File:  [DragonFly] / src / sys / netinet / tcp_var.h
Revision 1.16: download - view: text, annotated - select for diffs
Wed Apr 7 17:01:25 2004 UTC (10 years, 3 months ago) by dillon
Branches: MAIN
CVS tags: HEAD
Make TCP stats per-cpu.

Submitted-by: Hiten Pandya <hmp@crater.dragonflybsd.org>

    1: /*
    2:  * Copyright (c) 2003-2004 Jeffrey Hsu.  All rights reserved.
    3:  * Copyright (c) 1982, 1986, 1993, 1994, 1995
    4:  *	The Regents of the University of California.  All rights reserved.
    5:  *
    6:  * Redistribution and use in source and binary forms, with or without
    7:  * modification, are permitted provided that the following conditions
    8:  * are met:
    9:  * 1. Redistributions of source code must retain the above copyright
   10:  *    notice, this list of conditions and the following disclaimer.
   11:  * 2. Redistributions in binary form must reproduce the above copyright
   12:  *    notice, this list of conditions and the following disclaimer in the
   13:  *    documentation and/or other materials provided with the distribution.
   14:  * 3. All advertising materials mentioning features or use of this software
   15:  *    must display the following acknowledgement:
   16:  *	This product includes software developed by the University of
   17:  *	California, Berkeley and its contributors.
   18:  * 4. Neither the name of the University nor the names of its contributors
   19:  *    may be used to endorse or promote products derived from this software
   20:  *    without specific prior written permission.
   21:  *
   22:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32:  * SUCH DAMAGE.
   33:  *
   34:  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
   35:  * $FreeBSD: src/sys/netinet/tcp_var.h,v 1.56.2.13 2003/02/03 02:34:07 hsu Exp $
   36:  * $DragonFly: src/sys/netinet/tcp_var.h,v 1.16 2004/04/07 17:01:25 dillon Exp $
   37:  */
   38: 
   39: #ifndef _NETINET_TCP_VAR_H_
   40: #define _NETINET_TCP_VAR_H_
   41: 
   42: #include <netinet/in_pcb.h>		/* needed for in_conninfo, inp_gen_t */
   43: 
   44: #ifndef _NETINET_TCP_STATS_H_
   45: #include <netinet/tcp_stats.h>
   46: #endif
   47: 
   48: /*
   49:  * Kernel variables for tcp.
   50:  */
   51: extern int	tcp_do_rfc1323;
   52: extern int	tcp_do_rfc1644;
   53: 
   54: /* TCP segment queue entry */
   55: struct tseg_qent {
   56: 	LIST_ENTRY(tseg_qent) tqe_q;
   57: 	int	tqe_len;		/* TCP segment data length */
   58: 	struct	tcphdr *tqe_th;		/* a pointer to tcp header */
   59: 	struct	mbuf	*tqe_m;		/* mbuf contains packet */
   60: };
   61: LIST_HEAD(tsegqe_head, tseg_qent);
   62: extern int	tcp_reass_maxseg;
   63: extern int	tcp_reass_qsize;
   64: #ifdef MALLOC_DECLARE
   65: MALLOC_DECLARE(M_TSEGQ);
   66: #endif
   67: 
   68: struct tcptemp {
   69: 	u_char	tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
   70: 	struct	tcphdr tt_t;
   71: };
   72: 
   73: #define tcp6cb		tcpcb  /* for KAME src sync over BSD*'s */
   74: 
   75: /*
   76:  * Tcp control block, one per tcp; fields:
   77:  * Organized for 16 byte cacheline efficiency.
