ssh: Update to OpenSSH 9.7p1

[FreeBSD/FreeBSD.git] / sys / netinet / tcp_var.h

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1993, 1994, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * 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.
 */

#ifndef _NETINET_TCP_VAR_H_
#define _NETINET_TCP_VAR_H_

#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>

#ifdef _KERNEL
#include <net/vnet.h>
#include <sys/mbuf.h>
#include <sys/ktls.h>
#endif

#define TCP_END_BYTE_INFO 8     /* Bytes that makeup the "end information array" */
/* Types of ending byte info */
#define TCP_EI_EMPTY_SLOT       0
#define TCP_EI_STATUS_CLIENT_FIN        0x1
#define TCP_EI_STATUS_CLIENT_RST        0x2
#define TCP_EI_STATUS_SERVER_FIN        0x3
#define TCP_EI_STATUS_SERVER_RST        0x4
#define TCP_EI_STATUS_RETRAN            0x5
#define TCP_EI_STATUS_PROGRESS          0x6
#define TCP_EI_STATUS_PERSIST_MAX       0x7
#define TCP_EI_STATUS_KEEP_MAX          0x8
#define TCP_EI_STATUS_DATA_A_CLOSE      0x9
#define TCP_EI_STATUS_RST_IN_FRONT      0xa
#define TCP_EI_STATUS_2MSL              0xb
#define TCP_EI_STATUS_MAX_VALUE         0xb

#define TCP_TRK_REQ_LOG_NEW             0x01
#define TCP_TRK_REQ_LOG_COMPLETE        0x02
#define TCP_TRK_REQ_LOG_FREED           0x03
#define TCP_TRK_REQ_LOG_ALLOCFAIL       0x04
#define TCP_TRK_REQ_LOG_MOREYET 0x05
#define TCP_TRK_REQ_LOG_FORCEFREE       0x06
#define TCP_TRK_REQ_LOG_STALE           0x07
#define TCP_TRK_REQ_LOG_SEARCH          0x08

/************************************************/
/* Status bits we track to assure no duplicates,
 * the bits here are not used by the code but
 * for human representation. To check a bit we
 * take and shift over by 1 minus the value (1-8).
 */
/************************************************/
#define TCP_EI_BITS_CLIENT_FIN  0x001
#define TCP_EI_BITS_CLIENT_RST  0x002
#define TCP_EI_BITS_SERVER_FIN  0x004
#define TCP_EI_BITS_SERVER_RST  0x008
#define TCP_EI_BITS_RETRAN      0x010
#define TCP_EI_BITS_PROGRESS    0x020
#define TCP_EI_BITS_PRESIST_MAX 0x040
#define TCP_EI_BITS_KEEP_MAX    0x080
#define TCP_EI_BITS_DATA_A_CLO  0x100
#define TCP_EI_BITS_RST_IN_FR   0x200   /* a front state reset */
#define TCP_EI_BITS_2MS_TIMER   0x400   /* 2 MSL timer expired */

#if defined(_KERNEL) || defined(_WANT_TCPCB)
#include <netinet/cc/cc.h>

/* TCP segment queue entry */
struct tseg_qent {
        TAILQ_ENTRY(tseg_qent) tqe_q;
        struct  mbuf   *tqe_m;          /* mbuf contains packet */
        struct  mbuf   *tqe_last;       /* last mbuf in chain */
        tcp_seq tqe_start;              /* TCP Sequence number start */
        int     tqe_len;                /* TCP segment data length */
        uint32_t tqe_flags;             /* The flags from tcp_get_flags() */
        uint32_t tqe_mbuf_cnt;          /* Count of mbuf overhead */
};
TAILQ_HEAD(tsegqe_head, tseg_qent);

struct sackblk {
        tcp_seq start;          /* start seq no. of sack block */
        tcp_seq end;            /* end seq no. */
};

struct sackhole {
        tcp_seq start;          /* start seq no. of hole */
        tcp_seq end;            /* end seq no. */
        tcp_seq rxmit;          /* next seq. no in hole to be retransmitted */
        TAILQ_ENTRY(sackhole) scblink;  /* scoreboard linkage */
};

struct sackhint {
        struct sackhole *nexthole;
        int32_t         sack_bytes_rexmit;
        tcp_seq         last_sack_ack;  /* Most recent/largest sacked ack */

        int32_t         delivered_data; /* Newly acked data from last SACK */

        int32_t         sacked_bytes;   /* Total sacked bytes reported by the
                                         * receiver via sack option
                                         */
        uint32_t        recover_fs;     /* Flight Size at the start of Loss recovery */
        uint32_t        prr_delivered;  /* Total bytes delivered using PRR */
        uint32_t        prr_out;        /* Bytes sent during IN_RECOVERY */
        int32_t         hole_bytes;     /* current number of bytes in scoreboard holes */
        int32_t         lost_bytes;     /* number of rfc6675 IsLost() bytes */
};

#define SEGQ_EMPTY(tp) TAILQ_EMPTY(&(tp)->t_segq)

STAILQ_HEAD(tcp_log_stailq, tcp_log_mem);

#define TCP_TRK_TRACK_FLG_EMPTY 0x00    /* Available */
#define TCP_TRK_TRACK_FLG_USED  0x01    /* In use */
#define TCP_TRK_TRACK_FLG_OPEN  0x02    /* End is not valid (open range request) */
#define TCP_TRK_TRACK_FLG_SEQV  0x04    /* We had a sendfile that touched it  */
#define TCP_TRK_TRACK_FLG_COMP  0x08    /* Sendfile as placed the last bits (range req only) */
#define TCP_TRK_TRACK_FLG_FSND  0x10    /* First send has been done into the seq space */
#define TCP_TRK_TRACK_FLG_LSND  0x20    /* We were able to set the Last Sent */
#define MAX_TCP_TRK_REQ 5               /* Max we will have at once */

struct tcp_sendfile_track {
        uint64_t timestamp;     /* User sent timestamp */
        uint64_t start;         /* Start of sendfile offset */
        uint64_t end;           /* End if not open-range req */
        uint64_t localtime;     /* Time we actually got the req */
        uint64_t deadline;      /* If in CU mode, deadline to delivery */
        uint64_t first_send;    /* Time of first send in the range */
        uint64_t cspr;          /* Client suggested pace rate */
        uint64_t sent_at_fs;    /* What was t_sndbytes as we begun sending */
        uint64_t rxt_at_fs;     /* What was t_snd_rxt_bytes as we begun sending */
        uint64_t sent_at_ls;    /* Sent value at the last send */
        uint64_t rxt_at_ls;     /* Retransmit value at the last send */
        tcp_seq start_seq;      /* First TCP Seq assigned */
        tcp_seq end_seq;        /* If range req last seq */
        uint32_t flags;         /* Type of request open etc */
        uint32_t sbcc_at_s;     /* When we allocate what is the sb_cc */
        uint32_t hint_maxseg;   /* Client hinted maxseg */
        uint32_t playout_ms;    /* Client playout ms */
        uint32_t hybrid_flags;  /* Hybrid flags on this request */
};


/*
 * Change Query responses for a stack switch we create a structure
 * that allows query response from the new stack to the old, if
 * supported.
 *
 * There are three queries currently defined.
 *  - sendmap
 *  - timers
 *  - rack_times
 *
 * For the sendmap query the caller fills in the
 * req and the req_param as the first seq (usually
 * snd_una). When the response comes back indicating
 * that there was data (return value 1), then the caller
 * can build a sendmap entry based on the range and the
 * times. The next query would then be done at the 
 * newly created sendmap_end. Repeated until sendmap_end == snd_max.
 *
 * Flags in sendmap_flags are defined below as well.
 *
 * For timers the standard PACE_TMR_XXXX flags are returned indicating
 * a pacing timer (possibly) and one other timer. If pacing timer then
 * the expiration timeout time in microseconds is in timer_pacing_to.
 * And the value used with whatever timer (if a flag is set) is in
 * timer_rxt. If no timers are running a 0 is returned and of
 * course no flags are set in timer_hpts_flags.
 *
 * The rack_times are a misc collection of information that
 * the old stack might possibly fill in. Of course its possible
 * that an old stack may not have a piece of information. If so
 * then setting that value to zero is advised. Setting any 
 * timestamp passed should only place a zero in it when it
 * is unfilled. This may mean that a time is off by a micro-second
 * but this is ok in the grand scheme of things.
 *
 * When switching stacks it is desireable to get as much information
 * from the old stack to the new stack as possible. Though not always
 * will the stack be compatible in the types of information. The
 * init() function needs to take care when it begins changing 
 * things such as inp_flags2 and the timer units to position these
 * changes at a point where it is unlikely they will fail after
 * making such changes. A stack optionally can have an "undo"
 * function  
 *
 * To transfer information to the old stack from the new in 
 * respect to LRO and the inp_flags2, the new stack should set
 * the inp_flags2 to what it supports. The old stack in its
 * fini() function should call the tcp_handle_orphaned_packets()
 * to clean up any packets. Note that a new stack should attempt
 */

/* Query types */
#define TCP_QUERY_SENDMAP       1
#define TCP_QUERY_TIMERS_UP     2
#define TCP_QUERY_RACK_TIMES    3

