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tcp_var.h revision 1.167
      1 /*	$NetBSD: tcp_var.h,v 1.167 2011/05/25 23:17:44 gdt Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the project nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  *      @(#)COPYRIGHT   1.1 (NRL) 17 January 1995
     34  *
     35  * NRL grants permission for redistribution and use in source and binary
     36  * forms, with or without modification, of the software and documentation
     37  * created at NRL provided that the following conditions are met:
     38  *
     39  * 1. Redistributions of source code must retain the above copyright
     40  *    notice, this list of conditions and the following disclaimer.
     41  * 2. Redistributions in binary form must reproduce the above copyright
     42  *    notice, this list of conditions and the following disclaimer in the
     43  *    documentation and/or other materials provided with the distribution.
     44  * 3. All advertising materials mentioning features or use of this software
     45  *    must display the following acknowledgements:
     46  *      This product includes software developed by the University of
     47  *      California, Berkeley and its contributors.
     48  *      This product includes software developed at the Information
     49  *      Technology Division, US Naval Research Laboratory.
     50  * 4. Neither the name of the NRL nor the names of its contributors
     51  *    may be used to endorse or promote products derived from this software
     52  *    without specific prior written permission.
     53  *
     54  * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS
     55  * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     56  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     57  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL NRL OR
     58  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     59  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     60  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     61  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     62  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     63  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     64  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     65  *
     66  * The views and conclusions contained in the software and documentation
     67  * are those of the authors and should not be interpreted as representing
     68  * official policies, either expressed or implied, of the US Naval
     69  * Research Laboratory (NRL).
     70  */
     71 
     72 /*-
     73  * Copyright (c) 1997, 1998, 1999, 2001, 2005 The NetBSD Foundation, Inc.
     74  * All rights reserved.
     75  *
     76  * This code is derived from software contributed to The NetBSD Foundation
     77  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
     78  * NASA Ames Research Center.
     79  * This code is derived from software contributed to The NetBSD Foundation
     80  * by Charles M. Hannum.
     81  *
     82  * Redistribution and use in source and binary forms, with or without
     83  * modification, are permitted provided that the following conditions
     84  * are met:
     85  * 1. Redistributions of source code must retain the above copyright
     86  *    notice, this list of conditions and the following disclaimer.
     87  * 2. Redistributions in binary form must reproduce the above copyright
     88  *    notice, this list of conditions and the following disclaimer in the
     89  *    documentation and/or other materials provided with the distribution.
     90  *
     91  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     92  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     93  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     94  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     95  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     96  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     97  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     98  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     99  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    100  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    101  * POSSIBILITY OF SUCH DAMAGE.
    102  */
    103 
    104 /*
    105  * Copyright (c) 1982, 1986, 1993, 1994, 1995
    106  *	The Regents of the University of California.  All rights reserved.
    107  *
    108  * Redistribution and use in source and binary forms, with or without
    109  * modification, are permitted provided that the following conditions
    110  * are met:
    111  * 1. Redistributions of source code must retain the above copyright
    112  *    notice, this list of conditions and the following disclaimer.
    113  * 2. Redistributions in binary form must reproduce the above copyright
    114  *    notice, this list of conditions and the following disclaimer in the
    115  *    documentation and/or other materials provided with the distribution.
    116  * 3. Neither the name of the University nor the names of its contributors
    117  *    may be used to endorse or promote products derived from this software
    118  *    without specific prior written permission.
    119  *
    120  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
    121  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    122  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    123  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
    124  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    125  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
    126  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    127  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    128  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    129  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    130  * SUCH DAMAGE.
    131  *
    132  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
    133  */
    134 
    135 #ifndef _NETINET_TCP_VAR_H_
    136 #define _NETINET_TCP_VAR_H_
    137 
    138 #if defined(_KERNEL_OPT)
    139 #include "opt_inet.h"
    140 #include "opt_mbuftrace.h"
    141 #include "rnd.h"
    142 #endif
    143 
    144 /*
    145  * Kernel variables for tcp.
    146  */
    147 
    148 #include <sys/callout.h>
    149 
    150 #ifdef TCP_SIGNATURE
    151 /*
    152  * Defines which are needed by the xform_tcp module and tcp_[in|out]put
    153  * for SADB verification and lookup.
    154  */
    155 #define	TCP_SIGLEN	16	/* length of computed digest in bytes */
    156 #define	TCP_KEYLEN_MIN	1	/* minimum length of TCP-MD5 key */
    157 #define	TCP_KEYLEN_MAX	80	/* maximum length of TCP-MD5 key */
    158 /*
    159  * Only a single SA per host may be specified at this time. An SPI is
    160  * needed in order for the KEY_ALLOCSA() lookup to work.