   78:  */
   79: struct tcpcb {
   80: 	struct	tsegqe_head t_segq;
   81: 	int	t_dupacks;		/* consecutive dup acks recd */
   82: 	struct	tcptemp	*unused;	/* unused */
   83: 
   84: 	struct	callout *tt_rexmt;	/* retransmit timer */
   85: 	struct	callout *tt_persist;	/* retransmit persistence */
   86: 	struct	callout *tt_keep;	/* keepalive */
   87: 	struct	callout *tt_2msl;	/* 2*msl TIME_WAIT timer */
   88: 	struct	callout *tt_delack;	/* delayed ACK timer */
   89: 
   90: 	struct	inpcb *t_inpcb;		/* back pointer to internet pcb */
   91: 	int	t_state;		/* state of this connection */
   92: 	u_int	t_flags;
   93: #define	TF_ACKNOW	0x00000001	/* ack peer immediately */
   94: #define	TF_DELACK	0x00000002	/* ack, but try to delay it */
   95: #define	TF_NODELAY	0x00000004	/* don't delay packets to coalesce */
   96: #define	TF_NOOPT	0x00000008	/* don't use tcp options */
   97: #define	TF_SENTFIN	0x00000010	/* have sent FIN */
   98: #define	TF_REQ_SCALE	0x00000020	/* have/will request window scaling */
   99: #define	TF_RCVD_SCALE	0x00000040	/* other side has requested scaling */
  100: #define	TF_REQ_TSTMP	0x00000080	/* have/will request timestamps */
  101: #define	TF_RCVD_TSTMP	0x00000100	/* a timestamp was received in SYN */
  102: #define	TF_SACK_PERMIT	0x00000200	/* other side said I could SACK */
  103: #define	TF_NEEDSYN	0x00000400	/* send SYN (implicit state) */
  104: #define	TF_NEEDFIN	0x00000800	/* send FIN (implicit state) */
  105: #define	TF_NOPUSH	0x00001000	/* don't push */
  106: #define	TF_REQ_CC	0x00002000	/* have/will request CC */
  107: #define	TF_RCVD_CC	0x00004000	/* a CC was received in SYN */
  108: #define	TF_SENDCCNEW	0x00008000	/* send CCnew instead of CC in SYN */
  109: #define	TF_MORETOCOME	0x00010000	/* More data to be appended to sock */
  110: #define	TF_LQ_OVERFLOW	0x00020000	/* listen queue overflow */
  111: #define	TF_LASTIDLE	0x00040000	/* connection was previously idle */
  112: #define	TF_RXWIN0SENT	0x00080000	/* sent a receiver win 0 in response */
  113: #define	TF_FASTRECOVERY	0x00100000	/* in NewReno Fast Recovery */
  114: #define	TF_WASFRECOVERY	0x00200000	/* was in NewReno Fast Recovery */
  115: #define	TF_FIRSTACCACK	0x00400000	/* Look for 1st acceptable ACK. */
  116: #define	TF_FASTREXMT	0x00800000	/* Did Fast Retransmit. */
  117: #define	TF_EARLYREXMT	0x01000000	/* Did Early (Fast) Retransmit. */
  118: 	int	t_force;		/* 1 if forcing out a byte */
  119: 
  120: 	tcp_seq	snd_una;		/* send unacknowledged */
  121: 	tcp_seq	snd_max;		/* highest sequence number sent;
  122: 					 * used to recognize retransmits
  123: 					 */
  124: 	tcp_seq	snd_nxt;		/* send next */
  125: 	tcp_seq	snd_up;			/* send urgent pointer */
  126: 
  127: 	tcp_seq	snd_wl1;		/* window update seg seq number */
  128: 	tcp_seq	snd_wl2;		/* window update seg ack number */
  129: 	tcp_seq	iss;			/* initial send sequence number */
  130: 	tcp_seq	irs;			/* initial receive sequence number */
  131: 
  132: 	tcp_seq	rcv_nxt;		/* receive next */
  133: 	tcp_seq	rcv_adv;		/* advertised window */
  134: 	u_long	rcv_wnd;		/* receive window */