/* Flags returned in sendmap_flags */
#define SNDMAP_ACKED            0x000001/* The remote endpoint acked this */
#define SNDMAP_OVERMAX          0x000008/* We have more retran's then we can fit */
#define SNDMAP_SACK_PASSED      0x000010/* A sack was done above this block */
#define SNDMAP_HAS_FIN          0x000040/* segment is sent with fin */
#define SNDMAP_TLP              0x000080/* segment sent as tail-loss-probe */
#define SNDMAP_HAS_SYN          0x000800/* SYN is on this guy */
#define SNDMAP_HAD_PUSH         0x008000/* Push was sent on original send */
#define SNDMAP_MASK  (SNDMAP_ACKED|SNDMAP_OVERMAX|SNDMAP_SACK_PASSED|SNDMAP_HAS_FIN\
                      |SNDMAP_TLP|SNDMAP_HAS_SYN|SNDMAP_HAD_PUSH)
#define SNDMAP_NRTX 3

struct tcp_query_resp {
        int req;
        uint32_t req_param;
        union {
                struct {
                        tcp_seq sendmap_start;
                        tcp_seq sendmap_end;
                        int sendmap_send_cnt;
                        uint64_t sendmap_time[SNDMAP_NRTX];
                        uint64_t sendmap_ack_arrival;
                        int sendmap_flags;
                        uint32_t sendmap_r_rtr_bytes;
                        /* If FAS is available if not 0 */
                        uint32_t sendmap_fas;
                        uint8_t sendmap_dupacks;
                };
                struct {
                        uint32_t timer_hpts_flags;
                        uint32_t timer_pacing_to;
                        uint32_t timer_timer_exp;
                };
                struct {
                        /* Timestamps and rtt's */
                        uint32_t rack_reorder_ts;       /* Last uscts that reordering was seen */
                        uint32_t rack_num_dsacks;       /* Num of dsacks seen */
                        uint32_t rack_rxt_last_time;    /* Last time a RXT/TLP or rack tmr  went off */
                        uint32_t rack_min_rtt;          /* never 0 smallest rtt seen */
                        uint32_t rack_rtt;              /* Last rtt used by rack */
                        uint32_t rack_tmit_time;        /* The time the rtt seg was tmited */
                        uint32_t rack_time_went_idle;   /* If in persist the time we went idle */
                        /* Prr data  */
                        uint32_t rack_sacked;
                        uint32_t rack_holes_rxt;
                        uint32_t rack_prr_delivered;
                        uint32_t rack_prr_recovery_fs;
                        uint32_t rack_prr_out;
                        uint32_t rack_prr_sndcnt;
                        /* TLP data */
                        uint16_t rack_tlp_cnt_out;      /* How many tlp's have been sent */
                        /* Various bits */
                        uint8_t  rack_tlp_out;          /* Is a TLP outstanding */
                        uint8_t  rack_srtt_measured;    /* The previous stack has measured srtt */
                        uint8_t  rack_in_persist;       /* Is the old stack in persists? */
                        uint8_t  rack_wanted_output;    /* Did the prevous stack have a want output set */
                };
        };
};

#define TCP_TMR_GRANULARITY_TICKS       1       /* TCP timers are in ticks (msec if hz=1000)  */
#define TCP_TMR_GRANULARITY_USEC        2       /* TCP timers are in microseconds */

typedef enum {
        TT_REXMT = 0,
        TT_PERSIST,
        TT_KEEP,
        TT_2MSL,
        TT_DELACK,
        TT_N,
} tt_which;

typedef enum {
        TT_PROCESSING = 0,
        TT_PROCESSED,
        TT_STARTING,
        TT_STOPPING,
} tt_what;

/*
 * Tcp control block, one per tcp connection.
 */
struct tcpcb {
        struct inpcb t_inpcb;           /* embedded protocol independent cb */
#define t_start_zero    t_fb
#define t_zero_size     (sizeof(struct tcpcb) - \
                            offsetof(struct tcpcb, t_start_zero))
        struct tcp_function_block *t_fb;/* TCP function call block */
        void    *t_fb_ptr;              /* Pointer to t_fb specific data */

        struct callout t_callout;
        sbintime_t t_timers[TT_N];
        sbintime_t t_precisions[TT_N];

        /* HPTS. Used by BBR and Rack stacks. See tcp_hpts.c for more info. */
        TAILQ_ENTRY(tcpcb)      t_hpts;         /* linkage to HPTS ring */
        STAILQ_HEAD(, mbuf)     t_inqueue;      /* HPTS input packets queue */
        uint32_t t_hpts_request;        /* Current hpts request, zero if
                                         * fits in the pacing window. */
        uint32_t t_hpts_slot;           /* HPTS wheel slot this tcb is. */
        uint32_t t_hpts_drop_reas;      /* Reason we are dropping the pcb. */
        uint32_t t_hpts_gencnt;
        uint16_t t_hpts_cpu;            /* CPU chosen by hpts_cpuid(). */
        uint16_t t_lro_cpu;             /* CPU derived from LRO. */
#define HPTS_CPU_NONE   ((uint16_t)-1)
        enum {
                IHPTS_NONE = 0,
                IHPTS_ONQUEUE,
                IHPTS_MOVING,
        } t_in_hpts;                    /* Is it linked into HPTS? */

        uint32_t t_maxseg:24,           /* maximum segment size */
                _t_logstate:8;          /* State of "black box" logging */
        uint32_t t_port:16,             /* Tunneling (over udp) port */
                t_state:4,              /* state of this connection */
                t_idle_reduce : 1,
                t_delayed_ack: 7,       /* Delayed ack variable */
                t_fin_is_rst: 1,        /* Are fin's treated as resets */
                t_log_state_set: 1,
                bits_spare : 2;
        u_int   t_flags;
        tcp_seq snd_una;                /* sent but unacknowledged */
        tcp_seq snd_max;                /* highest sequence number sent;
                                         * used to recognize retransmits
                                         */
        tcp_seq snd_nxt;                /* send next */
        tcp_seq snd_up;                 /* send urgent pointer */
        uint32_t snd_wnd;               /* send window */
        uint32_t snd_cwnd;              /* congestion-controlled window */
        uint32_t ts_offset;             /* our timestamp offset */
        uint32_t rfbuf_ts;              /* recv buffer autoscaling timestamp */
        int     rcv_numsacks;           /* # distinct sack blks present */
        u_int   t_tsomax;               /* TSO total burst length limit */
        u_int   t_tsomaxsegcount;       /* TSO maximum segment count */
        u_int   t_tsomaxsegsize;        /* TSO maximum segment size in bytes */
        tcp_seq rcv_nxt;                /* receive next */
        tcp_seq rcv_adv;                /* advertised window */
        uint32_t rcv_wnd;               /* receive window */
        u_int   t_flags2;               /* More tcpcb flags storage */
        int     t_srtt;                 /* smoothed round-trip time */
        int     t_rttvar;               /* variance in round-trip time */
        uint32_t ts_recent;             /* timestamp echo data */
        u_char  snd_scale;              /* window scaling for send window */
        u_char  rcv_scale;              /* window scaling for recv window */
        u_char  snd_limited;            /* segments limited transmitted */
        u_char  request_r_scale;        /* pending window scaling */
        tcp_seq last_ack_sent;
        u_int   t_rcvtime;              /* inactivity time */
        tcp_seq rcv_up;                 /* receive urgent pointer */
        int     t_segqlen;              /* segment reassembly queue length */
        uint32_t t_segqmbuflen;         /* total reassembly queue byte length */
        struct  tsegqe_head t_segq;     /* segment reassembly queue */
        uint32_t snd_ssthresh;          /* snd_cwnd size threshold for
                                         * for slow start exponential to
                                         * linear switch
                                         */
        tcp_seq snd_wl1;                /* window update seg seq number */
        tcp_seq snd_wl2;                /* window update seg ack number */

        tcp_seq irs;                    /* initial receive sequence number */
        tcp_seq iss;                    /* initial send sequence number */
        u_int   t_acktime;              /* RACK and BBR incoming new data was acked */
        u_int   t_sndtime;              /* time last data was sent */
        u_int   ts_recent_age;          /* when last updated */
        tcp_seq snd_recover;            /* for use in NewReno Fast Recovery */
        char    t_oobflags;             /* have some */
        char    t_iobc;                 /* input character */
        uint8_t t_nic_ktls_xmit:1,      /* active nic ktls xmit sessions */
                t_nic_ktls_xmit_dis:1,  /* disabled nic xmit ktls? */
                t_nic_ktls_spare:6;     /* spare nic ktls */
        int     t_rxtcur;               /* current retransmit value (ticks) */

        int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
        u_int   t_rtttime;              /* RTT measurement start time */

        tcp_seq t_rtseq;                /* sequence number being timed */
        u_int   t_starttime;            /* time connection was established */
        u_int   t_fbyte_in;             /* ticks time first byte queued in */
        u_int   t_fbyte_out;            /* ticks time first byte queued out */

        u_int   t_pmtud_saved_maxseg;   /* pre-blackhole MSS */
        int     t_blackhole_enter;      /* when to enter blackhole detection */
        int     t_blackhole_exit;       /* when to exit blackhole detection */
        u_int   t_rttmin;               /* minimum rtt allowed */