    161  */
    162 #define	TCP_SIG_SPI	0x1000
    163 #endif /* TCP_SIGNATURE */
    164 
    165 /*
    166  * SACK option block.
    167  */
    168 struct sackblk {
    169 	tcp_seq left;		/* Left edge of sack block. */
    170 	tcp_seq right;		/* Right edge of sack block. */
    171 };
    172 
    173 TAILQ_HEAD(sackhead, sackhole);
    174 struct sackhole {
    175 	tcp_seq start;
    176 	tcp_seq end;
    177 	tcp_seq rxmit;
    178 
    179 	TAILQ_ENTRY(sackhole) sackhole_q;
    180 };
    181 
    182 /*
    183  * Tcp control block, one per tcp; fields:
    184  */
    185 struct tcpcb {
    186 	int	t_family;		/* address family on the wire */
    187 	struct ipqehead segq;		/* sequencing queue */
    188 	int	t_segqlen;		/* length of the above */
    189 	callout_t t_timer[TCPT_NTIMERS];/* tcp timers */
    190 	short	t_state;		/* state of this connection */
    191 	short	t_rxtshift;		/* log(2) of rexmt exp. backoff */
    192 	uint32_t t_rxtcur;		/* current retransmit value */
    193 	short	t_dupacks;		/* consecutive dup acks recd */
    194 	/*
    195 	 * t_partialacks:
    196 	 *	<0	not in fast recovery.
    197 	 *	==0	in fast recovery.  has not received partial acks
    198 	 *	>0	in fast recovery.  has received partial acks
    199 	 */
    200 	short	t_partialacks;		/* partials acks during fast rexmit */
    201 	u_short	t_peermss;		/* peer's maximum segment size */
    202 	u_short	t_ourmss;		/* our's maximum segment size */
    203 	u_short t_segsz;		/* current segment size in use */
    204 	char	t_force;		/* 1 if forcing out a byte */
    205 	u_int	t_flags;
    206 #define	TF_ACKNOW	0x0001		/* ack peer immediately */
    207 #define	TF_DELACK	0x0002		/* ack, but try to delay it */
    208 #define	TF_NODELAY	0x0004		/* don't delay packets to coalesce */
    209 #define	TF_NOOPT	0x0008		/* don't use tcp options */
    210 #define	TF_REQ_SCALE	0x0020		/* have/will request window scaling */
    211 #define	TF_RCVD_SCALE	0x0040		/* other side has requested scaling */
    212 #define	TF_REQ_TSTMP	0x0080		/* have/will request timestamps */
    213 #define	TF_RCVD_TSTMP	0x0100		/* a timestamp was received in SYN */
    214 #define	TF_SACK_PERMIT	0x0200		/* other side said I could SACK */
    215 #define	TF_SYN_REXMT	0x0400		/* rexmit timer fired on SYN */
    216 #define	TF_WILL_SACK	0x0800		/* try to use SACK */
    217 #define	TF_REASSEMBLING	0x1000		/* we're busy reassembling */
    218 #define	TF_DEAD		0x2000		/* dead and to-be-released */
    219 #define	TF_PMTUD_PEND	0x4000		/* Path MTU Discovery pending */
    220 #define	TF_ECN_PERMIT	0x10000		/* other side said is ECN-ready */
    221 #define	TF_ECN_SND_CWR	0x20000		/* ECN CWR in queue */
    222 #define	TF_ECN_SND_ECE	0x40000		/* ECN ECE in queue */
    223 #define	TF_SIGNATURE	0x400000	/* require MD5 digests (RFC2385) */
    224 
    225 
    226 	struct	mbuf *t_template;	/* skeletal packet for transmit */
    227 	struct	inpcb *t_inpcb;		/* back pointer to internet pcb */
    228 	struct	in6pcb *t_in6pcb;	/* back pointer to internet pcb */
    229 	callout_t t_delack_ch;		/* delayed ACK callout */
    230 /*
    231  * The following fields are used as in the protocol specification.
    232  * See RFC793, Dec. 1981, page 21.
