/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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
 */

#ifndef _NETINET_TCP_VAR_H_
#define _NETINET_TCP_VAR_H_
/*
 * Kernel variables for tcp.
 */

/*
 * Tcp control block, one per tcp; fields:
 */
struct tcpcb {
        struct  tcpiphdr *seg_next;     /* sequencing queue */
        struct  tcpiphdr *seg_prev;
        int     t_state;                /* state of this connection */
        int     t_timer[TCPT_NTIMERS];  /* tcp timers */
        int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
        int     t_rxtcur;               /* current retransmit value */
        int     t_dupacks;              /* consecutive dup acks recd */
        u_int   t_maxseg;               /* maximum segment size */
        u_int   t_maxopd;               /* mss plus options */
        int     t_force;                /* 1 if forcing out a byte */
        u_int   t_flags;
#define TF_ACKNOW       0x00001          /* ack peer immediately */
#define TF_DELACK       0x00002          /* ack, but try to delay it */
#define TF_NODELAY      0x00004          /* don't delay packets to coalesce */
#define TF_NOOPT        0x00008          /* don't use tcp options */
#define TF_SENTFIN      0x00010          /* have sent FIN */
#define	TF_REQ_SCALE	0x00020		/* have/will request window scaling */
#define	TF_RCVD_SCALE	0x00040		/* other side has requested scaling */
#define	TF_REQ_TSTMP	0x00080		/* have/will request timestamps */
#define	TF_RCVD_TSTMP	0x00100		/* a timestamp was received in SYN */
#define	TF_SACK_PERMIT	0x00200		/* other side said I could SACK */
#define TF_NEEDSYN	0x00400		/* send SYN (implicit state) */
#define TF_NEEDFIN	0x00800		/* send FIN (implicit state) */
#define TF_NOPUSH	0x01000		/* don't push */
#define	TF_MORETOCOME	0x10000		/* More data to be appended to sock */

        struct  tcpiphdr *t_template;   /* skeletal packet for transmit */
        struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
/*
 * The following fields are used as in the protocol specification.
 * See RFC783, Dec. 1981, page 21.
 */
/* send sequence variables */
        tcp_seq snd_una;                /* send unacknowledged */
        tcp_seq snd_nxt;                /* send next */
        tcp_seq snd_up;                 /* send urgent pointer */
        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 */
        u_long  snd_wnd;                /* send window */
/* receive sequence variables */
        u_long  rcv_wnd;                /* receive window */
        tcp_seq rcv_nxt;                /* receive next */
        tcp_seq rcv_up;                 /* receive urgent pointer */
        tcp_seq irs;                    /* initial receive sequence number */
/*
 * Additional variables for this implementation.
 */
/* receive variables */
        tcp_seq rcv_adv;                /* advertised window */
/* retransmit variables */
        tcp_seq snd_max;                /* highest sequence number sent;
                                         * used to recognize retransmits
                                         */
/* congestion control (for slow start, source quench, retransmit after loss) */
        u_long  snd_cwnd;               /* congestion-controlled window */
        u_long  snd_ssthresh;           /* snd_cwnd size threshold for
                                         * for slow start exponential to
                                         * linear switch
                                         */
/*
 * transmit timing stuff.  See below for scale of srtt and rttvar.
 * "Variance" is actually smoothed difference.
 */
        u_int   t_idle;                 /* inactivity time */
        int     t_rtt;                  /* round trip time */
        tcp_seq t_rtseq;                /* sequence number being timed */
        int     t_srtt;                 /* smoothed round-trip time */
        int     t_rttvar;               /* variance in round-trip time */
	u_int	t_rttmin;		/* minimum rtt allowed */
        u_long  max_sndwnd;             /* largest window peer has offered */

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

/* 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_char	requested_s_scale;
	u_long	ts_recent;		/* timestamp echo data */
	u_long	ts_recent_age;		/* when last updated */
	tcp_seq	last_ack_sent;
	u_long	t_duration;		/* connection duration */

/* More RTT stuff */
	u_long	t_rttupdated;		/* number of times rtt sampled */
};