        int     t_softerror;            /* possible error not yet reported */
        uint32_t max_sndwnd;            /* largest window peer has offered */
        uint32_t snd_cwnd_prev;         /* cwnd prior to retransmit */
        uint32_t snd_ssthresh_prev;     /* ssthresh prior to retransmit */
        tcp_seq snd_recover_prev;       /* snd_recover prior to retransmit */
        int     t_sndzerowin;           /* zero-window updates sent */
        int     snd_numholes;           /* number of holes seen by sender */
        u_int   t_badrxtwin;            /* window for retransmit recovery */
        TAILQ_HEAD(sackhole_head, sackhole) snd_holes;
                                        /* SACK scoreboard (sorted) */
        tcp_seq snd_fack;               /* last seq number(+1) sack'd by rcv'r*/
        struct sackblk sackblks[MAX_SACK_BLKS]; /* seq nos. of sack blocks */
        struct sackhint sackhint;       /* SACK scoreboard hint */
        int     t_rttlow;               /* smallest observerved RTT */
        int     rfbuf_cnt;              /* recv buffer autoscaling byte count */
        struct toedev   *tod;           /* toedev handling this connection */
        int     t_sndrexmitpack;        /* retransmit packets sent */
        int     t_rcvoopack;            /* out-of-order packets received */
        void    *t_toe;                 /* TOE pcb pointer */
        struct cc_algo  *t_cc;          /* congestion control algorithm */
        struct cc_var   t_ccv;          /* congestion control specific vars */
        int     t_bytes_acked;          /* # bytes acked during current RTT */
        u_int   t_maxunacktime;
        u_int   t_keepinit;             /* time to establish connection */
        u_int   t_keepidle;             /* time before keepalive probes begin */
        u_int   t_keepintvl;            /* interval between keepalives */
        u_int   t_keepcnt;              /* number of keepalives before close */
        int     t_dupacks;              /* consecutive dup acks recd */
        int     t_lognum;               /* Number of log entries */
        int     t_loglimit;             /* Maximum number of log entries */
        uint32_t t_rcep;                /* Number of received CE marked pkts */
        uint32_t t_scep;                /* Synced number of delivered CE pkts */
        int64_t t_pacing_rate;          /* bytes / sec, -1 => unlimited */
        struct tcp_log_stailq t_logs;   /* Log buffer */
        struct tcp_log_id_node *t_lin;
        struct tcp_log_id_bucket *t_lib;
        const char *t_output_caller;    /* Function that called tcp_output */
        struct statsblob *t_stats;      /* Per-connection stats */
        /* Should these be a pointer to the arrays or an array? */
        uint32_t t_logsn;               /* Log "serial number" */
        uint32_t gput_ts;               /* Time goodput measurement started */
        tcp_seq gput_seq;               /* Outbound measurement seq */
        tcp_seq gput_ack;               /* Inbound measurement ack */
        int32_t t_stats_gput_prev;      /* XXXLAS: Prev gput measurement */
        uint32_t t_maxpeakrate;         /* max peak rate set by user, bytes/s */
        uint32_t t_sndtlppack;          /* tail loss probe packets sent */
        uint64_t t_sndtlpbyte;          /* total tail loss probe bytes sent */
        uint64_t t_sndbytes;            /* total bytes sent */
        uint64_t t_snd_rxt_bytes;       /* total bytes retransmitted */
        uint32_t t_dsack_bytes;         /* dsack bytes received */
        uint32_t t_dsack_tlp_bytes;     /* dsack bytes received for TLPs sent */
        uint32_t t_dsack_pack;          /* dsack packets we have eceived */
        uint8_t t_tmr_granularity;      /* Granularity of all timers srtt etc */
        uint8_t t_rttupdated;           /* number of times rtt sampled */
        /* TCP Fast Open */
        uint8_t t_tfo_client_cookie_len; /* TFO client cookie length */
        uint32_t t_end_info_status;     /* Status flag of end info */
        unsigned int *t_tfo_pending;    /* TFO server pending counter */
        union {
                uint8_t client[TCP_FASTOPEN_MAX_COOKIE_LEN];
                uint64_t server;
        } t_tfo_cookie;                 /* TCP Fast Open cookie to send */
        union {
                uint8_t t_end_info_bytes[TCP_END_BYTE_INFO];
                uint64_t t_end_info;
        };
        struct osd      t_osd;          /* storage for Khelp module data */
        uint8_t _t_logpoint;    /* Used when a BB log points is enabled */
        /*
         * Keep all #ifdef'ed components at the end of the structure!
         * This is important to minimize problems when compiling modules
         * using this structure from within the modules' directory.
         */
#ifdef TCP_REQUEST_TRK
        /* Response tracking addons. */
        uint8_t t_tcpreq_req;   /* Request count */
        uint8_t t_tcpreq_open;  /* Number of open range requests */
        uint8_t t_tcpreq_closed;        /* Number of closed range requests */
        uint32_t tcp_hybrid_start;      /* Num of times we started hybrid pacing */
        uint32_t tcp_hybrid_stop;       /* Num of times we stopped hybrid pacing */
        uint32_t tcp_hybrid_error;      /* Num of times we failed to start hybrid pacing */
        struct tcp_sendfile_track t_tcpreq_info[MAX_TCP_TRK_REQ];
#endif
#ifdef TCP_ACCOUNTING
        uint64_t tcp_cnt_counters[TCP_NUM_CNT_COUNTERS];
        uint64_t tcp_proc_time[TCP_NUM_CNT_COUNTERS];
#endif
#ifdef TCPPCAP
        struct mbufq t_inpkts;          /* List of saved input packets. */
        struct mbufq t_outpkts;         /* List of saved output packets. */
#endif
};
#endif  /* _KERNEL || _WANT_TCPCB */

#ifdef _KERNEL
struct tcptemp {
        u_char  tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
        struct  tcphdr tt_t;
};

/* SACK scoreboard update status */
typedef enum {
        SACK_NOCHANGE = 0,
        SACK_CHANGE,
        SACK_NEWLOSS
} sackstatus_t;

/* Enable TCP/UDP tunneling port */
#define TCP_TUNNELING_PORT_MIN          0
#define TCP_TUNNELING_PORT_MAX          65535
#define TCP_TUNNELING_PORT_DEFAULT      0

/* Enable TCP/UDP tunneling port */
#define TCP_TUNNELING_OVERHEAD_MIN      sizeof(struct udphdr)
#define TCP_TUNNELING_OVERHEAD_MAX      1024
#define TCP_TUNNELING_OVERHEAD_DEFAULT  TCP_TUNNELING_OVERHEAD_MIN

/* Minimum map entries limit value, if set */
#define TCP_MIN_MAP_ENTRIES_LIMIT       128

/*
 * TODO: We yet need to brave plowing in
 * to tcp_input() and the pru_usrreq() block.
 * Right now these go to the old standards which
 * are somewhat ok, but in the long term may
 * need to be changed. If we do tackle tcp_input()
 * then we need to get rid of the tcp_do_segment()
 * function below.
 */
/* Flags for tcp functions */
#define TCP_FUNC_BEING_REMOVED  0x01    /* Can no longer be referenced */
#define TCP_FUNC_OUTPUT_CANDROP 0x02    /* tfb_tcp_output may ask tcp_drop */

/**
 * Adding a tfb_tcp_handoff_ok function allows the socket
 * option to change stacks to query you even if the
 * connection is in a later stage. You return 0 to
 * say you can take over and run your stack, you return
 * non-zero (an error number) to say no you can't.
 * If the function is undefined you can only change
 * in the early states (before connect or listen).
 *
 * tfb_tcp_fb_init is used to allow the new stack to
 * setup its control block. Among the things it must
 * do is:
 * a) Make sure that the inp_flags2 is setup correctly
 *    for LRO. There are two flags that the previous
 *    stack may have set INP_MBUF_ACKCMP and 
 *    INP_SUPPORTS_MBUFQ. If the new stack does not
 *    support these it *should* clear the flags.
 * b) Make sure that the timers are in the proper
 *    granularity that the stack wants. The stack
 *    should check the t_tmr_granularity field. Currently
 *    there are two values that it may hold 
 *    TCP_TMR_GRANULARITY_TICKS and TCP_TMR_GRANULARITY_USEC.
 *    Use the functions tcp_timer_convert(tp, granularity);
 *    to move the timers to the correct format for your stack.
 *
 * The new stack may also optionally query the tfb_chg_query
 * function if the old stack has one. The new stack may ask
 * for one of three entries and can also state to the old
 * stack its support for the INP_MBUF_ACKCMP and 
 * INP_SUPPORTS_MBUFQ. This is important since if there are
 * queued ack's without that statement the old stack will
 * be forced to discard the queued acks. The requests that
 * can be made for information by the new stacks are:
 *
 * Note also that the tfb_tcp_fb_init() when called can
 * determine if a query is needed by looking at the 
 * value passed in the ptr. The ptr is designed to be
 * set in with any allocated memory, but the address
 * of the condtion (ptr == &tp->t_fb_ptr) will be
 * true if this is not a stack switch but the initial
 * setup of a tcb (which means no query would be needed).
 * If, however, the value is not t_fb_ptr, then the caller
 * is in the middle of a stack switch and is the new stack.
 * A query would be appropriate (if the new stack support 
 * the query mechanism).
 *
 * TCP_QUERY_SENDMAP - Query of outstanding data.
 * TCP_QUERY_TIMERS_UP  - Query about running timers.
 * TCP_SUPPORTED_LRO - Declaration in req_param of 
 *                     the inp_flags2 supported by 
 *                     the new stack.
 * TCP_QUERY_RACK_TIMES - Enquire about various timestamps
 *                        and states the old stack may be in.
 * 
 * tfb_tcp_fb_fini is changed to add a flag to tell
 * the old stack if the tcb is being destroyed or
 * not. A one in the flag means the TCB is being
 * destroyed, a zero indicates its transitioning to
 * another stack (via socket option). The
 * tfb_tcp_fb_fini() function itself should not change timers
 * or inp_flags2 (the tfb_tcp_fb_init() must do that). However
 * if the old stack supports the LRO mbuf queuing, and the new
 * stack does not communicate via chg messages that it too does,
 * it must assume it does not and free any queued mbufs.
 *
 */
struct tcp_function_block {
        char tfb_tcp_block_name[TCP_FUNCTION_NAME_LEN_MAX];
        int     (*tfb_tcp_output)(struct tcpcb *);
        void    (*tfb_tcp_do_segment)(struct tcpcb *, struct mbuf *,
                    struct tcphdr *, int, int, uint8_t);
        int      (*tfb_do_segment_nounlock)(struct tcpcb *, struct mbuf *,
                    struct tcphdr *, int, int, uint8_t, int, struct timeval *);
        int     (*tfb_do_queued_segments)(struct tcpcb *, int);
        int     (*tfb_tcp_ctloutput)(struct tcpcb *, struct sockopt *);
        /* Optional memory allocation/free routine */
        int     (*tfb_tcp_fb_init)(struct tcpcb *, void **);
        void    (*tfb_tcp_fb_fini)(struct tcpcb *, int);
        /* Optional timers, must define all if you define one */
        int     (*tfb_tcp_timer_stop_all)(struct tcpcb *);
        void    (*tfb_tcp_rexmit_tmr)(struct tcpcb *);
        int     (*tfb_tcp_handoff_ok)(struct tcpcb *);
        void    (*tfb_tcp_mtu_chg)(struct tcpcb *tp);
        int     (*tfb_pru_options)(struct tcpcb *, int);
        void    (*tfb_hwtls_change)(struct tcpcb *, int);
        int     (*tfb_chg_query)(struct tcpcb *, struct tcp_query_resp *);
        void    (*tfb_switch_failed)(struct tcpcb *);
        bool    (*tfb_early_wake_check)(struct tcpcb *);
        int     (*tfb_compute_pipe)(struct tcpcb *tp);
        int     (*tfb_stack_info)(struct tcpcb *tp, struct stack_specific_info *);
        void    (*tfb_inherit)(struct tcpcb *tp, struct inpcb *h_inp);
        volatile uint32_t tfb_refcnt;
        uint32_t  tfb_flags;
        uint8_t tfb_id;
};

struct tcp_function {
        TAILQ_ENTRY(tcp_function)       tf_next;
        char                            tf_name[TCP_FUNCTION_NAME_LEN_MAX];
        struct tcp_function_block       *tf_fb;
};