    233  */
    234 /* send sequence variables */
    235 	tcp_seq	snd_una;		/* send unacknowledged */
    236 	tcp_seq	snd_nxt;		/* send next */
    237 	tcp_seq	snd_up;			/* send urgent pointer */
    238 	tcp_seq	snd_wl1;		/* window update seg seq number */
    239 	tcp_seq	snd_wl2;		/* window update seg ack number */
    240 	tcp_seq	iss;			/* initial send sequence number */
    241 	u_long	snd_wnd;		/* send window */
    242 /*
    243  * snd_recover
    244  * 	it's basically same as the "recover" variable in RFC 2852 (NewReno).
    245  * 	when entering fast retransmit, it's set to snd_max.
    246  * 	newreno uses this to detect partial ack.
    247  * snd_high
    248  * 	it's basically same as the "send_high" variable in RFC 2852 (NewReno).
    249  * 	on each RTO, it's set to snd_max.
    250  * 	newreno uses this to avoid false fast retransmits.
    251  */
    252 	tcp_seq snd_recover;
    253 	tcp_seq	snd_high;
    254 /* receive sequence variables */
    255 	u_long	rcv_wnd;		/* receive window */
    256 	tcp_seq	rcv_nxt;		/* receive next */
    257 	tcp_seq	rcv_up;			/* receive urgent pointer */
    258 	tcp_seq	irs;			/* initial receive sequence number */
    259 /*
    260  * Additional variables for this implementation.
    261  */
    262 /* receive variables */
    263 	tcp_seq	rcv_adv;		/* advertised window */
    264 
    265 /*
    266  * retransmit variables
    267  *
    268  * snd_max
    269  * 	the highest sequence number we've ever sent.
    270  *	used to recognize retransmits.
    271  */
    272 	tcp_seq	snd_max;
    273 
    274 /* congestion control (for slow start, source quench, retransmit after loss) */
    275 	u_long	snd_cwnd;		/* congestion-controlled window */
    276 	u_long	snd_ssthresh;		/* snd_cwnd size threshhold for
    277 					 * for slow start exponential to
    278 					 * linear switch
    279 					 */
    280 /* auto-sizing variables */
    281 	u_int rfbuf_cnt;		/* recv buffer autoscaling byte count */
    282 	uint32_t rfbuf_ts;		/* recv buffer autoscaling timestamp */
    283 
    284 /*
    285  * transmit timing stuff.  See below for scale of srtt and rttvar.
    286  * "Variance" is actually smoothed difference.
    287  */
    288 	uint32_t t_rcvtime;		/* time last segment received */
    289 	uint32_t t_rtttime;		/* time we started measuring rtt */
    290 	tcp_seq	t_rtseq;		/* sequence number being timed */
    291 	int32_t	t_srtt;			/* smoothed round-trip time */
    292 	int32_t	t_rttvar;		/* variance in round-trip time */
    293 	uint32_t t_rttmin;		/* minimum rtt allowed */
    294 	u_long	max_sndwnd;		/* largest window peer has offered */
    295 
    296 /* out-of-band data */
    297 	char	t_oobflags;		/* have some */
    298 	char	t_iobc;			/* input character */
    299 #define	TCPOOB_HAVEDATA	0x01
    300 #define	TCPOOB_HADDATA	0x02
    301 	short	t_softerror;		/* possible error not yet reported */
    302 
    303 /* RFC 1323 variables */
    304 	u_char	snd_scale;		/* window scaling for send window */
    305 	u_char	rcv_scale;		/* window scaling for recv window */
    306 	u_char	request_r_scale;	/* pending window scaling */
    307 	u_char	requested_s_scale;
    308 	u_int32_t ts_recent;		/* timestamp echo data */
    309 	u_int32_t ts_recent_age;	/* when last updated */
    310 	u_int32_t ts_timebase;		/* our timebase */
    311 	tcp_seq	last_ack_sent;
    312 
    313 /* RFC 3465 variables */
    314 	u_long	t_bytes_acked;		/* ABC "bytes_acked" parameter */
    315 
    316 /* SACK stuff */
    317 #define TCP_SACK_MAX 3
    318 #define TCPSACK_NONE 0
    319 #define TCPSACK_HAVED 1
    320 	u_char rcv_sack_flags;		/* SACK flags. */
    321 	struct sackblk rcv_dsack_block;	/* RX D-SACK block. */
    322 	struct ipqehead timeq;		/* time sequenced queue. */
    323 	struct sackhead snd_holes;	/* TX SACK holes. */
    324 	int	snd_numholes;		/* Number of TX SACK holes. */
    325 	tcp_seq rcv_lastsack;		/* last seq number(+1) sack'd by rcv'r*/
