/*
 * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
 * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Jeffrey M. Hsu.
 *
 * 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 DragonFly Project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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.
 */

/*
 * 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.
 *
 *      @(#)tcp_var.h   8.4 (Berkeley) 5/24/95
 * $FreeBSD: src/sys/netinet/tcp_var.h,v 1.56.2.13 2003/02/03 02:34:07 hsu Exp $
 */

#ifndef _NETINET_TCP_VAR_H_
#define _NETINET_TCP_VAR_H_

#ifndef _NETINET_IN_PCB_H_
#include <netinet/in_pcb.h>             /* needed for in_conninfo, inp_gen_t */
#endif
#ifndef _NETINET_TCP_H_
#include <netinet/tcp.h>
#endif

/*
 * Kernel variables for tcp.
 */
extern int tcp_do_rfc1323;
extern int tcp_low_rtobase;
extern int tcp_ncr_linklocal;
extern int tcp_ncr_rxtthresh_max;
extern int tcp_do_sack;
extern int tcp_do_smartsack;
extern int tcp_do_rescuesack;
extern int tcp_aggressive_rescuesack;
extern int tcp_do_rfc6675;
extern int tcp_rfc6675_rxt;
extern int tcp_aggregate_acks;
extern int tcp_eifel_rtoinc;
extern int tcp_prio_synack;

/* TCP segment queue entry */
struct tseg_qent {
        TAILQ_ENTRY(tseg_qent) tqe_q;
        int     tqe_len;                /* TCP segment data length */
        struct  tcphdr *tqe_th;         /* a pointer to tcp header */
        struct  mbuf    *tqe_m;         /* mbuf contains packet */
};
TAILQ_HEAD(tsegqe_head, tseg_qent);
extern int      tcp_reass_maxseg;
extern int      tcp_reass_qsize;
#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_TSEGQ);
#endif

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

#define tcp6cb          tcpcb  /* for KAME src sync over BSD*'s */

struct raw_sackblock {                          /* covers [start, end) */
        tcp_seq rblk_start;
        tcp_seq rblk_end;
};

/* maximum number of SACK blocks that will fit in the TCP option space */
#define MAX_SACK_REPORT_BLOCKS  4

TAILQ_HEAD(sackblock_list, sackblock);

struct scoreboard {
        int nblocks;
        struct sackblock_list sackblocks;
        tcp_seq lostseq;                        /* passed SACK lost test */
        struct sackblock *lastfound;            /* search hint */
        struct sackblock *freecache;            /* one slot free block cache */
};

struct netmsg_tcp_timer;
struct netmsg_base;

struct tcp_pcbport {
        struct inpcbport        t_phd;
} __cachealign;

/*
 * Tcp control block, one per tcp; fields:
 * Organized for 16 byte cacheline efficiency.
 */
struct tcpcb {
        struct  tsegqe_head t_segq;
        int     t_dupacks;              /* consecutive dup acks recd */
        int     t_rxtthresh;            /* # dup acks to start fast rxt */
        int     tt_cpu;                 /* sanity check the cpu */

        struct  tcp_pcbport *t_pcbport; /* per-cpu local port cache for
                                         * accept(2)'ed sockets */

        struct  tcp_callout *tt_rexmt;  /* retransmit timer */
        struct  tcp_callout *tt_persist;/* retransmit persistence */
        struct  tcp_callout *tt_keep;   /* keepalive */
        struct  tcp_callout *tt_2msl;   /* 2*msl TIME_WAIT timer */
        struct  tcp_callout *tt_delack; /* delayed ACK timer */
        struct  netmsg_tcp_timer *tt_msg; /* timer message */