TAILQ_HEAD(tcp_funchead, tcp_function);

struct tcpcb * tcp_drop(struct tcpcb *, int);

#ifdef _NETINET_IN_PCB_H_
#define intotcpcb(inp)  __containerof((inp), struct tcpcb, t_inpcb)
#define sototcpcb(so)   intotcpcb(sotoinpcb(so))
#define tptoinpcb(tp)   (&(tp)->t_inpcb)
#define tptosocket(tp)  (tp)->t_inpcb.inp_socket

/*
 * tcp_output()
 * Handles tcp_drop request from advanced stacks and reports that inpcb is
 * gone with negative return code.
 * Drop in replacement for the default stack.
 */
static inline int
tcp_output(struct tcpcb *tp)
{
        struct inpcb *inp = tptoinpcb(tp);
        int rv;

        INP_WLOCK_ASSERT(inp);

        rv = tp->t_fb->tfb_tcp_output(tp);
        if (rv < 0) {
                KASSERT(tp->t_fb->tfb_flags & TCP_FUNC_OUTPUT_CANDROP,
                    ("TCP stack %s requested tcp_drop(%p)",
                    tp->t_fb->tfb_tcp_block_name, tp));
                tp = tcp_drop(tp, -rv);
                if (tp)
                        INP_WUNLOCK(inp);
        }

        return (rv);
}

/*
 * tcp_output_unlock()
 * Always returns unlocked, handles drop request from advanced stacks.
 * Always returns positive error code.
 */
static inline int
tcp_output_unlock(struct tcpcb *tp)
{
        struct inpcb *inp = tptoinpcb(tp);
        int rv;

        INP_WLOCK_ASSERT(inp);

        rv = tp->t_fb->tfb_tcp_output(tp);
        if (rv < 0) {
                KASSERT(tp->t_fb->tfb_flags & TCP_FUNC_OUTPUT_CANDROP,
                    ("TCP stack %s requested tcp_drop(%p)",
                    tp->t_fb->tfb_tcp_block_name, tp));
                rv = -rv;
                tp = tcp_drop(tp, rv);
                if (tp)
                        INP_WUNLOCK(inp);
        } else
                INP_WUNLOCK(inp);

        return (rv);
}

/*
 * tcp_output_nodrop()
 * Always returns locked.  It is caller's responsibility to run tcp_drop()!
 * Useful in syscall implementations, when we want to perform some logging
 * and/or tracing with tcpcb before calling tcp_drop().  To be used with
 * tcp_unlock_or_drop() later.
 *
 * XXXGL: maybe don't allow stacks to return a drop request at certain
 * TCP states? Why would it do in connect(2)? In recv(2)?
 */
static inline int
tcp_output_nodrop(struct tcpcb *tp)
{
        int rv;

        INP_WLOCK_ASSERT(tptoinpcb(tp));

        rv = tp->t_fb->tfb_tcp_output(tp);
        KASSERT(rv >= 0 || tp->t_fb->tfb_flags & TCP_FUNC_OUTPUT_CANDROP,
            ("TCP stack %s requested tcp_drop(%p)",
            tp->t_fb->tfb_tcp_block_name, tp));
        return (rv);
}

/*
 * tcp_unlock_or_drop()
 * Handle return code from tfb_tcp_output() after we have logged/traced,
 * to be used with tcp_output_nodrop().
 */
static inline int
tcp_unlock_or_drop(struct tcpcb *tp, int tcp_output_retval)
{
        struct inpcb *inp = tptoinpcb(tp);

        INP_WLOCK_ASSERT(inp);

        if (tcp_output_retval < 0) {
                tcp_output_retval = -tcp_output_retval;
                if (tcp_drop(tp, tcp_output_retval) != NULL)
                        INP_WUNLOCK(inp);
        } else
                INP_WUNLOCK(inp);

        return (tcp_output_retval);
}
#endif  /* _NETINET_IN_PCB_H_ */

static int inline
tcp_packets_this_ack(struct tcpcb *tp, tcp_seq ack)
{
        return ((ack - tp->snd_una) / tp->t_maxseg +
                ((((ack - tp->snd_una) % tp->t_maxseg) != 0) ? 1 : 0));
}
#endif  /* _KERNEL */

/*
 * Flags and utility macros for the t_flags field.
 */
#define TF_ACKNOW       0x00000001      /* ack peer immediately */
#define TF_DELACK       0x00000002      /* ack, but try to delay it */
#define TF_NODELAY      0x00000004      /* don't delay packets to coalesce */
#define TF_NOOPT        0x00000008      /* don't use tcp options */
#define TF_SENTFIN      0x00000010      /* have sent FIN */
#define TF_REQ_SCALE    0x00000020      /* have/will request window scaling */
#define TF_RCVD_SCALE   0x00000040      /* other side has requested scaling */
#define TF_REQ_TSTMP    0x00000080      /* have/will request timestamps */
#define TF_RCVD_TSTMP   0x00000100      /* a timestamp was received in SYN */
#define TF_SACK_PERMIT  0x00000200      /* other side said I could SACK */
#define TF_NEEDSYN      0x00000400      /* send SYN (implicit state) */
#define TF_NEEDFIN      0x00000800      /* send FIN (implicit state) */
#define TF_NOPUSH       0x00001000      /* don't push */
#define TF_PREVVALID    0x00002000      /* saved values for bad rxmit valid
                                         * Note: accessing and restoring from
                                         * these may only be done in the 1st
                                         * RTO recovery round (t_rxtshift == 1)
                                         */
#define TF_WAKESOR      0x00004000      /* wake up receive socket */
#define TF_GPUTINPROG   0x00008000      /* Goodput measurement in progress */
#define TF_MORETOCOME   0x00010000      /* More data to be appended to sock */
#define TF_SONOTCONN    0x00020000      /* needs soisconnected() on ESTAB */
#define TF_LASTIDLE     0x00040000      /* connection was previously idle */
#define TF_RXWIN0SENT   0x00080000      /* sent a receiver win 0 in response */
#define TF_FASTRECOVERY 0x00100000      /* in NewReno Fast Recovery */
#define TF_WASFRECOVERY 0x00200000      /* was in NewReno Fast Recovery */
#define TF_SIGNATURE    0x00400000      /* require MD5 digests (RFC2385) */
#define TF_FORCEDATA    0x00800000      /* force out a byte */
#define TF_TSO          0x01000000      /* TSO enabled on this connection */
#define TF_TOE          0x02000000      /* this connection is offloaded */
#define TF_CLOSED       0x04000000      /* close(2) called on socket */
#define TF_SENTSYN      0x08000000      /* At least one syn has been sent */
#define TF_LRD          0x10000000      /* Lost Retransmission Detection */
#define TF_CONGRECOVERY 0x20000000      /* congestion recovery mode */
#define TF_WASCRECOVERY 0x40000000      /* was in congestion recovery */
#define TF_FASTOPEN     0x80000000      /* TCP Fast Open indication */

#define IN_FASTRECOVERY(t_flags)        (t_flags & TF_FASTRECOVERY)
#define ENTER_FASTRECOVERY(t_flags)     t_flags |= TF_FASTRECOVERY
#define EXIT_FASTRECOVERY(t_flags)      t_flags &= ~TF_FASTRECOVERY

#define IN_CONGRECOVERY(t_flags)        (t_flags & TF_CONGRECOVERY)
#define ENTER_CONGRECOVERY(t_flags)     t_flags |= TF_CONGRECOVERY
#define EXIT_CONGRECOVERY(t_flags)      t_flags &= ~TF_CONGRECOVERY

#define IN_RECOVERY(t_flags) (t_flags & (TF_CONGRECOVERY | TF_FASTRECOVERY))
#define ENTER_RECOVERY(t_flags) t_flags |= (TF_CONGRECOVERY | TF_FASTRECOVERY)
#define EXIT_RECOVERY(t_flags) t_flags &= ~(TF_CONGRECOVERY | TF_FASTRECOVERY)

#if defined(_KERNEL)
#if !defined(TCP_RFC7413)
#define IS_FASTOPEN(t_flags)            (false)
#else
#define IS_FASTOPEN(t_flags)            (t_flags & TF_FASTOPEN)
#endif
#endif

#define BYTES_THIS_ACK(tp, th)  (th->th_ack - tp->snd_una)

/*
 * Flags for the t_oobflags field.
 */
#define TCPOOB_HAVEDATA 0x01
#define TCPOOB_HADDATA  0x02

