rtt */
        uint32_t rc_loss_at_start;      /* At measurement window where was our lost value */
 
        uint32_t dsack_round_end;       /* In a round of seeing a DSACK */
        uint32_t current_round;         /* Starting at zero */
        uint32_t roundends;             /* acked value above which round ends */
        uint32_t num_dsack;             /* Count of dsack's seen  (1 per window)*/
        uint32_t forced_ack_ts;
        uint32_t rc_lower_rtt_us_cts;   /* Time our GP rtt was last lowered */
        uint32_t rc_time_probertt_entered;
        uint32_t rc_time_probertt_starts;
        uint32_t rc_lowest_us_rtt;
        uint32_t rc_highest_us_rtt;
        uint32_t rc_last_us_rtt;
        uint32_t rc_time_of_last_probertt;
        uint32_t rc_target_probertt_flight;
        uint32_t rc_probertt_sndmax_atexit;     /* Highest sent to in probe-rtt */
        uint32_t rc_cwnd_at_erec;
        uint32_t rc_ssthresh_at_erec;
        uint32_t dsack_byte_cnt;
        uint32_t retran_during_recovery;
        uint32_t rc_gp_lowrtt;                  /* Lowest rtt seen during GPUT measurement */
        uint32_t rc_gp_high_rwnd;               /* Highest rwnd seen during GPUT measurement */
        uint32_t rc_snd_max_at_rto;     /* For non-sack when the RTO occured what was snd-max */
        uint32_t rc_out_at_rto;
        int32_t rc_scw_index;
        uint32_t rc_tlp_threshold;      /* Socket option value Lock(a) */
        uint32_t rc_last_timeout_snduna;
        uint32_t last_tlp_acked_start;
        uint32_t last_tlp_acked_end;
        uint32_t challenge_ack_ts;
        uint32_t challenge_ack_cnt;
        uint32_t rc_min_to;     /* Socket option value Lock(a) */
        uint32_t rc_pkt_delay;  /* Socket option value Lock(a) */
        uint32_t persist_lost_ends;
        struct newreno rc_saved_beta;   /*
                                         * For newreno cc:
                                         * rc_saved_cc are the values we have had
                                         * set by the user, if pacing is not happening
                                         * (i.e. its early and we have not turned on yet
                                         *  or it was turned off). The minute pacing
                                         * is turned on we pull out the values currently
                                         * being used by newreno and replace them with
                                         * these values, then save off the old values here,
                                         * we also set the flag (if ecn_beta is set) to make
                                         * new_reno do less of a backoff for ecn (think abe).
                                         */
        uint16_t rc_early_recovery_segs;        /* Socket option value Lock(a) */
        uint16_t rc_reorder_shift;      /* Socket option value Lock(a) */
        uint8_t dsack_persist;
        uint8_t rc_no_push_at_mrtt;     /* No push when we exceed max rtt */
        uint8_t num_measurements;       /* Number of measurements (up to 0xff, we freeze at 0xff)  */
        uint8_t req_measurements;       /* How many measurements are required? */
        uint8_t rc_tlp_cwnd_reduce;     /* Socket option value Lock(a) */
        uint8_t rc_prr_sendalot;/* Socket option value Lock(a) */
        uint8_t rc_rate_sample_method;
};
#endif
 
#define RACK_TIMELY_CNT_BOOST 5 /* At 5th increase boost */
#define RACK_MINRTT_FILTER_TIM 10 /* Seconds */
 
#define RACK_HYSTART_OFF        0
#define RACK_HYSTART_ON         1       /* hystart++ on */
#define RACK_HYSTART_ON_W_SC    2       /* hystart++ on +Slam Cwnd */
#define RACK_HYSTART_ON_W_SC_C  3       /* hystart++ on,
                                         * Conservative ssthresh and
                                         * +Slam cwnd
                                         */
 
#ifdef _KERNEL
 
struct tcp_rack {
        /* First cache line 0x00 */
        TAILQ_ENTRY(tcp_rack) r_hpts;   /* hptsi queue next Lock(b) */
        int32_t(*r_substate) (struct mbuf *, struct tcphdr *,
            struct socket *, struct tcpcb *, struct tcpopt *,
            int32_t, int32_t, uint32_t, int, int, uint8_t);     /* Lock(a) */
        struct tcpcb *rc_tp;    /* The tcpcb Lock(a) */
        struct inpcb *rc_inp;   /* The inpcb Lock(a) */
        uint8_t rc_free_cnt;    /* Number of free entries on the rc_free list
                                 * Lock(a) */
        uint8_t client_bufferlvl;       /* 0 - 5 normaly, less than or at 2 means its real low */
        uint8_t no_prr_addback : 1,
                gp_ready : 1,
                defer_options: 1,
                fast_rsm_hack: 1,
                rc_ack_can_sendout_data: 1, /*
                                             * If set it will override pacing restrictions on not sending
                                             * data when the pacing timer is running. I.e. you set this
                                             * and an ACK will send data. Default is off and its only used
                                             * without pacing when we are doing 5G speed up for there
                                             * ack filtering.
                                             */
                rc_pacing_cc_set: 1,         /*
                                              * If we are pacing (pace_always=1) and we have reached the
                                              * point where we start pacing (fixed or gp has reached its
                                              * magic gp_ready state) this flag indicates we have set in
                                              * values to effect CC's backoff's. If pacing is turned off
                                              * then we must restore the values saved in rc_saved_beta,
                                              * if its going to gp_ready we need to copy the values into
                                              * the CC module and set our flags.
                                              *
                                              * Note this only happens if the cc name is newreno (CCALGONAME_NEWRENO).
                                              */
 