        struct  netmsg_base *tt_sndmore;/* send more segments (fairsend) */

        struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
        int     t_state;                /* state of this connection */
        u_int   t_flags;
#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_PERMITTED 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_LISTEN       0x00002000      /* listen(2) has been called */
#define TF_SIGNATURE    0x00004000      /* require MD5 digests (RFC2385) */
#define TF_NCR          0x00008000      /* Non-Congestion Robustness RFC4653 */
#define TF_MORETOCOME   0x00010000      /* More data to be appended to sock */
#define TF_SAWFIN       0x00020000      /* FIN has been seen */
#define TF_LASTIDLE     0x00040000      /* connection was previously idle */
#define TF_RXWIN0SENT   0x00080000      /* sent a receiver win 0 in response */
#define TF_FASTRECOVERY 0x00100000      /* in Fast Recovery */
#define TF_QUEDFIN      0x00200000      /* FIN has been received */
#define TF_XMITNOW      0x00400000      /* Temporarily override Nagle */
#define TF_UNUSED008    0x00800000
#define TF_UNUSED009    0x01000000
#define TF_FORCE        0x02000000      /* Set if forcing out a byte */
#define TF_ONOUTPUTQ    0x04000000      /* on t_outputq list */
#define TF_FAIRSEND     0x08000000      /* fairsend is requested */
#define TF_UNUSED003    0x10000000
#define TF_UNUSED004    0x20000000
#define TF_KEEPALIVE    0x40000000      /* temporary keepalive */
#define TF_RXRESIZED    0x80000000      /* rcvbuf was resized */
        tcp_seq snd_up;                 /* send urgent pointer */
        u_long  snd_last;               /* time last data were sent */

        tcp_seq snd_una;                /* send unacknowledged */
        tcp_seq snd_recover;            /* for use with Fast Recovery */
        tcp_seq snd_max;                /* highest sequence number sent;
                                         * used to recognize retransmits */
        tcp_seq snd_nxt;                /* send next */

        tcp_seq snd_wl1;                /* window update seg seq number */
        tcp_seq snd_wl2;                /* window update seg ack number */
        tcp_seq iss;                    /* initial send sequence number */
        tcp_seq irs;                    /* initial receive sequence number */

        tcp_seq rcv_nxt;                /* receive next */
        tcp_seq rcv_adv;                /* advertised window */
        u_long  rcv_wnd;                /* receive window */
        tcp_seq rcv_up;                 /* receive urgent pointer */

        u_long  snd_wnd;                /* send window */
        u_long  snd_cwnd;               /* congestion-controlled window */
        u_long  snd_wacked;             /* bytes acked in one send window */
        u_long  snd_ssthresh;           /* snd_cwnd size threshold for
                                         * for slow start exponential to
                                         * linear switch */

        int     t_rxtcur;               /* current retransmit value (ticks) */
        u_int   t_maxseg;               /* maximum segment size */
        int     t_srtt;                 /* smoothed round-trip time */
        int     t_rttvar;               /* variance in round-trip time */

        u_int   t_maxopd;               /* mss plus options */

        u_long  t_rcvtime;              /* reception inactivity time */
        u_long  t_starttime;            /* time connection was established */
        int     t_rtttime;              /* round trip time */
        tcp_seq t_rtseq;                /* sequence number being timed */

        int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
        u_int   t_rttmin;               /* minimum rtt allowed */
        u_int   t_rttbest;              /* best rtt we've seen */
        u_long  t_rttupdated;           /* number of times rtt sampled */
        u_long  max_sndwnd;             /* largest window peer has offered */

        int     t_softerror;            /* possible error not yet reported */
/* out-of-band data */
        char    t_oobflags;             /* have some */
        char    t_iobc;                 /* input character */
#define TCPOOB_HAVEDATA 0x01
#define TCPOOB_HADDATA  0x02

/* RFC 1323 variables */
        u_char  snd_scale;              /* window scaling for send window */
        u_char  rcv_scale;              /* window scaling for recv window */
        u_char  request_r_scale;        /* pending window scaling */
        u_long  ts_recent;              /* timestamp echo data */

        u_long  ts_recent_age;          /* when last updated */
        tcp_seq last_ack_sent;