/*
 * Flags for the extended TCP flags field, t_flags2
 */
#define TF2_PLPMTU_BLACKHOLE    0x00000001 /* Possible PLPMTUD Black Hole. */
#define TF2_PLPMTU_PMTUD        0x00000002 /* Allowed to attempt PLPMTUD. */
#define TF2_PLPMTU_MAXSEGSNT    0x00000004 /* Last seg sent was full seg. */
#define TF2_LOG_AUTO            0x00000008 /* Session is auto-logging. */
#define TF2_DROP_AF_DATA        0x00000010 /* Drop after all data ack'd */
#define TF2_ECN_PERMIT          0x00000020 /* connection ECN-ready */
#define TF2_ECN_SND_CWR         0x00000040 /* ECN CWR in queue */
#define TF2_ECN_SND_ECE         0x00000080 /* ECN ECE in queue */
#define TF2_ACE_PERMIT          0x00000100 /* Accurate ECN mode */
#define TF2_HPTS_CPU_SET        0x00000200 /* t_hpts_cpu is not random */
#define TF2_FBYTES_COMPLETE     0x00000400 /* We have first bytes in and out */
#define TF2_ECN_USE_ECT1        0x00000800 /* Use ECT(1) marking on session */
#define TF2_TCP_ACCOUNTING      0x00001000 /* Do TCP accounting */
#define TF2_HPTS_CALLS          0x00002000 /* tcp_output() called via HPTS */
#define TF2_MBUF_L_ACKS         0x00004000 /* large mbufs for ack compression */
#define TF2_MBUF_ACKCMP         0x00008000 /* mbuf ack compression ok */
#define TF2_SUPPORTS_MBUFQ      0x00010000 /* Supports the mbuf queue method */
#define TF2_MBUF_QUEUE_READY    0x00020000 /* Inputs can be queued */
#define TF2_DONT_SACK_QUEUE     0x00040000 /* Don't wake on sack */
#define TF2_CANNOT_DO_ECN       0x00080000 /* The stack does not do ECN */

/*
 * Structure to hold TCP options that are only used during segment
 * processing (in tcp_input), but not held in the tcpcb.
 * It's basically used to reduce the number of parameters
 * to tcp_dooptions and tcp_addoptions.
 * The binary order of the to_flags is relevant for packing of the
 * options in tcp_addoptions.
 */
struct tcpopt {
        u_int32_t       to_flags;       /* which options are present */
#define TOF_MSS         0x0001          /* maximum segment size */
#define TOF_SCALE       0x0002          /* window scaling */
#define TOF_SACKPERM    0x0004          /* SACK permitted */
#define TOF_TS          0x0010          /* timestamp */
#define TOF_SIGNATURE   0x0040          /* TCP-MD5 signature option (RFC2385) */
#define TOF_SACK        0x0080          /* Peer sent SACK option */
#define TOF_FASTOPEN    0x0100          /* TCP Fast Open (TFO) cookie */
#define TOF_MAXOPT      0x0200
        u_int32_t       to_tsval;       /* new timestamp */
        u_int32_t       to_tsecr;       /* reflected timestamp */
        u_char          *to_sacks;      /* pointer to the first SACK blocks */
        u_char          *to_signature;  /* pointer to the TCP-MD5 signature */
        u_int8_t        *to_tfo_cookie; /* pointer to the TFO cookie */
        u_int16_t       to_mss;         /* maximum segment size */
        u_int8_t        to_wscale;      /* window scaling */
        u_int8_t        to_nsacks;      /* number of SACK blocks */
        u_int8_t        to_tfo_len;     /* TFO cookie length */
        u_int32_t       to_spare;       /* UTO */
};

/*
 * Flags for tcp_dooptions.
 */
#define TO_SYN          0x01            /* parse SYN-only options */

struct hc_metrics_lite {        /* must stay in sync with hc_metrics */
        uint32_t        rmx_mtu;        /* MTU for this path */
        uint32_t        rmx_ssthresh;   /* outbound gateway buffer limit */
        uint32_t        rmx_rtt;        /* estimated round trip time */
        uint32_t        rmx_rttvar;     /* estimated rtt variance */
        uint32_t        rmx_cwnd;       /* congestion window */
        uint32_t        rmx_sendpipe;   /* outbound delay-bandwidth product */
        uint32_t        rmx_recvpipe;   /* inbound delay-bandwidth product */
};

#ifndef _NETINET_IN_PCB_H_
struct in_conninfo;
#endif /* _NETINET_IN_PCB_H_ */

/*
 * The smoothed round-trip time and estimated variance
 * are stored as fixed point numbers scaled by the values below.
 * For convenience, these scales are also used in smoothing the average
 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 * With these scales, srtt has 3 bits to the right of the binary point,
 * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 * binary point, and is smoothed with an ALPHA of 0.75.
 */
#define TCP_RTT_SCALE           32      /* multiplier for srtt; 3 bits frac. */
#define TCP_RTT_SHIFT           5       /* shift for srtt; 3 bits frac. */
#define TCP_RTTVAR_SCALE        16      /* multiplier for rttvar; 2 bits */
#define TCP_RTTVAR_SHIFT        4       /* shift for rttvar; 2 bits */
#define TCP_DELTA_SHIFT         2       /* see tcp_input.c */

/*
 * The initial retransmission should happen at rtt + 4 * rttvar.
 * Because of the way we do the smoothing, srtt and rttvar
 * will each average +1/2 tick of bias.  When we compute
 * the retransmit timer, we want 1/2 tick of rounding and
 * 1 extra tick because of +-1/2 tick uncertainty in the
 * firing of the timer.  The bias will give us exactly the
 * 1.5 tick we need.  But, because the bias is
 * statistical, we have to test that we don't drop below
 * the minimum feasible timer (which is 2 ticks).
 * This version of the macro adapted from a paper by Lawrence
 * Brakmo and Larry Peterson which outlines a problem caused
 * by insufficient precision in the original implementation,
 * which results in inappropriately large RTO values for very
 * fast networks.
 */
#define TCP_REXMTVAL(tp) \
        max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
          + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)

/*
 * TCP statistics.
 * Many of these should be kept per connection,
 * but that's inconvenient at the moment.
 */
struct  tcpstat {
        uint64_t tcps_connattempt;      /* connections initiated */
        uint64_t tcps_accepts;          /* connections accepted */
        uint64_t tcps_connects;         /* connections established */
        uint64_t tcps_drops;            /* connections dropped */
        uint64_t tcps_conndrops;        /* embryonic connections dropped */
        uint64_t tcps_minmssdrops;      /* average minmss too low drops */
        uint64_t tcps_closed;           /* conn. closed (includes drops) */
        uint64_t tcps_segstimed;        /* segs where we tried to get rtt */
        uint64_t tcps_rttupdated;       /* times we succeeded */
        uint64_t tcps_delack;           /* delayed acks sent */
        uint64_t tcps_timeoutdrop;      /* conn. dropped in rxmt timeout */
        uint64_t tcps_rexmttimeo;       /* retransmit timeouts */
        uint64_t tcps_persisttimeo;     /* persist timeouts */
        uint64_t tcps_keeptimeo;        /* keepalive timeouts */
        uint64_t tcps_keepprobe;        /* keepalive probes sent */
        uint64_t tcps_keepdrops;        /* connections dropped in keepalive */
        uint64_t tcps_progdrops;        /* drops due to no progress */

        uint64_t tcps_sndtotal;         /* total packets sent */
        uint64_t tcps_sndpack;          /* data packets sent */
        uint64_t tcps_sndbyte;          /* data bytes sent */
        uint64_t tcps_sndrexmitpack;    /* data packets retransmitted */
        uint64_t tcps_sndrexmitbyte;    /* data bytes retransmitted */
        uint64_t tcps_sndrexmitbad;     /* unnecessary packet retransmissions */
        uint64_t tcps_sndacks;          /* ack-only packets sent */
        uint64_t tcps_sndprobe;         /* window probes sent */
        uint64_t tcps_sndurg;           /* packets sent with URG only */
        uint64_t tcps_sndwinup;         /* window update-only packets sent */
        uint64_t tcps_sndctrl;          /* control (SYN|FIN|RST) packets sent */

        uint64_t tcps_rcvtotal;         /* total packets received */
        uint64_t tcps_rcvpack;          /* packets received in sequence */
        uint64_t tcps_rcvbyte;          /* bytes received in sequence */
        uint64_t tcps_rcvbadsum;        /* packets received with ccksum errs */
        uint64_t tcps_rcvbadoff;        /* packets received with bad offset */
        uint64_t tcps_rcvreassfull;     /* packets dropped for no reass space */
        uint64_t tcps_rcvshort;         /* packets received too short */
        uint64_t tcps_rcvduppack;       /* duplicate-only packets received */
        uint64_t tcps_rcvdupbyte;       /* duplicate-only bytes received */
        uint64_t tcps_rcvpartduppack;   /* packets with some duplicate data */
        uint64_t tcps_rcvpartdupbyte;   /* dup. bytes in part-dup. packets */
        uint64_t tcps_rcvoopack;        /* out-of-order packets received */
        uint64_t tcps_rcvoobyte;        /* out-of-order bytes received */
        uint64_t tcps_rcvpackafterwin;  /* packets with data after window */
        uint64_t tcps_rcvbyteafterwin;  /* bytes rcvd after window */
        uint64_t tcps_rcvafterclose;    /* packets rcvd after "close" */
        uint64_t tcps_rcvwinprobe;      /* rcvd window probe packets */
        uint64_t tcps_rcvdupack;        /* rcvd duplicate acks */
        uint64_t tcps_rcvacktoomuch;    /* rcvd acks for unsent data */
        uint64_t tcps_rcvackpack;       /* rcvd ack packets */
        uint64_t tcps_rcvackbyte;       /* bytes acked by rcvd acks */
        uint64_t tcps_rcvwinupd;        /* rcvd window update packets */
        uint64_t tcps_pawsdrop;         /* segments dropped due to PAWS */
        uint64_t tcps_predack;          /* times hdr predict ok for acks */
        uint64_t tcps_preddat;          /* times hdr predict ok for data pkts */
        uint64_t tcps_pcbcachemiss;
        uint64_t tcps_cachedrtt;        /* times cached RTT in route updated */
        uint64_t tcps_cachedrttvar;     /* times cached rttvar updated */
        uint64_t tcps_cachedssthresh;   /* times cached ssthresh updated */
        uint64_t tcps_usedrtt;          /* times RTT initialized from route */
        uint64_t tcps_usedrttvar;       /* times RTTVAR initialized from rt */
        uint64_t tcps_usedssthresh;     /* times ssthresh initialized from rt*/
        uint64_t tcps_persistdrop;      /* timeout in persist state */
        uint64_t tcps_badsyn;           /* bogus SYN, e.g. premature ACK */
        uint64_t tcps_mturesent;        /* resends due to MTU discovery */
        uint64_t tcps_listendrop;       /* listen queue overflows */
        uint64_t tcps_badrst;           /* ignored RSTs in the window */