  135: 	tcp_seq	rcv_up;			/* receive urgent pointer */
  136: 
  137: 	u_long	snd_wnd;		/* send window */
  138: 	u_long	snd_cwnd;		/* congestion-controlled window */
  139: 	u_long	snd_bwnd;		/* bandwidth-controlled window */
  140: 	u_long	snd_ssthresh;		/* snd_cwnd size threshold for
  141: 					 * for slow start exponential to
  142: 					 * linear switch
  143: 					 */
  144: 	u_long	snd_bandwidth;		/* calculated bandwidth or 0 */
  145: 	tcp_seq	snd_recover;		/* for use in NewReno fast recovery */
  146: 
  147: 	u_int	t_maxopd;		/* mss plus options */
  148: 
  149: 	u_long	t_rcvtime;		/* inactivity time */
  150: 	u_long	t_starttime;		/* time connection was established */
  151: 	int	t_rtttime;		/* round trip time */
  152: 	tcp_seq	t_rtseq;		/* sequence number being timed */
  153: 
  154: 	int	t_bw_rtttime;		/* used for bandwidth calculation */
  155: 	tcp_seq	t_bw_rtseq;		/* used for bandwidth calculation */
  156: 
  157: 	int	t_rxtcur;		/* current retransmit value (ticks) */
  158: 	u_int	t_maxseg;		/* maximum segment size */
  159: 	int	t_srtt;			/* smoothed round-trip time */
  160: 	int	t_rttvar;		/* variance in round-trip time */
  161: 
  162: 	int	t_rxtshift;		/* log(2) of rexmt exp. backoff */
  163: 	u_int	t_rttmin;		/* minimum rtt allowed */
  164: 	u_int	t_rttbest;		/* best rtt we've seen */
  165: 	u_long	t_rttupdated;		/* number of times rtt sampled */
  166: 	u_long	max_sndwnd;		/* largest window peer has offered */
  167: 
  168: 	int	t_softerror;		/* possible error not yet reported */
  169: /* out-of-band data */
  170: 	char	t_oobflags;		/* have some */
  171: 	char	t_iobc;			/* input character */
  172: #define	TCPOOB_HAVEDATA	0x01
  173: #define	TCPOOB_HADDATA	0x02
  174: /* RFC 1323 variables */
  175: 	u_char	snd_scale;		/* window scaling for send window */
  176: 	u_char	rcv_scale;		/* window scaling for recv window */
  177: 	u_char	request_r_scale;	/* pending window scaling */
  178: 	u_char	requested_s_scale;
  179: 	u_long	ts_recent;		/* timestamp echo data */
  180: 
  181: 	u_long	ts_recent_age;		/* when last updated */
  182: 	tcp_seq	last_ack_sent;
  183: /* RFC 1644 variables */
  184: 	tcp_cc	cc_send;		/* send connection count */
  185: 	tcp_cc	cc_recv;		/* receive connection count */
  186: /* experimental */
  187: 	u_long	snd_cwnd_prev;		/* cwnd prior to retransmit */
  188: 	u_long	snd_ssthresh_prev;	/* ssthresh prior to retransmit */
  189: 	tcp_seq snd_recover_prev;	/* snd_recover prior to retransmit */
  190: 	u_long	t_badrxtwin;		/* window for retransmit recovery */
  191: 	u_long	t_rexmtTS;		/* timestamp of last retransmit */
  192: 	u_char	snd_limited;		/* segments limited transmitted */
  193: };
  194: 
  195: #define	IN_FASTRECOVERY(tp)	(tp->t_flags & TF_FASTRECOVERY)
  196: #define	ENTER_FASTRECOVERY(tp)	tp->t_flags |= TF_FASTRECOVERY
  197: #define	EXIT_FASTRECOVERY(tp)	tp->t_flags &= ~TF_FASTRECOVERY
  198: 
  199: /*
  200:  * Structure to hold TCP options that are only used during segment
  201:  * processing (in tcp_input), but not held in the tcpcb.
  202:  * It's basically used to reduce the number of parameters
  203:  * to tcp_dooptions.
