/* * 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 *//* * Kernel variables for tcp. *//* * Tcp control block, one per tcp; fields: */struct tcpcb {	struct	tcpiphdr *seg_next;	/* sequencing queue */	struct	tcpiphdr *seg_prev;	short	t_state;		/* state of this connection */	short	t_timer[TCPT_NTIMERS];	/* tcp timers */	short	t_rxtshift;		/* log(2) of rexmt exp. backoff */	short	t_rxtcur;		/* current retransmit value */	short	t_dupacks;		/* consecutive dup acks recd */	u_short	t_maxseg;		/* maximum segment size */	char	t_force;		/* 1 if forcing out a byte */	u_short	t_flags;#define	TF_ACKNOW	0x0001		/* ack peer immediately */#define	TF_DELACK	0x0002		/* ack, but try to delay it */#define	TF_NODELAY	0x0004		/* don't delay packets to coalesce */#define	TF_NOOPT	0x0008		/* don't use tcp options */#define	TF_SENTFIN	0x0010		/* have sent FIN */#define	TF_REQ_SCALE	0x0020		/* have/will request window scaling */#define	TF_RCVD_SCALE	0x0040		/* other side has requested scaling */#define	TF_REQ_TSTMP	0x0080		/* have/will request timestamps */#define	TF_RCVD_TSTMP	0x0100		/* a timestamp was received in SYN */#define	TF_SACK_PERMIT	0x0200		/* other side said I could SACK */	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 */	n_long	snd_wnd;		/* send window *//* receive sequence variables */	n_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) */	n_long	snd_cwnd;		/* congestion-controlled window */	n_long	snd_ssthresh;		/* snd_cwnd size threshhold 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_short	t_idle;			/* inactivity time */	short	t_rtt;			/* round trip time */	tcp_seq	t_rtseq;		/* sequence number being timed */	short	t_srtt;			/* smoothed round-trip time */	short	t_rttvar;		/* variance in round-trip time */	u_short	t_rttmin;		/* minimum rtt allowed */	n_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	short	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;	n_long	ts_recent;		/* timestamp echo data */	n_long	ts_recent_age;		/* when last updated */	tcp_seq	last_ack_sent;/* TUBA stuff */	caddr_t	t_tuba_pcb;		/* next level down pcb for TCP over z */};#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		8	/* multiplier for srtt; 3 bits frac. */#define	TCP_RTT_SHIFT		3	/* shift for srtt; 3 bits frac. */#define	TCP_RTTVAR_SCALE	4	/* multiplier for rttvar; 2 bits */#define	TCP_RTTVAR_SHIFT	2	/* multiplier for rttvar; 2 bits *//* * 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 macro assumes that the value of TCP_RTTVAR_SCALE * is the same as the multiplier for rttvar. */#define	TCP_REXMTVAL(tp) \	(((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)/* 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 {	n_long	tcps_connattempt;	/* connections initiated */	n_long	tcps_accepts;		/* connections accepted */	n_long	tcps_connects;		/* connections established */	n_long	tcps_drops;		/* connections dropped */	n_long	tcps_conndrops;		/* embryonic connections dropped */	n_long	tcps_closed;		/* conn. closed (includes drops) */	n_long	tcps_segstimed;		/* segs where we tried to get rtt */	n_long	tcps_rttupdated;	/* times we succeeded */	n_long	tcps_delack;		/* delayed acks sent */	n_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */	n_long	tcps_rexmttimeo;	/* retransmit timeouts */	n_long	tcps_persisttimeo;	/* persist timeouts */	n_long	tcps_keeptimeo;		/* keepalive timeouts */	n_long	tcps_keepprobe;		/* keepalive probes sent */	n_long	tcps_keepdrops;		/* connections dropped in keepalive */	n_long	tcps_sndtotal;		/* total packets sent */	n_long	tcps_sndpack;		/* data packets sent */	n_long	tcps_sndbyte;		/* data bytes