        uint64_t tcps_sc_added;         /* entry added to syncache */
        uint64_t tcps_sc_retransmitted; /* syncache entry was retransmitted */
        uint64_t tcps_sc_dupsyn;        /* duplicate SYN packet */
        uint64_t tcps_sc_dropped;       /* could not reply to packet */
        uint64_t tcps_sc_completed;     /* successful extraction of entry */
        uint64_t tcps_sc_bucketoverflow;/* syncache per-bucket limit hit */
        uint64_t tcps_sc_cacheoverflow; /* syncache cache limit hit */
        uint64_t tcps_sc_reset;         /* RST removed entry from syncache */
        uint64_t tcps_sc_stale;         /* timed out or listen socket gone */
        uint64_t tcps_sc_aborted;       /* syncache entry aborted */
        uint64_t tcps_sc_badack;        /* removed due to bad ACK */
        uint64_t tcps_sc_unreach;       /* ICMP unreachable received */
        uint64_t tcps_sc_zonefail;      /* zalloc() failed */
        uint64_t tcps_sc_sendcookie;    /* SYN cookie sent */
        uint64_t tcps_sc_recvcookie;    /* SYN cookie received */

        uint64_t tcps_hc_added;         /* entry added to hostcache */
        uint64_t tcps_hc_bucketoverflow;/* hostcache per bucket limit hit */

        uint64_t tcps_finwait2_drops;    /* Drop FIN_WAIT_2 connection after time limit */

        /* SACK related stats */
        uint64_t tcps_sack_recovery_episode; /* SACK recovery episodes */
        uint64_t tcps_sack_rexmits;         /* SACK rexmit segments   */
        uint64_t tcps_sack_rexmit_bytes;    /* SACK rexmit bytes      */
        uint64_t tcps_sack_rcv_blocks;      /* SACK blocks (options) received */
        uint64_t tcps_sack_send_blocks;     /* SACK blocks (options) sent     */
        uint64_t tcps_sack_lostrexmt;       /* SACK lost retransmission recovered */
        uint64_t tcps_sack_sboverflow;      /* times scoreboard overflowed */

        /* ECN related stats */
        uint64_t tcps_ecn_rcvce;                /* ECN Congestion Experienced */
        uint64_t tcps_ecn_rcvect0;              /* ECN Capable Transport */
        uint64_t tcps_ecn_rcvect1;              /* ECN Capable Transport */
        uint64_t tcps_ecn_shs;          /* ECN successful handshakes */
        uint64_t tcps_ecn_rcwnd;        /* # times ECN reduced the cwnd */

        /* TCP_SIGNATURE related stats */
        uint64_t tcps_sig_rcvgoodsig;   /* Total matching signature received */
        uint64_t tcps_sig_rcvbadsig;    /* Total bad signature received */
        uint64_t tcps_sig_err_buildsig; /* Failed to make signature */
        uint64_t tcps_sig_err_sigopt;   /* No signature expected by socket */
        uint64_t tcps_sig_err_nosigopt; /* No signature provided by segment */

        /* Path MTU Discovery Black Hole Detection related stats */
        uint64_t tcps_pmtud_blackhole_activated;         /* Black Hole Count */
        uint64_t tcps_pmtud_blackhole_activated_min_mss; /* BH at min MSS Count */
        uint64_t tcps_pmtud_blackhole_failed;            /* Black Hole Failure Count */

        uint64_t tcps_tunneled_pkts;    /* Packets encap's in UDP received */
        uint64_t tcps_tunneled_errs;    /* Packets that had errors that were UDP encaped */

        /* Dsack related stats */
        uint64_t tcps_dsack_count;      /* Number of ACKs arriving with DSACKs */
        uint64_t tcps_dsack_bytes;      /* Number of bytes DSACK'ed no TLP */
        uint64_t tcps_dsack_tlp_bytes;  /* Number of bytes DSACK'ed due to TLPs */

        /* TCPS_TIME_WAIT usage stats */
        uint64_t tcps_tw_recycles;      /* Times time-wait was recycled. */
        uint64_t tcps_tw_resets;        /* Times time-wait sent a reset. */
        uint64_t tcps_tw_responds;      /* Times time-wait sent a valid ack. */

        /* Accurate ECN Handshake stats */
        uint64_t tcps_ace_nect;         /* ACE SYN packet with Non-ECT */
        uint64_t tcps_ace_ect1;         /* ACE SYN packet with ECT1 */
        uint64_t tcps_ace_ect0;         /* ACE SYN packet with ECT0 */
        uint64_t tcps_ace_ce;           /* ACE SYN packet with CE */

        /* ECN related stats */
        uint64_t tcps_ecn_sndect0;              /* ECN Capable Transport */
        uint64_t tcps_ecn_sndect1;              /* ECN Capable Transport */

        /*
         * BBR and Rack implement TLP's these values count TLP bytes in
         * two catagories, bytes that were retransmitted and bytes that
         * were newly transmited. Both types can serve as TLP's but they
         * are accounted differently.
         */
        uint64_t tcps_tlpresends;       /* number of tlp resends */
        uint64_t tcps_tlpresend_bytes;  /* number of bytes resent by tlp */


        uint64_t _pad[4];               /* 4 TBD placeholder for STABLE */
};

#define tcps_rcvmemdrop tcps_rcvreassfull       /* compat */

#ifdef _KERNEL
#define TI_UNLOCKED     1
#define TI_RLOCKED      2
#include <sys/counter.h>

VNET_PCPUSTAT_DECLARE(struct tcpstat, tcpstat); /* tcp statistics */
/*
 * In-kernel consumers can use these accessor macros directly to update
 * stats.
 */
#define TCPSTAT_ADD(name, val)  \
    VNET_PCPUSTAT_ADD(struct tcpstat, tcpstat, name, (val))
#define TCPSTAT_INC(name)       TCPSTAT_ADD(name, 1)

/*
 * Kernel module consumers must use this accessor macro.
 */
void    kmod_tcpstat_add(int statnum, int val);
#define KMOD_TCPSTAT_ADD(name, val)                                     \
    kmod_tcpstat_add(offsetof(struct tcpstat, name) / sizeof(uint64_t), val)
#define KMOD_TCPSTAT_INC(name)  KMOD_TCPSTAT_ADD(name, 1)

/*
 * Running TCP connection count by state.
 */
VNET_DECLARE(counter_u64_t, tcps_states[TCP_NSTATES]);
#define V_tcps_states   VNET(tcps_states)
#define TCPSTATES_INC(state)    counter_u64_add(V_tcps_states[state], 1)
#define TCPSTATES_DEC(state)    counter_u64_add(V_tcps_states[state], -1)

/*
 * TCP specific helper hook point identifiers.
 */
#define HHOOK_TCP_EST_IN                0
#define HHOOK_TCP_EST_OUT               1
#define HHOOK_TCP_LAST                  HHOOK_TCP_EST_OUT

struct tcp_hhook_data {
        struct tcpcb    *tp;
        struct tcphdr   *th;
        struct tcpopt   *to;
        uint32_t        len;
        int             tso;
        tcp_seq         curack;
};
#ifdef TCP_HHOOK
void hhook_run_tcp_est_out(struct tcpcb *tp,
        struct tcphdr *th, struct tcpopt *to,
        uint32_t len, int tso);
#endif
#endif

/*
 * TCB structure exported to user-land via sysctl(3).
 *
 * Fields prefixed with "xt_" are unique to the export structure, and fields
 * with "t_" or other prefixes match corresponding fields of 'struct tcpcb'.
 *
 * Legend:
 * (s) - used by userland utilities in src
 * (p) - used by utilities in ports
 * (3) - is known to be used by third party software not in ports
 * (n) - no known usage
 *
 * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
 * included.  Not all of our clients do.
 */
#if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
struct xtcpcb {
        ksize_t xt_len;         /* length of this structure */
        struct xinpcb   xt_inp;
        char            xt_stack[TCP_FUNCTION_NAME_LEN_MAX];    /* (s) */
        char            xt_logid[TCP_LOG_ID_LEN];       /* (s) */
        char            xt_cc[TCP_CA_NAME_MAX]; /* (s) */
        int64_t         spare64[6];
        int32_t         t_state;                /* (s,p) */
        uint32_t        t_flags;                /* (s,p) */
        int32_t         t_sndzerowin;           /* (s) */
        int32_t         t_sndrexmitpack;        /* (s) */
        int32_t         t_rcvoopack;            /* (s) */
        int32_t         t_rcvtime;              /* (s) */
        int32_t         tt_rexmt;               /* (s) */
        int32_t         tt_persist;             /* (s) */
        int32_t         tt_keep;                /* (s) */
        int32_t         tt_2msl;                /* (s) */
        int32_t         tt_delack;              /* (s) */
        int32_t         t_logstate;             /* (3) */
        uint32_t        t_snd_cwnd;             /* (s) */
        uint32_t        t_snd_ssthresh;         /* (s) */
        uint32_t        t_maxseg;               /* (s) */
        uint32_t        t_rcv_wnd;              /* (s) */
        uint32_t        t_snd_wnd;              /* (s) */
        uint32_t        xt_ecn;                 /* (s) */
        uint32_t        t_dsack_bytes;          /* (n) */
        uint32_t        t_dsack_tlp_bytes;      /* (n) */
        uint32_t        t_dsack_pack;           /* (n) */
        uint16_t        xt_encaps_port;         /* (s) */
        int16_t         spare16;
        int32_t         spare32[22];
} __aligned(8);

#ifdef _KERNEL
void    tcp_inptoxtp(const struct inpcb *, struct xtcpcb *);
#endif
#endif