/* experimental */
        u_int   rxt_flags;
#define TRXT_F_REBASERTO        0x0001  /* Recalculate RTO based on new RTT */
#define TRXT_F_WASFRECOVERY     0x0002  /* was in Fast Recovery */
#define TRXT_F_FIRSTACCACK      0x0004  /* Look for 1st acceptable ACK. */
#define TRXT_F_FASTREXMT        0x0008  /* Did Fast Retransmit. */
#define TRXT_F_EARLYREXMT       0x0010  /* Did Early (Fast) Retransmit. */
        int     t_srtt_prev;            /* adjusted SRTT prior to retransmit */
        int     t_rttvar_prev;          /* RTTVAR prior to retransmit */
        int     t_rxtcur_prev;          /* rexmt timeout prior to retransmit */
        tcp_seq snd_max_prev;           /* SND_MAX prior to retransmit */
        u_long  snd_cwnd_prev;          /* cwnd prior to retransmit */
        u_long  snd_wacked_prev;        /* prior bytes acked in send window */
        u_long  snd_ssthresh_prev;      /* ssthresh prior to retransmit */
        tcp_seq snd_recover_prev;       /* snd_recover prior to retransmit */
        u_long  t_badrxtwin;            /* window for retransmit recovery */
        u_long  t_rexmtTS;              /* timestamp of last retransmit */
        u_char  snd_limited;            /* segments limited transmitted */

        u_int   sack_flags;
#define TSACK_F_SACKRESCUED     0x0001  /* sent rescue SACK recovery data */
#define TSACK_F_DUPSEG          0x0002  /* last seg a duplicate */
#define TSACK_F_ENCLOSESEG      0x0004  /* enclosing SACK block */
#define TSACK_F_SACKLEFT        0x0008  /* send SACK blocks from left side */
        tcp_seq rexmt_high;             /* highest seq # retransmitted + 1 */
        tcp_seq rexmt_rescue;           /* rescue SACKED sequence number */
        tcp_seq snd_max_rexmt;          /* snd_max when rexmting snd_una */
        struct scoreboard scb;          /* sack scoreboard */
        struct raw_sackblock reportblk; /* incoming segment or D-SACK block */
        struct raw_sackblock encloseblk;
        int     nsackhistory;
        struct raw_sackblock sackhistory[MAX_SACK_REPORT_BLOCKS]; /* reported */

        TAILQ_ENTRY(tcpcb) t_outputq;   /* tcp_output needed list */

        /* bandwith limitation */
        u_long  snd_bandwidth;          /* calculated bandwidth or 0 */
        u_long  snd_bwnd;               /* bandwidth-controlled window */
        int     t_bw_rtttime;           /* used for bandwidth calculation */
        tcp_seq t_bw_rtseq;             /* used for bandwidth calculation */

/* anti DoS counters */
        u_long  rcv_second;             /* start of interval second */
        u_long  rcv_pps;                /* received packets per second */
        u_long  rcv_byps;               /* received bytes per second */

        u_int32_t       rfbuf_ts;       /* recv buffer autoscaling timestamp */
        int     rfbuf_cnt;              /* recv buffer autoscaling byte count */

        int     t_keepinit;             /* time to establish connection */

        int     t_keepidle;             /* time before keepalive probes begin */
        int     t_keepintvl;            /* time between keepalive probes */
        int     t_keepcnt;              /* maximum number of keepalive probes */
        int     t_maxidle;              /* time to drop after starting probes */

        int     t_rxtsyn;               /* time spent in SYN or SYN|ACK rexmt */
};

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

#ifdef TCP_SIGNATURE
/*
 * Defines which are needed by the xform_tcp module and tcp_[in|out]put
 * for SADB verification and lookup.
 */
#define TCP_SIGLEN      16      /* length of computed digest in bytes */
#define TCP_KEYLEN_MIN  1       /* minimum length of TCP-MD5 key */
#define TCP_KEYLEN_MAX  80      /* maximum length of TCP-MD5 key */
/*
 * Only a single SA per host may be specified at this time. An SPI is
 * needed in order for the KEY_ALLOCSA() lookup to work.
 */
#define TCP_SIG_SPI     0x1000
#endif /* TCP_SIGNATURE */