  204:  */
  205: struct tcpopt {
  206: 	u_long		to_flags;	/* which options are present */
  207: #define TOF_TS		0x0001		/* timestamp */
  208: #define TOF_CC		0x0002		/* CC and CCnew are exclusive */
  209: #define TOF_CCNEW	0x0004
  210: #define	TOF_CCECHO	0x0008
  211: #define	TOF_MSS		0x0010
  212: #define	TOF_SCALE	0x0020
  213: 	u_int32_t	to_tsval;
  214: 	u_int32_t	to_tsecr;
  215: 	tcp_cc		to_cc;		/* holds CC or CCnew */
  216: 	tcp_cc		to_ccecho;
  217: 	u_int16_t	to_mss;
  218: 	u_int8_t 	to_requested_s_scale;
  219: 	u_int8_t 	to_pad;
  220: };
  221: 
  222: struct syncache {
  223: 	inp_gen_t	sc_inp_gencnt;		/* pointer check */
  224: 	struct 		tcpcb *sc_tp;		/* tcb for listening socket */
  225: 	struct		mbuf *sc_ipopts;	/* source route */
  226: 	struct 		in_conninfo sc_inc;	/* addresses */
  227: #define sc_route	sc_inc.inc_route
  228: #define sc_route6	sc_inc.inc6_route
  229: 	u_int32_t	sc_tsrecent;
  230: 	tcp_cc		sc_cc_send;		/* holds CC or CCnew */
  231: 	tcp_cc		sc_cc_recv;
  232: 	tcp_seq 	sc_irs;			/* seq from peer */
  233: 	tcp_seq 	sc_iss;			/* our ISS */
  234: 	u_long		sc_rxttime;		/* retransmit time */
  235: 	u_int16_t	sc_rxtslot; 		/* retransmit counter */
  236: 	u_int16_t	sc_peer_mss;		/* peer's MSS */
  237: 	u_int16_t	sc_wnd;			/* advertised window */
  238: 	u_int8_t 	sc_requested_s_scale:4,
  239: 			sc_request_r_scale:4;
  240: 	u_int8_t	sc_flags;
  241: #define SCF_NOOPT	0x01			/* no TCP options */
  242: #define SCF_WINSCALE	0x02			/* negotiated window scaling */
  243: #define SCF_TIMESTAMP	0x04			/* negotiated timestamps */
  244: #define SCF_CC		0x08			/* negotiated CC */
  245: #define SCF_UNREACH	0x10			/* icmp unreachable received */
  246: #define SCF_KEEPROUTE	0x20			/* keep cloned route */
  247: 	TAILQ_ENTRY(syncache)	sc_hash;
  248: 	TAILQ_ENTRY(syncache)	sc_timerq;
  249: };
  250: 
  251: struct syncache_head {
  252: 	TAILQ_HEAD(, syncache)	sch_bucket;
  253: 	u_int		sch_length;
  254: };
  255:  
  256: /*
  257:  * The TAO cache entry which is stored in the protocol family specific
  258:  * portion of the route metrics.
  259:  */
  260: struct rmxp_tao {
  261: 	tcp_cc	tao_cc;			/* latest CC in valid SYN */
  262: 	tcp_cc	tao_ccsent;		/* latest CC sent to peer */
  263: 	u_short	tao_mssopt;		/* peer's cached MSS */
  264: #ifdef notyet
  265: 	u_short	tao_flags;		/* cache status flags */
  266: #define	TAOF_DONT	0x0001		/* peer doesn't understand rfc1644 */
  267: #define	TAOF_OK		0x0002		/* peer does understand rfc1644 */
  268: #define	TAOF_UNDEF	0		/* we don't know yet */
  269: #endif /* notyet */
  270: };
  271: #define rmx_taop(r)	((struct rmxp_tao *)(r).rmx_filler)
  272: 
  273: #define	intotcpcb(ip)	((struct tcpcb *)(ip)->inp_ppcb)
  274: #define	sototcpcb(so)	(intotcpcb(sotoinpcb(so)))
  275: 
  276: /*
  277:  * The smoothed round-trip time and estimated variance
  278:  * are stored as fixed point numbers scaled by the values below.
  279:  * For convenience, these scales are also used in smoothing the average
  280:  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
  281:  * With these scales, srtt has 3 bits to the right of the binary point,
  282:  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
  283:  * binary point, and is smoothed with an ALPHA of 0.75.