/*
 * TCP function information (name-to-id mapping, aliases, and refcnt)
 * exported to user-land via sysctl(3).
 */
struct tcp_function_info {
        uint32_t        tfi_refcnt;
        uint8_t         tfi_id;
        char            tfi_name[TCP_FUNCTION_NAME_LEN_MAX];
        char            tfi_alias[TCP_FUNCTION_NAME_LEN_MAX];
};

/*
 * Identifiers for TCP sysctl nodes
 */
#define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
#define TCPCTL_MSSDFLT          3       /* MSS default */
#define TCPCTL_STATS            4       /* statistics */
#define TCPCTL_RTTDFLT          5       /* default RTT estimate */
#define TCPCTL_KEEPIDLE         6       /* keepalive idle timer */
#define TCPCTL_KEEPINTVL        7       /* interval to send keepalives */
#define TCPCTL_SENDSPACE        8       /* send buffer space */
#define TCPCTL_RECVSPACE        9       /* receive buffer space */
#define TCPCTL_KEEPINIT         10      /* timeout for establishing syn */
#define TCPCTL_PCBLIST          11      /* list of all outstanding PCBs */
#define TCPCTL_DELACKTIME       12      /* time before sending delayed ACK */
#define TCPCTL_V6MSSDFLT        13      /* MSS default for IPv6 */
#define TCPCTL_SACK             14      /* Selective Acknowledgement,rfc 2018 */
#define TCPCTL_DROP             15      /* drop tcp connection */
#define TCPCTL_STATES           16      /* connection counts by TCP state */

#ifdef _KERNEL
#ifdef SYSCTL_DECL
SYSCTL_DECL(_net_inet_tcp);
SYSCTL_DECL(_net_inet_tcp_sack);
MALLOC_DECLARE(M_TCPLOG);
#endif

VNET_DECLARE(int, tcp_log_in_vain);
#define V_tcp_log_in_vain               VNET(tcp_log_in_vain)

/*
 * Global TCP tunables shared between different stacks.
 * Please keep the list sorted.
 */
VNET_DECLARE(int, drop_synfin);
VNET_DECLARE(int, path_mtu_discovery);
VNET_DECLARE(int, tcp_abc_l_var);
VNET_DECLARE(int, tcp_autorcvbuf_max);
VNET_DECLARE(int, tcp_autosndbuf_inc);
VNET_DECLARE(int, tcp_autosndbuf_max);
VNET_DECLARE(int, tcp_delack_enabled);
VNET_DECLARE(int, tcp_do_autorcvbuf);
VNET_DECLARE(int, tcp_do_autosndbuf);
VNET_DECLARE(int, tcp_do_ecn);
VNET_DECLARE(int, tcp_do_lrd);
VNET_DECLARE(int, tcp_do_prr);
VNET_DECLARE(int, tcp_do_prr_conservative);
VNET_DECLARE(int, tcp_do_newcwv);
VNET_DECLARE(int, tcp_do_rfc1323);
VNET_DECLARE(int, tcp_tolerate_missing_ts);
VNET_DECLARE(int, tcp_do_rfc3042);
VNET_DECLARE(int, tcp_do_rfc3390);
VNET_DECLARE(int, tcp_do_rfc3465);
VNET_DECLARE(int, tcp_do_newsack);
VNET_DECLARE(int, tcp_do_sack);
VNET_DECLARE(int, tcp_do_tso);
VNET_DECLARE(int, tcp_ecn_maxretries);
VNET_DECLARE(int, tcp_initcwnd_segments);
VNET_DECLARE(int, tcp_insecure_rst);
VNET_DECLARE(int, tcp_insecure_syn);
VNET_DECLARE(uint32_t, tcp_map_entries_limit);
VNET_DECLARE(uint32_t, tcp_map_split_limit);
VNET_DECLARE(int, tcp_minmss);
VNET_DECLARE(int, tcp_mssdflt);
#ifdef STATS
VNET_DECLARE(int, tcp_perconn_stats_dflt_tpl);
VNET_DECLARE(int, tcp_perconn_stats_enable);
#endif /* STATS */
VNET_DECLARE(int, tcp_recvspace);
VNET_DECLARE(int, tcp_retries);
VNET_DECLARE(int, tcp_sack_globalholes);
VNET_DECLARE(int, tcp_sack_globalmaxholes);
VNET_DECLARE(int, tcp_sack_maxholes);
VNET_DECLARE(int, tcp_sc_rst_sock_fail);
VNET_DECLARE(int, tcp_sendspace);
VNET_DECLARE(int, tcp_udp_tunneling_overhead);
VNET_DECLARE(int, tcp_udp_tunneling_port);
VNET_DECLARE(struct inpcbinfo, tcbinfo);

#define V_tcp_do_lrd                    VNET(tcp_do_lrd)
#define V_tcp_do_prr                    VNET(tcp_do_prr)
#define V_tcp_do_newcwv                 VNET(tcp_do_newcwv)
#define V_drop_synfin                   VNET(drop_synfin)
#define V_path_mtu_discovery            VNET(path_mtu_discovery)
#define V_tcbinfo                       VNET(tcbinfo)
#define V_tcp_abc_l_var                 VNET(tcp_abc_l_var)
#define V_tcp_autorcvbuf_max            VNET(tcp_autorcvbuf_max)
#define V_tcp_autosndbuf_inc            VNET(tcp_autosndbuf_inc)
#define V_tcp_autosndbuf_max            VNET(tcp_autosndbuf_max)
#define V_tcp_delack_enabled            VNET(tcp_delack_enabled)
#define V_tcp_do_autorcvbuf             VNET(tcp_do_autorcvbuf)
#define V_tcp_do_autosndbuf             VNET(tcp_do_autosndbuf)
#define V_tcp_do_ecn                    VNET(tcp_do_ecn)
#define V_tcp_do_rfc1323                VNET(tcp_do_rfc1323)
#define V_tcp_tolerate_missing_ts       VNET(tcp_tolerate_missing_ts)
#define V_tcp_ts_offset_per_conn        VNET(tcp_ts_offset_per_conn)
#define V_tcp_do_rfc3042                VNET(tcp_do_rfc3042)
#define V_tcp_do_rfc3390                VNET(tcp_do_rfc3390)
#define V_tcp_do_rfc3465                VNET(tcp_do_rfc3465)
#define V_tcp_do_newsack                VNET(tcp_do_newsack)
#define V_tcp_do_sack                   VNET(tcp_do_sack)
#define V_tcp_do_tso                    VNET(tcp_do_tso)
#define V_tcp_ecn_maxretries            VNET(tcp_ecn_maxretries)
#define V_tcp_initcwnd_segments         VNET(tcp_initcwnd_segments)
#define V_tcp_insecure_rst              VNET(tcp_insecure_rst)
#define V_tcp_insecure_syn              VNET(tcp_insecure_syn)
#define V_tcp_map_entries_limit         VNET(tcp_map_entries_limit)
#define V_tcp_map_split_limit           VNET(tcp_map_split_limit)
#define V_tcp_minmss                    VNET(tcp_minmss)
#define V_tcp_mssdflt                   VNET(tcp_mssdflt)
#ifdef STATS
#define V_tcp_perconn_stats_dflt_tpl    VNET(tcp_perconn_stats_dflt_tpl)
#define V_tcp_perconn_stats_enable      VNET(tcp_perconn_stats_enable)
#endif /* STATS */
#define V_tcp_recvspace                 VNET(tcp_recvspace)
#define V_tcp_retries                   VNET(tcp_retries)
#define V_tcp_sack_globalholes          VNET(tcp_sack_globalholes)
#define V_tcp_sack_globalmaxholes       VNET(tcp_sack_globalmaxholes)
#define V_tcp_sack_maxholes             VNET(tcp_sack_maxholes)
#define V_tcp_sc_rst_sock_fail          VNET(tcp_sc_rst_sock_fail)
#define V_tcp_sendspace                 VNET(tcp_sendspace)
#define V_tcp_udp_tunneling_overhead    VNET(tcp_udp_tunneling_overhead)
#define V_tcp_udp_tunneling_port        VNET(tcp_udp_tunneling_port)

#ifdef TCP_HHOOK
VNET_DECLARE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST + 1]);
#define V_tcp_hhh               VNET(tcp_hhh)
#endif

void    tcp_account_for_send(struct tcpcb *, uint32_t, uint8_t, uint8_t, bool);
int      tcp_addoptions(struct tcpopt *, u_char *);
struct tcpcb *
         tcp_close(struct tcpcb *);
void     tcp_discardcb(struct tcpcb *);
void     tcp_twstart(struct tcpcb *);
int      tcp_ctloutput(struct socket *, struct sockopt *);
void     tcp_fini(void *);
char    *tcp_log_addrs(struct in_conninfo *, struct tcphdr *, const void *,
            const void *);
char    *tcp_log_vain(struct in_conninfo *, struct tcphdr *, const void *,
            const void *);
int      tcp_reass(struct tcpcb *, struct tcphdr *, tcp_seq *, int *,
            struct mbuf *);
void     tcp_reass_global_init(void);
void     tcp_reass_flush(struct tcpcb *);
void     tcp_dooptions(struct tcpopt *, u_char *, int, int);
void    tcp_dropwithreset(struct mbuf *, struct tcphdr *,
                     struct tcpcb *, int, int);
void    tcp_pulloutofband(struct socket *,
                     struct tcphdr *, struct mbuf *, int);
void    tcp_xmit_timer(struct tcpcb *, int);
void    tcp_newreno_partial_ack(struct tcpcb *, struct tcphdr *);
void    cc_ack_received(struct tcpcb *tp, struct tcphdr *th,
                            uint16_t nsegs, uint16_t type);
void    cc_conn_init(struct tcpcb *tp);
void    cc_post_recovery(struct tcpcb *tp, struct tcphdr *th);
void    cc_ecnpkt_handler(struct tcpcb *tp, struct tcphdr *th, uint8_t iptos);
void    cc_ecnpkt_handler_flags(struct tcpcb *tp, uint16_t flags, uint8_t iptos);
void    cc_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type);
#ifdef TCP_HHOOK
void    hhook_run_tcp_est_in(struct tcpcb *tp,
                            struct tcphdr *th, struct tcpopt *to);
#endif