/*
 * TCP statistics.
 *
 * NOTE: Make sure this struct's size is multiple cache line size.
 */
struct tcp_stats {
        u_long  tcps_connattempt;       /* connections initiated */
        u_long  tcps_accepts;           /* connections accepted */
        u_long  tcps_connects;          /* connections established */
        u_long  tcps_drops;             /* connections dropped */
        u_long  tcps_conndrops;         /* embryonic connections dropped */
        u_long  tcps_minmssdrops;       /* average minmss too low drops */
        u_long  tcps_closed;            /* conn. closed (includes drops) */
        u_long  tcps_segstimed;         /* segs where we tried to get rtt */
        u_long  tcps_rttupdated;        /* times we succeeded */
        u_long  tcps_delack;            /* delayed acks sent */
        u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
        u_long  tcps_rexmttimeo;        /* retransmit timeouts */
        u_long  tcps_persisttimeo;      /* persist timeouts */
        u_long  tcps_keeptimeo;         /* keepalive timeouts */
        u_long  tcps_keepprobe;         /* keepalive probes sent */
        u_long  tcps_keepdrops;         /* connections dropped in keepalive */

        u_long  tcps_sndtotal;          /* total packets sent */
        u_long  tcps_sndpack;           /* data packets sent */
        u_long  tcps_sndbyte;           /* data bytes sent */
        u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
        u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
        u_long  tcps_sndsackrtopack;    /* packets sent by SACK after RTO */
        u_long  tcps_sndsackrtobyte;    /* bytes sent by SACK after RTO */
        u_long  tcps_sndfastrexmit;     /* Fast Retransmissions */
        u_long  tcps_sndearlyrexmit;    /* early Fast Retransmissions */
        u_long  tcps_sndlimited;        /* Limited Transmit packets */
        u_long  tcps_sndrtobad;         /* spurious RTO retransmissions */
        u_long  tcps_sndfastrexmitbad;  /* spurious Fast Retransmissions */
        u_long  tcps_sndearlyrexmitbad; /* spurious early Fast Retransmissions,
                                           a subset of tcps_sndfastrexmitbad */
        u_long  tcps_eifeldetected;     /* Eifel-detected spurious rexmits */
        u_long  tcps_rttcantdetect;     /* Eifel but not 1/2 RTT-detectable */
        u_long  tcps_rttdetected;       /* RTT-detected spurious RTO rexmits */
        u_long  tcps_sndacks;           /* ack-only packets sent */
        u_long  tcps_sndprobe;          /* window probes sent */
        u_long  tcps_sndurg;            /* packets sent with URG only */
        u_long  tcps_sndwinup;          /* window update-only packets sent */
        u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
        u_long  tcps_sndsackpack;       /* packets sent by SACK recovery alg */
        u_long  tcps_sndsackbyte;       /* bytes sent by SACK recovery */
        u_long  tcps_snduna3;           /* re-retransmit snd_una on 3 new seg */
        u_long  tcps_snduna1;           /* re-retransmit snd_una on 1 new seg */
        u_long  tcps_sndsackopt;        /* SACK options sent */
        u_long  tcps_snddsackopt;       /* D-SACK options sent */
        u_long  tcps_sndidle;           /* sending idle detected */
        u_long  tcps_sackrescue;        /* SACK rescue data packets sent */
        u_long  tcps_sackrescue_try;    /* SACK rescues attempted */
        u_long  tcps_eifelresponse;     /* Eifel responses */