  284:  */
  285: #define	TCP_RTT_SCALE		32	/* multiplier for srtt; 3 bits frac. */
  286: #define	TCP_RTT_SHIFT		5	/* shift for srtt; 3 bits frac. */
  287: #define	TCP_RTTVAR_SCALE	16	/* multiplier for rttvar; 2 bits */
  288: #define	TCP_RTTVAR_SHIFT	4	/* shift for rttvar; 2 bits */
  289: #define	TCP_DELTA_SHIFT		2	/* see tcp_input.c */
  290: 
  291: /*
  292:  * The initial retransmission should happen at rtt + 4 * rttvar.
  293:  * Because of the way we do the smoothing, srtt and rttvar
  294:  * will each average +1/2 tick of bias.  When we compute
  295:  * the retransmit timer, we want 1/2 tick of rounding and
  296:  * 1 extra tick because of +-1/2 tick uncertainty in the
  297:  * firing of the timer.  The bias will give us exactly the
  298:  * 1.5 tick we need.  But, because the bias is
  299:  * statistical, we have to test that we don't drop below
  300:  * the minimum feasible timer (which is 2 ticks).
  301:  * This version of the macro adapted from a paper by Lawrence
  302:  * Brakmo and Larry Peterson which outlines a problem caused
  303:  * by insufficient precision in the original implementation,
  304:  * which results in inappropriately large RTO values for very
  305:  * fast networks.
  306:  */
  307: #define	TCP_REXMTVAL(tp) \
  308: 	max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
  309: 	  + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
  310: 
  311: /*
  312:  * TCB structure exported to user-land via sysctl(3).
  313:  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
  314:  * included.  Not all of our clients do.
  315:  */
  316: #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
  317: struct	xtcpcb {
  318: 	size_t	xt_len;
  319: 	struct	inpcb	xt_inp;
  320: 	struct	tcpcb	xt_tp;
  321: 	struct	xsocket	xt_socket;
  322: 	u_quad_t	xt_alignment_hack;
  323: };
  324: #endif
  325: 
  326: /*
  327:  * Names for TCP sysctl objects
  328:  */
  329: #define	TCPCTL_DO_RFC1323	1	/* use RFC-1323 extensions */
  330: #define	TCPCTL_DO_RFC1644	2	/* use RFC-1644 extensions */
  331: #define	TCPCTL_MSSDFLT		3	/* MSS default */
  332: #define TCPCTL_STATS		4	/* statistics (read-only) */
  333: #define	TCPCTL_RTTDFLT		5	/* default RTT estimate */
  334: #define	TCPCTL_KEEPIDLE		6	/* keepalive idle timer */
  335: #define	TCPCTL_KEEPINTVL	7	/* interval to send keepalives */
  336: #define	TCPCTL_SENDSPACE	8	/* send buffer space */
  337: #define	TCPCTL_RECVSPACE	9	/* receive buffer space */
  338: #define	TCPCTL_KEEPINIT		10	/* timeout for establishing syn */
  339: #define	TCPCTL_PCBLIST		11	/* list of all outstanding PCBs */
  340: #define	TCPCTL_DELACKTIME	12	/* time before sending delayed ACK */
  341: #define	TCPCTL_V6MSSDFLT	13	/* MSS default for IPv6 */
  342: #define	TCPCTL_MAXID		14
  343: 
  344: #define TCPCTL_NAMES { \
  345: 	{ 0, 0 }, \
  346: 	{ "rfc1323", CTLTYPE_INT }, \
  347: 	{ "rfc1644", CTLTYPE_INT }, \
  348: 	{ "mssdflt", CTLTYPE_INT }, \
  349: 	{ "stats", CTLTYPE_STRUCT }, \
  350: 	{ "rttdflt", CTLTYPE_INT }, \
  351: 	{ "keepidle", CTLTYPE_INT }, \
  352: 	{ "keepintvl", CTLTYPE_INT }, \
  353: 	{ "sendspace", CTLTYPE_INT }, \