int      tcp_input(struct mbuf **, int *, int);
int      tcp_autorcvbuf(struct mbuf *, struct tcphdr *, struct socket *,
            struct tcpcb *, int);
int      tcp_input_with_port(struct mbuf **, int *, int, uint16_t);
void    tcp_do_segment(struct tcpcb *, struct mbuf *, struct tcphdr *, int,
    int, uint8_t);

int register_tcp_functions(struct tcp_function_block *blk, int wait);
int register_tcp_functions_as_names(struct tcp_function_block *blk,
    int wait, const char *names[], int *num_names);
int register_tcp_functions_as_name(struct tcp_function_block *blk,
    const char *name, int wait);
int deregister_tcp_functions(struct tcp_function_block *blk, bool quiesce,
    bool force);
struct tcp_function_block *find_and_ref_tcp_functions(struct tcp_function_set *fs);
int find_tcp_function_alias(struct tcp_function_block *blk, struct tcp_function_set *fs);
uint32_t tcp_get_srtt(struct tcpcb *tp, int granularity);
void tcp_switch_back_to_default(struct tcpcb *tp);
struct tcp_function_block *
find_and_ref_tcp_fb(struct tcp_function_block *fs);
int tcp_default_ctloutput(struct tcpcb *tp, struct sockopt *sopt);
int tcp_ctloutput_set(struct inpcb *inp, struct sockopt *sopt);
void tcp_log_socket_option(struct tcpcb *tp, uint32_t option_num,
    uint32_t option_val, int err);


extern counter_u64_t tcp_inp_lro_direct_queue;
extern counter_u64_t tcp_inp_lro_wokeup_queue;
extern counter_u64_t tcp_inp_lro_compressed;
extern counter_u64_t tcp_inp_lro_locks_taken;
extern counter_u64_t tcp_extra_mbuf;
extern counter_u64_t tcp_would_have_but;
extern counter_u64_t tcp_comp_total;
extern counter_u64_t tcp_uncomp_total;
extern counter_u64_t tcp_bad_csums;

#ifdef TCP_SAD_DETECTION
/* Various SACK attack thresholds */
extern int32_t tcp_force_detection;
extern int32_t tcp_sad_limit;
extern int32_t tcp_sack_to_ack_thresh;
extern int32_t tcp_sack_to_move_thresh;
extern int32_t tcp_restoral_thresh;
extern int32_t tcp_sad_decay_val;
extern int32_t tcp_sad_pacing_interval;
extern int32_t tcp_sad_low_pps;
extern int32_t tcp_map_minimum;
extern int32_t tcp_attack_on_turns_on_logging;
#endif
extern uint32_t tcp_ack_war_time_window;
extern uint32_t tcp_ack_war_cnt;

/*
 * Used by tcp_maxmtu() to communicate interface specific features
 * and limits at the time of connection setup.
 */
struct tcp_ifcap {
        int     ifcap;
        u_int   tsomax;
        u_int   tsomaxsegcount;
        u_int   tsomaxsegsize;
};
uint32_t tcp_maxmtu(struct in_conninfo *, struct tcp_ifcap *);
uint32_t tcp_maxmtu6(struct in_conninfo *, struct tcp_ifcap *);

void     tcp6_use_min_mtu(struct tcpcb *);
u_int    tcp_maxseg(const struct tcpcb *);
u_int    tcp_fixed_maxseg(const struct tcpcb *);
void     tcp_mss_update(struct tcpcb *, int, int, struct hc_metrics_lite *,
            struct tcp_ifcap *);
void     tcp_mss(struct tcpcb *, int);
int      tcp_mssopt(struct in_conninfo *);
struct tcpcb *
         tcp_newtcpcb(struct inpcb *);
int      tcp_default_output(struct tcpcb *);
void     tcp_state_change(struct tcpcb *, int);
void     tcp_respond(struct tcpcb *, void *,
            struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, uint16_t);
bool     tcp_twcheck(struct inpcb *, struct tcpopt *, struct tcphdr *,
            struct mbuf *, int);
void     tcp_setpersist(struct tcpcb *);
void     tcp_record_dsack(struct tcpcb *tp, tcp_seq start, tcp_seq end, int tlp);
struct tcptemp *
         tcpip_maketemplate(struct inpcb *);
void     tcpip_fillheaders(struct inpcb *, uint16_t, void *, void *);
void     tcp_timer_activate(struct tcpcb *, tt_which, u_int);
bool     tcp_timer_active(struct tcpcb *, tt_which);
void     tcp_timer_stop(struct tcpcb *);
int      inp_to_cpuid(struct inpcb *inp);
/*
 * All tcp_hc_* functions are IPv4 and IPv6 (via in_conninfo)
 */
void     tcp_hc_init(void);
#ifdef VIMAGE
void     tcp_hc_destroy(void);
#endif
void     tcp_hc_get(struct in_conninfo *, struct hc_metrics_lite *);
uint32_t tcp_hc_getmtu(struct in_conninfo *);
void     tcp_hc_updatemtu(struct in_conninfo *, uint32_t);
void     tcp_hc_update(struct in_conninfo *, struct hc_metrics_lite *);
void     cc_after_idle(struct tcpcb *tp);

extern  struct protosw tcp_protosw;             /* shared for TOE */
extern  struct protosw tcp6_protosw;            /* shared for TOE */

uint32_t tcp_new_ts_offset(struct in_conninfo *);
tcp_seq  tcp_new_isn(struct in_conninfo *);

sackstatus_t
         tcp_sack_doack(struct tcpcb *, struct tcpopt *, tcp_seq);
int      tcp_dsack_block_exists(struct tcpcb *);
void     tcp_update_dsack_list(struct tcpcb *, tcp_seq, tcp_seq);
void     tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_laststart,
            tcp_seq rcv_lastend);
void     tcp_clean_dsack_blocks(struct tcpcb *tp);
void     tcp_clean_sackreport(struct tcpcb *tp);
void     tcp_sack_adjust(struct tcpcb *tp);
struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
void     tcp_do_prr_ack(struct tcpcb *, struct tcphdr *, struct tcpopt *,
            sackstatus_t, u_int *);
void     tcp_lost_retransmission(struct tcpcb *, struct tcphdr *);
void     tcp_sack_partialack(struct tcpcb *, struct tcphdr *, u_int *);
void     tcp_resend_sackholes(struct tcpcb *tp);
void     tcp_free_sackholes(struct tcpcb *tp);
void     tcp_sack_lost_retransmission(struct tcpcb *, struct tcphdr *);
int      tcp_newreno(struct tcpcb *, struct tcphdr *);
int      tcp_compute_pipe(struct tcpcb *);
uint32_t tcp_compute_initwnd(uint32_t);
void     tcp_sndbuf_autoscale(struct tcpcb *, struct socket *, uint32_t);
int      tcp_stats_sample_rollthedice(struct tcpcb *tp, void *seed_bytes,
    size_t seed_len);
int tcp_can_enable_pacing(void);
int tcp_incr_dgp_pacing_cnt(void);
void tcp_dec_dgp_pacing_cnt(void);
void tcp_decrement_paced_conn(void);
void tcp_change_time_units(struct tcpcb *, int);
void tcp_handle_orphaned_packets(struct tcpcb *);

struct mbuf *
         tcp_m_copym(struct mbuf *m, int32_t off0, int32_t *plen,
           int32_t seglimit, int32_t segsize, struct sockbuf *sb, bool hw_tls);

int     tcp_stats_init(void);
void tcp_log_end_status(struct tcpcb *tp, uint8_t status);
#ifdef TCP_REQUEST_TRK
void tcp_req_free_a_slot(struct tcpcb *tp, struct tcp_sendfile_track *ent);
struct tcp_sendfile_track *
tcp_req_find_a_req_that_is_completed_by(struct tcpcb *tp, tcp_seq th_ack, int *ip);
int tcp_req_check_for_comp(struct tcpcb *tp, tcp_seq ack_point);
int
tcp_req_is_entry_comp(struct tcpcb *tp, struct tcp_sendfile_track *ent, tcp_seq ack_point);
struct tcp_sendfile_track *
tcp_req_find_req_for_seq(struct tcpcb *tp, tcp_seq seq);
void
tcp_req_log_req_info(struct tcpcb *tp,
    struct tcp_sendfile_track *req, uint16_t slot,
    uint8_t val, uint64_t offset, uint64_t nbytes);

uint32_t
tcp_estimate_tls_overhead(struct socket *so, uint64_t tls_usr_bytes);
void
tcp_req_alloc_req(struct tcpcb *tp, union tcp_log_userdata *user,
    uint64_t ts);

struct tcp_sendfile_track *
tcp_req_alloc_req_full(struct tcpcb *tp, struct tcp_snd_req *req, uint64_t ts, int rec_dups);


#endif
#ifdef TCP_ACCOUNTING
int tcp_do_ack_accounting(struct tcpcb *tp, struct tcphdr *th, struct tcpopt *to, uint32_t tiwin, int mss);
#endif

static inline void
tcp_lro_features_off(struct tcpcb *tp)
{
        tp->t_flags2 &= ~(TF2_SUPPORTS_MBUFQ|
            TF2_MBUF_QUEUE_READY|
            TF2_DONT_SACK_QUEUE|
            TF2_MBUF_ACKCMP|
            TF2_MBUF_L_ACKS);
}

static inline void
tcp_fields_to_host(struct tcphdr *th)
{

        th->th_seq = ntohl(th->th_seq);
        th->th_ack = ntohl(th->th_ack);
        th->th_win = ntohs(th->th_win);
        th->th_urp = ntohs(th->th_urp);
}

static inline void
tcp_fields_to_net(struct tcphdr *th)
{

        th->th_seq = htonl(th->th_seq);
        th->th_ack = htonl(th->th_ack);
        th->th_win = htons(th->th_win);
        th->th_urp = htons(th->th_urp);
}
#endif /* _KERNEL */

#endif /* _NETINET_TCP_VAR_H_ */