        u_long  tcps_rcvtotal;          /* total packets received */
        u_long  tcps_rcvpack;           /* packets received in sequence */
        u_long  tcps_rcvbyte;           /* bytes received in sequence */
        u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
        u_long  tcps_rcvbadoff;         /* packets received with bad offset */
        u_long  tcps_rcvmemdrop;        /* packets dropped for lack of memory */
        u_long  tcps_rcvshort;          /* packets received too short */
        u_long  tcps_rcvduppack;        /* duplicate-only packets received */
        u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
        u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
        u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
        u_long  tcps_rcvoopack;         /* out-of-order packets received */
        u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
        u_long  tcps_rcvpackafterwin;   /* packets with data after window */
        u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
        u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
        u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
        u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
        u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
        u_long  tcps_rcvackpack;        /* rcvd ack packets */
        u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
        u_long  tcps_rcvwinupd;         /* rcvd window update packets */
        u_long  tcps_pawsdrop;          /* segments dropped due to PAWS */
        u_long  tcps_pawsaccept;        /* segments accepted, PAWS tolerance */
        u_long  tcps_predack;           /* times hdr predict ok for acks */
        u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
        u_long  tcps_pcbcachemiss;
        u_long  tcps_cachedrtt;         /* times cached RTT in route updated */
        u_long  tcps_cachedrttvar;      /* times cached rttvar updated */
        u_long  tcps_cachedssthresh;    /* times cached ssthresh updated */
        u_long  tcps_usedrtt;           /* times RTT initialized from route */
        u_long  tcps_usedrttvar;        /* times RTTVAR initialized from rt */
        u_long  tcps_usedssthresh;      /* times ssthresh initialized from rt*/
        u_long  tcps_persistdrop;       /* timeout in persist state */
        u_long  tcps_badsyn;            /* bogus SYN, e.g. premature ACK */
        u_long  tcps_mturesent;         /* resends due to MTU discovery */
        u_long  tcps_listendrop;        /* listen queue overflows */
        u_long  tcps_rcvbadsackopt;     /* rcvd illegal SACK options */
        u_long  tcps_sackrenege;        /* times other side reneged */

        u_long  tcps_sacksbupdate;      /* times SACK scoreboard updated */
        u_long  tcps_sacksboverflow;    /* times SACK scoreboard overflowed */
        u_long  tcps_sacksbreused;      /* times SACK sb-block reused */
        u_long  tcps_sacksbfailed;      /* times SACK sb update failed */
        u_long  tcps_sacksbfast;        /* times SACK sb-block uses cache */

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

        u_long  tcps_pad[6];            /* pad to cache line size (64B) */
};
#ifdef _KERNEL
CTASSERT((sizeof(struct tcp_stats) & __VM_CACHELINE_MASK) == 0);
#endif

#ifdef _KERNEL

#ifndef _NETINET_TCP_FSM_H_
#include <netinet/tcp_fsm.h>
#endif

struct tcp_state_count {
        u_long  tcps_count[TCP_NSTATES];
} __cachealign;

#define tcpstat tcpstats_percpu[mycpuid]

struct sockopt;

extern struct tcp_stats         tcpstats_percpu[MAXCPU];
extern struct tcp_state_count   tcpstate_count[MAXCPU];

static const int tcprexmtthresh = 3;
#endif

/*
 * 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.
 */
struct tcpopt {
        u_int           to_flags;       /* which options are present */
#define TOF_TS                  0x0001  /* timestamp */
#define TOF_MSS                 0x0010
#define TOF_SCALE               0x0020
#define TOF_SACK_PERMITTED      0x0040
#define TOF_SACK                0x0080
#define TOF_SIGNATURE           0x0100  /* signature option present */
#define TOF_SIGLEN              0x0200  /* signature length valid (RFC2385) */
#define TOF_DSACK               0x0400  /* D-SACK */
#define TOF_SACK_REDUNDANT      0x0800  /* all SACK blocks are known */
        u_int32_t       to_tsval;
        u_int32_t       to_tsecr;
        u_int16_t       to_mss;
        u_int8_t        to_requested_s_scale;
        u_int8_t        to_nsackblocks;
        struct raw_sackblock *to_sackblocks;
};