    326 	tcp_seq sack_newdata;		/* New data xmitted in this recovery
    327 					   episode starts at this seq number*/
    328 	tcp_seq snd_fack;		/* FACK TCP.  Forward-most data held by
    329 					   peer. */
    330 
    331 /* pointer for syn cache entries*/
    332 	LIST_HEAD(, syn_cache) t_sc;	/* list of entries by this tcb */
    333 
    334 /* prediction of next mbuf when using large window sizes */
    335 	struct	mbuf *t_lastm;		/* last mbuf that data was sent from */
    336 	int	t_inoff;		/* data offset in previous mbuf */
    337 	int	t_lastoff;		/* last data address in mbuf chain */
    338 	int	t_lastlen;		/* last length read from mbuf chain */
    339 
    340 /* Path-MTU discovery blackhole detection */
    341 	int t_mtudisc;			/* perform mtudisc for this tcb */
    342 /* Path-MTU Discovery Information */
    343 	u_int	t_pmtud_mss_acked;	/* MSS acked, lower bound for MTU */
    344 	u_int	t_pmtud_mtu_sent;	/* MTU used, upper bound for MTU */
    345 	tcp_seq	t_pmtud_th_seq;		/* TCP SEQ from ICMP payload */
    346 	u_int	t_pmtud_nextmtu;	/* Advertised Next-Hop MTU from ICMP */
    347 	u_short	t_pmtud_ip_len;		/* IP length from ICMP payload */
    348 	u_short	t_pmtud_ip_hl;		/* IP header length from ICMP payload */
    349 
    350 	uint8_t t_ecn_retries;		/* # of ECN setup retries */
    351 
    352 	const struct tcp_congctl *t_congctl;	/* per TCB congctl algorithm */
    353 
    354 	/* Keepalive per socket */
    355 	u_int	t_keepinit;
    356 	u_int	t_keepidle;
    357 	u_int	t_keepintvl;
    358 	u_int	t_keepcnt;
    359 	u_int	t_maxidle;		/* t_keepcnt * t_keepintvl */
    360 
    361 	u_int	t_msl;			/* MSL to use for this connexion */
    362 };
    363 
    364 /*
    365  * Macros to aid ECN TCP.
    366  */
    367 #define TCP_ECN_ALLOWED(tp)	(tp->t_flags & TF_ECN_PERMIT)
    368 
    369 /*
    370  * Macros to aid SACK/FACK TCP.
    371  */
    372 #define TCP_SACK_ENABLED(tp)	(tp->t_flags & TF_WILL_SACK)
    373 #define TCP_FACK_FASTRECOV(tp)	\
    374 	(TCP_SACK_ENABLED(tp) && \
    375 	(SEQ_GT(tp->snd_fack, tp->snd_una + tcprexmtthresh * tp->t_segsz)))
    376 
    377 #ifdef _KERNEL
    378 /*
    379  * TCP reassembly queue locks.
    380  */
    381 static __inline int tcp_reass_lock_try (struct tcpcb *)
    382 	__unused;
    383 static __inline void tcp_reass_unlock (struct tcpcb *)
    384 	__unused;
    385 
    386 static __inline int
    387 tcp_reass_lock_try(struct tcpcb *tp)
    388 {
    389 	int s;
    390 
    391 	/*
    392 	 * Use splvm() -- we're blocking things that would cause
    393 	 * mbuf allocation.
    394 	 */
    395 	s = splvm();
    396 	if (tp->t_flags & TF_REASSEMBLING) {
    397 		splx(s);
    398 		return (0);
    399 	}
    400 	tp->t_flags |= TF_REASSEMBLING;
    401 	splx(s);
    402 	return (1);
    403 }
    404 
    405 static __inline void
    406 tcp_reass_unlock(struct tcpcb *tp)
    407 {
    408 	int s;
    409 
    410 	s = splvm();
    411 	tp->t_flags &= ~TF_REASSEMBLING;
    412 	splx(s);
    413 }
    414 
    415 #ifdef DIAGNOSTIC
    416 #define	TCP_REASS_LOCK(tp)						\
    417 do {									\
    418 	if (tcp_reass_lock_try(tp) == 0) {				\
    419 		printf("%s:%d: tcpcb %p reass already locked\n",	\
    420 		    __FILE__, __LINE__, tp);				\
    421 		panic("tcp_reass_lock");				\
    422 	}								\
    423 } while (/*CONSTCOND*/ 0)
    424 #define	TCP_REASS_LOCK_CHECK(tp)					\
    425 do {									\
    426 	if (((tp)->t_flags & TF_REASSEMBLING) == 0) {			\
    427 		printf("%s:%d: tcpcb %p reass lock not held\n",		\
    428 		    __FILE__, __LINE__, tp);				\
    429 		panic("tcp reass lock check");				\
    430 	}								\
    431 } while (/*CONSTCOND*/ 0)
    432 #else
    433 #define	TCP_REASS_LOCK(tp)	(void) tcp_reass_lock_try((tp))
    434 #define	TCP_REASS_LOCK_CHECK(tp) /* nothing */
    435 #endif
    436 
    437 #define	TCP_REASS_UNLOCK(tp)	tcp_reass_unlock((tp))
    438 #endif /* _KERNEL */
    439 
    440 /*
    441  * Queue for delayed ACK processing.