  354: 	{ "recvspace", CTLTYPE_INT }, \
  355: 	{ "keepinit", CTLTYPE_INT }, \
  356: 	{ "pcblist", CTLTYPE_STRUCT }, \
  357: 	{ "delacktime", CTLTYPE_INT }, \
  358: 	{ "v6mssdflt", CTLTYPE_INT }, \
  359: }
  360: 
  361: #ifdef _KERNEL
  362: #ifdef SYSCTL_DECL
  363: SYSCTL_DECL(_net_inet_tcp);
  364: #endif
  365: 
  366: extern	struct inpcbinfo tcbinfo[];
  367: extern	int tcp_mssdflt;	/* XXX */
  368: extern	int tcp_delack_enabled;
  369: extern	int tcp_do_newreno;
  370: extern	int path_mtu_discovery;
  371: extern	int ss_fltsz;
  372: extern	int ss_fltsz_local;
  373: 
  374: int	 tcp_addrcpu(in_addr_t faddr, in_port_t fport,
  375: 	    in_addr_t laddr, in_port_t lport);
  376: void	 tcp_canceltimers (struct tcpcb *);
  377: struct tcpcb *
  378: 	 tcp_close (struct tcpcb *);
  379: void	 tcp_ctlinput (int, struct sockaddr *, void *);
  380: int	 tcp_ctloutput (struct socket *, struct sockopt *);
  381: struct lwkt_port *
  382: 	 tcp_cport(int cpu);
  383: struct tcpcb *
  384: 	 tcp_drop (struct tcpcb *, int);
  385: void	 tcp_drain (void);
  386: void	 tcp_fasttimo (void);
  387: struct rmxp_tao *
  388: 	 tcp_gettaocache (struct in_conninfo *);
  389: void	 tcp_init (void);
  390: void	 tcp_thread_init (void);
  391: void	 tcp_input (struct mbuf *, int, int);
  392: void	 tcp_mss (struct tcpcb *, int);
  393: int	 tcp_mssopt (struct tcpcb *);
  394: void	 tcp_drop_syn_sent (struct inpcb *, int);
  395: void	 tcp_mtudisc (struct inpcb *, int);
  396: struct tcpcb *
  397: 	 tcp_newtcpcb (struct inpcb *);
  398: int	 tcp_output (struct tcpcb *);
  399: void	 tcp_quench (struct inpcb *, int);
  400: void	 tcp_respond (struct tcpcb *, void *,
  401: 	    struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
  402: struct rtentry *
  403: 	 tcp_rtlookup (struct in_conninfo *);
  404: void	 tcp_save_congestion_state(struct tcpcb *tp);
  405: void	 tcp_revert_congestion_state(struct tcpcb *tp);
  406: void	 tcp_setpersist (struct tcpcb *);
  407: void	 tcp_slowtimo (void);
  408: struct tcptemp *
  409: 	 tcp_maketemplate (struct tcpcb *);
  410: void	 tcp_fillheaders (struct tcpcb *, void *, void *);
  411: struct lwkt_port *
  412: 	 tcp_soport(struct socket *, struct sockaddr *nam);
  413: struct tcpcb *
  414: 	 tcp_timers (struct tcpcb *, int);
  415: void	 tcp_trace (int, int, struct tcpcb *, void *, struct tcphdr *,
  416: 			int);
  417: void	 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
  418: void	 syncache_init(void);
  419: void	 syncache_unreach(struct in_conninfo *, struct tcphdr *);
  420: int	 syncache_expand(struct in_conninfo *, struct tcphdr *,
  421: 	     struct socket **, struct mbuf *);
  422: int	 syncache_add(struct in_conninfo *, struct tcpopt *,
  423: 	     struct tcphdr *, struct socket **, struct mbuf *);
  424: void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *);
  425: void	 syncache_badack(struct in_conninfo *);
  426: 
  427: extern	struct pr_usrreqs tcp_usrreqs;
  428: extern	u_long tcp_sendspace;
  429: extern	u_long tcp_recvspace;
  430: tcp_seq tcp_new_isn (struct tcpcb *);
  431: 
  432: #endif /* _KERNEL */
  433: 
  434: #endif /* _NETINET_TCP_VAR_H_ */