struct syncache {
        inp_gen_t       sc_inp_gencnt;          /* pointer check */
        struct          tcpcb *sc_tp;           /* tcb for listening socket */
        struct          mbuf *sc_ipopts;        /* source route */
        struct          in_conninfo sc_inc;     /* addresses */
#define sc_route        sc_inc.inc_route
#define sc_route6       sc_inc.inc6_route
        u_int32_t       sc_tsrecent;
        uint16_t        sc_hashval;             /* connection hash */
        uint16_t        sc_pad;                 /* explicit padding */
        tcp_seq         sc_irs;                 /* seq from peer */
        tcp_seq         sc_iss;                 /* our ISS */
        u_long          sc_rxttime;             /* retransmit time */
        u_int16_t       sc_rxtslot;             /* retransmit counter */
        u_int16_t       sc_peer_mss;            /* peer's MSS */
        u_int16_t       sc_wnd;                 /* advertised window */
        u_int8_t        sc_requested_s_scale:4,
                        sc_request_r_scale:4;
        u_int8_t        sc_flags;
#define SCF_NOOPT               0x01            /* no TCP options */
#define SCF_WINSCALE            0x02            /* negotiated window scaling */
#define SCF_TIMESTAMP           0x04            /* negotiated timestamps */
#define SCF_HASH                0x08            /* sc_hashval is valid */
#define SCF_UNREACH             0x10            /* icmp unreachable received */
#define SCF_SACK_PERMITTED      0x20            /* saw SACK permitted option */
#define SCF_SIGNATURE           0x40            /* send MD5 digests */
        int             sc_rxtused;             /* time spent in SYN|ACK rxt */
        u_long          sc_sndwnd;              /* send window */
        TAILQ_ENTRY(syncache) sc_hash;
        TAILQ_ENTRY(syncache) sc_timerq;
};

struct syncache_head {
        TAILQ_HEAD(, syncache)  sch_bucket;
        u_int           sch_length;
};

#define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
#define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))

/*
 * 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)

/*
 * TCB structure exported to user-land via sysctl(3).
 * 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 {
        size_t  xt_len;
        struct  inpcb   xt_inp;
        struct  tcpcb   xt_tp;
        struct  xsocket xt_socket;
        u_quad_t        xt_alignment_hack;
};
#endif

/*
 * Names for TCP sysctl objects
 */
#define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
/* 2 was TCPCTL_DO_RFC1644 */
#define TCPCTL_MSSDFLT          3       /* MSS default */
#define TCPCTL_STATS            4       /* statistics (read-only) */
#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_MAXID            14

#ifdef _KERNEL

#ifdef SYSCTL_DECL
SYSCTL_DECL(_net_inet_tcp);
#endif

#define TCP_DO_SACK(tp)         ((tp)->t_flags & TF_SACK_PERMITTED)
#define TCP_DO_NCR(tp)          (((tp)->t_flags & TF_NCR) && TCP_DO_SACK((tp)))
#define TCP_SACK_BLKEND(len, thflags) \
        ((len) + (((thflags) & TH_FIN) != 0))

struct tcpcbackq {
        TAILQ_HEAD(, tcpcb)     head;
} __cachealign;

extern  struct inpcbinfo tcbinfo[];
extern  struct tcpcbackq tcpcbackq[];

extern  int tcp_mssdflt;        /* XXX */
extern  int tcp_minmss;
extern  int tcp_delack_enabled;
extern  int path_mtu_discovery;

struct ip;
union netmsg;