                rc_rack_tmr_std_based :1,
                rc_rack_use_dsack: 1;
        uint8_t rc_dsack_round_seen: 1,
                rc_last_tlp_acked_set: 1,
                rc_last_tlp_past_cumack: 1,
                rc_last_sent_tlp_seq_valid: 1,
                rc_last_sent_tlp_past_cumack: 1,
                probe_not_answered: 1,
                avail_bytes : 2;
        uint32_t rc_rack_rtt;   /* RACK-RTT Lock(a) */
        uint16_t r_mbuf_queue : 1,      /* Do we do mbuf queue for non-paced */
                 rtt_limit_mul : 4,     /* muliply this by low rtt */
                 r_limit_scw : 1,
                 r_must_retran : 1,     /* For non-sack customers we hit an RTO and new data should be resends */
                 r_use_cmp_ack: 1,      /* Do we use compressed acks */
                 r_ent_rec_ns: 1,       /* We entered recovery and have not sent */
                 r_might_revert: 1,     /* Flag to find out if we might need to revert */
                 r_fast_output: 1,      /* Fast output is in progress we can skip the bulk of rack_output */
                 r_fsb_inited: 1,
                 r_rack_hw_rate_caps: 1,
                 r_up_only: 1,
                 r_via_fill_cw : 1,
                 r_fill_less_agg : 1;
 
        uint8_t rc_user_set_max_segs;   /* Socket option value Lock(a) */
        uint8_t rc_labc;                /* Appropriate Byte Counting Value */
        uint16_t forced_ack : 1,
                rc_gp_incr : 1,
                rc_gp_bwred : 1,
                rc_gp_timely_inc_cnt : 3,
                rc_gp_timely_dec_cnt : 3,
                r_use_labc_for_rec: 1,
                rc_highly_buffered: 1,          /* The path is highly buffered */
                rc_dragged_bottom: 1,
                rc_dack_mode : 1,               /* Mac O/S emulation of d-ack */
                rc_dack_toggle : 1,             /* For Mac O/S emulation of d-ack */
                rc_gp_filled : 1,
                rc_is_spare : 1;
        uint8_t r_state;        /* Current rack state Lock(a) */
        uint8_t rc_tmr_stopped : 7,
                t_timers_stopped : 1;
        uint8_t rc_enobuf : 7,  /* count of enobufs on connection provides */
                rc_on_min_to : 1;
        uint8_t r_timer_override : 1,   /* hpts override Lock(a) */
                r_is_v6 : 1,    /* V6 pcb Lock(a)  */
                rc_in_persist : 1,
                rc_tlp_in_progress : 1,
                rc_always_pace : 1,     /* Socket option value Lock(a) */
                rc_pace_to_cwnd : 1,
                rc_pace_fill_if_rttin_range : 1,
                rc_srtt_measure_made : 1;
        uint8_t app_limited_needs_set : 1,
                use_fixed_rate : 1,
                rc_has_collapsed : 1,
                r_rep_attack : 1,
                r_rep_reverse : 1,
                rack_hdrw_pacing : 1,  /* We are doing Hardware pacing */
                rack_hdw_pace_ena : 1, /* Is hardware pacing enabled? */
                rack_attempt_hdwr_pace : 1; /* Did we attempt hdwr pacing (if allowed) */
        uint8_t rack_tlp_threshold_use : 3,     /* only 1, 2 and 3 used so far */
                rack_rec_nonrxt_use_cr : 1,
                rack_enable_scwnd : 1,
                rack_attempted_scwnd : 1,
                rack_no_prr : 1,
                rack_scwnd_is_idle : 1;
        uint8_t rc_allow_data_af_clo: 1,
                delayed_ack : 1,
                set_pacing_done_a_iw : 1,
                use_rack_rr : 1,
                alloc_limit_reported : 1,
                sack_attack_disable : 1,
                do_detection : 1,
                rc_force_max_seg : 1;
        uint8_t r_early : 1,
                r_late : 1,
                r_wanted_output: 1,
                r_rr_config : 2,
                rc_avail_bit : 3;
        uint16_t rc_init_win : 8,
                rc_gp_rtt_set : 1,
                rc_gp_dyn_mul : 1,
                rc_gp_saw_rec : 1,
                rc_gp_saw_ca : 1,
                rc_gp_saw_ss : 1,
                rc_gp_no_rec_chg : 1,
                in_probe_rtt : 1,
                measure_saw_probe_rtt : 1;
        /* Cache line 2 0x40 */
        struct rack_control r_ctl;
}        __aligned(CACHE_LINE_SIZE);
 
#endif
#endif