sent */	n_long	tcps_sndrexmitpack;	/* data packets retransmitted */	n_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */	n_long	tcps_sndacks;		/* ack-only packets sent */	n_long	tcps_sndprobe;		/* window probes sent */	n_long	tcps_sndurg;		/* packets sent with URG only */	n_long	tcps_sndwinup;		/* window update-only packets sent */	n_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */	n_long	tcps_rcvtotal;		/* total packets received */	n_long	tcps_rcvpack;		/* packets received in sequence */	n_long	tcps_rcvbyte;		/* bytes received in sequence */	n_long	tcps_rcvbadsum;		/* packets received with ccksum errs */	n_long	tcps_rcvbadoff;		/* packets received with bad offset */	n_long	tcps_rcvshort;		/* packets received too short */	n_long	tcps_rcvduppack;	/* duplicate-only packets received */	n_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */	n_long	tcps_rcvpartduppack;	/* packets with some duplicate data */	n_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */	n_long	tcps_rcvoopack;		/* out-of-order packets received */	n_long	tcps_rcvoobyte;		/* out-of-order bytes received */	n_long	tcps_rcvpackafterwin;	/* packets with data after window */	n_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */	n_long	tcps_rcvafterclose;	/* packets rcvd after "close" */	n_long	tcps_rcvwinprobe;	/* rcvd window probe packets */	n_long	tcps_rcvdupack;		/* rcvd duplicate acks */	n_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */	n_long	tcps_rcvackpack;	/* rcvd ack packets */	n_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */	n_long	tcps_rcvwinupd;		/* rcvd window update packets */	n_long	tcps_pawsdrop;		/* segments dropped due to PAWS */	n_long	tcps_predack;		/* times hdr predict ok for acks */	n_long	tcps_preddat;		/* times hdr predict ok for data pkts */	n_long	tcps_pcbcachemiss;	n_long	tcps_persistdrop;	/* timeout in persist state */	n_long	tcps_badsyn;		/* bogus SYN, e.g. premature ACK */};#ifdef KERNELstruct	inpcb tcb;		/* head of queue of active tcpcb's */struct	tcpstat tcpstat;	/* tcp statistics */n_long	tcp_now;		/* for RFC 1323 timestamps */int	 tcp_attach __P((struct socket *));void	 tcp_canceltimers __P((struct tcpcb *));struct tcpcb *	 tcp_close __P((struct tcpcb *));void	 tcp_ctlinput __P((int, struct sockaddr *, struct ip *));int	 tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **));struct tcpcb *	 tcp_disconnect __P((struct tcpcb *));struct tcpcb *	 tcp_drop __P((struct tcpcb *, int));void	 tcp_dooptions __P((struct tcpcb *,	    u_char *, int, struct tcpiphdr *, int *, n_long *, n_long *));void	 tcp_drain __P((void));void	 tcp_fasttimo __P((void));void	 tcp_init __P((void));void	 tcp_input __P((struct mbuf *, int));int	 tcp_mss __P((struct tcpcb *, u_int));struct tcpcb *	 tcp_newtcpcb __P((struct inpcb *));void	 tcp_notify __P((struct inpcb *, int));int	 tcp_output __P((struct tcpcb *));void	 tcp_pulloutofband __P((struct socket *,	    struct tcpiphdr *, struct mbuf *));void	 tcp_quench __P((struct inpcb *, int));int	 tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *));void	 tcp_respond __P((struct tcpcb *,	    struct tcpiphdr *, struct mbuf *, n_long, n_long, int));void	 tcp_setpersist __P((struct tcpcb *));void	 tcp_slowtimo __P((void));struct tcpiphdr *	 tcp_template __P((struct tcpcb *));struct tcpcb *	 tcp_timers __P((struct tcpcb *, int));void	 tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int));struct tcpcb *	 tcp_usrclosed __P((struct tcpcb *));int	 tcp_usrreq __P((struct socket *,	    int, struct mbuf *, struct mbuf *, struct mbuf *));void	 tcp_xmit_timer __P((struct tcpcb *, int));#endif