int      tcp_addrcpu(in_addr_t faddr, in_port_t fport,
            in_addr_t laddr, in_port_t lport);
int      tcp_addrhash(in_addr_t faddr, in_port_t fport,
            in_addr_t laddr, in_port_t lport);
struct lwkt_port *
        tcp_addrport(in_addr_t faddr, in_port_t fport,
            in_addr_t laddr, in_port_t lport);
struct lwkt_port *tcp_addrport0(void);
void     tcp_canceltimers (struct tcpcb *);
struct tcpcb *
         tcp_close (struct tcpcb *);
void     tcp_ctlinput(union netmsg *);
void     tcp_ctloutput(union netmsg *);
struct netmsg_pr_ctloutput *tcp_ctloutmsg(struct sockopt *);
inp_notify_t tcp_get_inpnotify(int cmd, const struct sockaddr *sa,
            int *arg, struct ip **ip0, int *cpuid);
struct tcpcb *
         tcp_drop (struct tcpcb *, int);
void     tcp_drain (void);
void     tcp_init (void);
void     tcp_thread_init (void);
int      tcp_input (struct mbuf **, int *, int);
void     tcp_rmx_init (struct tcpcb *, int);
int      tcp_mssopt (struct tcpcb *);
void     tcp_drop_syn_sent (struct inpcb *, int);
void     tcp_mtudisc (struct inpcb *, int);
void     tcp_newtcpcb (struct inpcb *);
int      tcp_output(struct tcpcb *);
int      tcp_output_fair(struct tcpcb *);
void     tcp_output_init(struct tcpcb *);
void     tcp_output_cancel(struct tcpcb *);
boolean_t
         tcp_output_pending(struct tcpcb *);
void     tcp_quench (struct inpcb *, int);
void     tcp_respond (struct tcpcb *, void *,
            struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
struct rtentry *
         tcp_rtlookup (struct in_conninfo *);
int      tcp_sack_bytes_below(const struct scoreboard *scb, tcp_seq seq);
void     tcp_sack_destroy(struct scoreboard *scb);
void     tcp_sack_discard(struct tcpcb *tp);
void     tcp_sack_report_cleanup(struct tcpcb *tp);
boolean_t
         tcp_sack_report_needed(const struct tcpcb *tp);
int      tcp_sack_ndsack_blocks(const struct raw_sackblock *blocks,
            const int numblocks, tcp_seq snd_una);
void     tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen);
boolean_t
         tcp_sack_has_sacked(const struct scoreboard *scb, u_int amount);
void     tcp_sack_tcpcb_init(struct tcpcb *tp);
uint32_t tcp_sack_compute_pipe(const struct tcpcb *tp);
boolean_t
         tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *len,
                          boolean_t *rescue);
boolean_t
         tcp_sack_islost(const struct scoreboard *scb, tcp_seq seq);
void     tcp_sack_update_lostseq(struct scoreboard *scb, tcp_seq snd_una,
            u_int maxseg, int rxtthresh);
#ifdef later
void     tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una,
                                    u_int maxseg);
void     tcp_sack_save_scoreboard(struct scoreboard *scb);
#endif
void     tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt);
uint32_t tcp_sack_first_unsacked_len(const struct tcpcb *tp);
void     tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to);
void     tcp_save_congestion_state(struct tcpcb *tp);
void     tcp_revert_congestion_state(struct tcpcb *tp);
void     tcp_setpersist (struct tcpcb *);
struct tcptemp *tcp_maketemplate (struct tcpcb *);
void     tcp_freetemplate (struct tcptemp *);
void     tcp_fillheaders (struct tcpcb *, void *, void *, boolean_t);
struct lwkt_port *
         tcp_soport(struct socket *, struct sockaddr *, struct mbuf **);
struct lwkt_port *
         tcp_ctlport(int, struct sockaddr *, void *, int *);
struct lwkt_port *
         tcp_initport(void);
struct tcpcb *
         tcp_timers (struct tcpcb *, int);
void     tcp_trace (short, short, struct tcpcb *, void *, struct tcphdr *,
                        int);
void     tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
u_long   tcp_initial_window(struct tcpcb *tp);
void     tcp_timer_keep_activity(struct tcpcb *tp, int thflags);
void     syncache_init(void);
void     syncache_unreach(struct in_conninfo *, const struct tcphdr *);
int      syncache_expand(struct in_conninfo *, struct tcphdr *,
             struct socket **, struct mbuf *);
int      syncache_add(struct in_conninfo *, struct tcpopt *,
             struct tcphdr *, struct socket *, struct mbuf *);
void     syncache_chkrst(struct in_conninfo *, struct tcphdr *);
void     syncache_badack(struct in_conninfo *);
void     syncache_destroy(struct tcpcb *tp, struct tcpcb *new_tp);