/*
 * 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_long	to_flag;		/* which options are present */
#define TOF_TS		0x0001		/* timestamp */
	u_long	to_tsval;
	u_long	to_tsecr;
};

#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)

/* XXX
 * We want to avoid doing m_pullup on incoming packets but that
 * means avoiding dtom on the tcp reassembly code.  That in turn means
 * keeping an mbuf pointer in the reassembly queue (since we might
 * have a cluster).  As a quick hack, the source & destination
 * port numbers (which are no longer needed once we've located the
 * tcpcb) are overlayed with an mbuf pointer.
 */
#define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))

/*
 * TCP statistics.
 * Many of these should be kept per connection,
 * but that's inconvenient at the moment.
 */
struct  tcpstat {
        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_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_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_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_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_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 */
};

/*
 * 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 */
#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	/* receive buffer space */
#define	TCPCTL_PCBLIST		11	/* list of all outstanding PCBs */
#define TCPCTL_MAXID		12

#define TCPCTL_NAMES { \
	{ 0, 0 }, \
	{ "rfc1323", CTLTYPE_INT }, \
	{ "mssdflt", CTLTYPE_INT }, \
	{ "stats", CTLTYPE_STRUCT }, \
	{ "rttdflt", CTLTYPE_INT }, \
	{ "keepidle", CTLTYPE_INT }, \
	{ "keepintvl", CTLTYPE_INT }, \
	{ "sendspace", CTLTYPE_INT }, \
	{ "recvspace", CTLTYPE_INT }, \
	{ "keepinit", CTLTYPE_INT }, \
	{ "pcblist", CTLTYPE_STRUCT }, \
}

#ifdef KERNEL
#ifdef SYSCTL_DECL
SYSCTL_DECL(_net_inet_tcp);
#endif

extern	struct inpcbhead tcb;		/* head of queue of active tcpcb's */
extern	struct inpcbinfo tcbinfo;
extern  struct  tcpstat tcpstat; /* tcp statistics */
extern	int tcp_mssdflt;	 /* XXX */
extern	int tcp_minmss;
extern	u_long tcp_now;		 /* for RFC 1323 timestamps */
extern  u_short tcp_lastport;	 /* last assigned port */

void	 tcp_canceltimers(struct tcpcb *);
struct tcpcb *
	 tcp_close(struct tcpcb *);
void	 tcp_ctlinput(int, struct sockaddr *, void *);
int	 tcp_ctloutput(int, struct socket *, int, int, struct mbuf **);
struct tcpcb *
	 tcp_drop(struct tcpcb *, int);
void	 tcp_drain(void);
void	 tcp_fasttimo(void);
void	 tcp_init(void);
void	 tcp_input(struct mbuf *, int);
void	 tcp_mss(struct tcpcb *, int);
int	 tcp_mssopt(struct tcpcb *);
void	 tcp_mtudisc(struct inpcb *, int);
#ifdef __riscos
tcp_seq  tcp_newisn(void);	/* tcp initial send seq # */
#endif
struct tcpcb *
	 tcp_newtcpcb(struct inpcb *);
int	 tcp_output(struct tcpcb *);
void	 tcp_quench(struct inpcb *, int);
void	 tcp_respond(struct tcpcb *,
	    struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
struct rtentry *
	 tcp_rtlookup(struct inpcb *);
void	 tcp_setpersist(struct tcpcb *);
void	 tcp_slowtimo(void);
int	 tcp_sysctl(int *, u_int, void *, size_t *, void *, size_t);
struct tcpiphdr *
	 tcp_template(struct tcpcb *);
struct tcpcb *
	 tcp_timers(struct tcpcb *, int);
void	 tcp_trace(int, int, struct tcpcb *, struct tcpiphdr *, int);
int	 tcp_usrreq(struct socket *,
	    int, struct mbuf *, struct mbuf *, struct mbuf *);

extern	u_long tcp_sendspace;
extern	u_long tcp_recvspace;

#endif /* KERNEL */

#endif /* _NETINET_TCP_VAR_H_ */