#ifdef TCP_SIGNATURE
int tcpsignature_apply(void *fstate, void *data, unsigned int len);
int tcpsignature_compute(struct mbuf *m, int len, int tcpoptlen,
                u_char *buf, u_int direction);
#endif /* TCP_SIGNATURE */

extern  struct pr_usrreqs tcp_usrreqs;
extern  u_long tcp_sendspace;
extern  u_long tcp_recvspace;
tcp_seq tcp_new_isn (struct tcpcb *);

void    tcp_pcbport_create(struct tcpcb *);
void    tcp_pcbport_destroy(struct tcpcb *);
void    tcp_pcbport_merge_oncpu(struct tcpcb *);

static __inline void
tcp_pcbport_insert(struct tcpcb *ltp, struct inpcb *inp)
{
        struct inpcbport *phd;
        int cpu;

        if (inp->inp_lport != ltp->t_inpcb->inp_lport) {
                /*
                 * This could happen with 'ipfw forward'.
                 */
                in_pcbinsporthash_lport(inp);
                return;
        }

        cpu = mycpuid;
        KASSERT(cpu < netisr_ncpus, ("invalid cpu%d", cpu));
        phd = &ltp->t_pcbport[cpu].t_phd;

        /*
         * NOTE:
         * Set inp_porthash NULL and set inp_phd properly,
         * so that tcp_pcbport_remove() could tell that this
         * inpcb is on the listen tcpcb per-cpu port cache.
         */
        inp->inp_porthash = NULL;
        inp->inp_phd = phd;
        LIST_INSERT_HEAD(&phd->phd_pcblist, inp, inp_portlist);
}

static __inline void
tcp_pcbport_remove(struct inpcb *inp)
{
        if (inp->inp_porthash == NULL && inp->inp_phd != NULL) {
                /*
                 * On listen tcpcb per-cpu port cache.
                 */
                LIST_REMOVE(inp, inp_portlist);
                inp->inp_phd = NULL;
                /* NOTE: Don't whack inp_lport, which may be used later */
        }
}

static __inline void
_TCP_STATE_INC(const struct tcpcb *tp)
{
        tcpstate_count[mycpuid].tcps_count[tp->t_state]++;
}

static __inline void
_TCP_STATE_DEC(const struct tcpcb *tp)
{
        tcpstate_count[mycpuid].tcps_count[tp->t_state]--;
}

static __inline void
_TCP_STATE_SET(struct tcpcb *tp, int state)
{
        tp->t_state = state;
        _TCP_STATE_INC(tp);
}

static __inline void
TCP_STATE_INIT(struct tcpcb *tp)
{
        _TCP_STATE_SET(tp, TCPS_CLOSED);
}

static __inline void
TCP_STATE_TERM(struct tcpcb *tp)
{
        KASSERT(tp->t_state != TCPS_TERMINATING, ("tcpcb was terminated"));
        _TCP_STATE_DEC(tp);
        tp->t_state = TCPS_TERMINATING;
}

static __inline void
TCP_STATE_CHANGE(struct tcpcb *tp, int state)
{
        _TCP_STATE_DEC(tp);
        _TCP_STATE_SET(tp, state);
}

static __inline void
TCP_STATE_MIGRATE_START(const struct tcpcb *tp)
{
        _TCP_STATE_DEC(tp);
}

static __inline void
TCP_STATE_MIGRATE_END(const struct tcpcb *tp)
{
        _TCP_STATE_INC(tp);
}

#endif /* _KERNEL */

#endif /* _NETINET_TCP_VAR_H_ */