    442  */
    443 #ifdef _KERNEL
    444 extern int tcp_delack_ticks;
    445 void	tcp_delack(void *);
    446 
    447 #define TCP_RESTART_DELACK(tp)						\
    448 	callout_reset(&(tp)->t_delack_ch, tcp_delack_ticks,		\
    449 	    tcp_delack, tp)
    450 
    451 #define	TCP_SET_DELACK(tp)						\
    452 do {									\
    453 	if (((tp)->t_flags & TF_DELACK) == 0) {				\
    454 		(tp)->t_flags |= TF_DELACK;				\
    455 		TCP_RESTART_DELACK(tp);					\
    456 	}								\
    457 } while (/*CONSTCOND*/0)
    458 
    459 #define	TCP_CLEAR_DELACK(tp)						\
    460 do {									\
    461 	if ((tp)->t_flags & TF_DELACK) {				\
    462 		(tp)->t_flags &= ~TF_DELACK;				\
    463 		callout_stop(&(tp)->t_delack_ch);			\
    464 	}								\
    465 } while (/*CONSTCOND*/0)
    466 #endif /* _KERNEL */
    467 
    468 /*
    469  * Compute the current timestamp for a connection.
    470  */
    471 #define	TCP_TIMESTAMP(tp)	(tcp_now - (tp)->ts_timebase)
    472 
    473 /*
    474  * Handy way of passing around TCP option info.
    475  */
    476 struct tcp_opt_info {
    477 	int		ts_present;
    478 	u_int32_t	ts_val;
    479 	u_int32_t	ts_ecr;
    480 	u_int16_t	maxseg;
    481 };
    482 
    483 #define	TOF_SIGNATURE	0x0040		/* signature option present */
    484 #define	TOF_SIGLEN	0x0080		/* sigature length valid (RFC2385) */
    485 
    486 /*
    487  * Data for the TCP compressed state engine.
    488  */
    489 union syn_cache_sa {
    490 	struct sockaddr sa;
    491 	struct sockaddr_in sin;
    492 #if 1 /*def INET6*/
    493 	struct sockaddr_in6 sin6;
    494 #endif
    495 };
    496 
    497 struct syn_cache {
    498 	TAILQ_ENTRY(syn_cache) sc_bucketq;	/* link on bucket list */
    499 	callout_t sc_timer;			/* rexmt timer */
    500 	struct route sc_route;
    501 	long sc_win;				/* advertised window */
    502 	int sc_bucketidx;			/* our bucket index */
    503 	u_int32_t sc_hash;
    504 	u_int32_t sc_timestamp;			/* timestamp from SYN */
    505 	u_int32_t sc_timebase;			/* our local timebase */
    506 	union syn_cache_sa sc_src;
    507 	union syn_cache_sa sc_dst;
    508 	tcp_seq sc_irs;
    509 	tcp_seq sc_iss;
    510 	u_int sc_rxtcur;			/* current rxt timeout */
    511 	u_int sc_rxttot;			/* total time spend on queues */
    512 	u_short sc_rxtshift;			/* for computing backoff */
    513 	u_short sc_flags;
    514 
    515 #define	SCF_UNREACH		0x0001		/* we've had an unreach error */
    516 #define	SCF_TIMESTAMP		0x0002		/* peer will do timestamps */
    517 #define	SCF_DEAD		0x0004		/* this entry to be released */
    518 #define SCF_SACK_PERMIT		0x0008		/* peer will do SACK */
    519 #define SCF_ECN_PERMIT		0x0010		/* peer will do ECN */
    520 #define SCF_SIGNATURE	0x40			/* send MD5 digests */
    521 
    522 	struct mbuf *sc_ipopts;			/* IP options */
    523 	u_int16_t sc_peermaxseg;
    524 	u_int16_t sc_ourmaxseg;
    525 	u_int8_t sc_request_r_scale	: 4,
    526 		 sc_requested_s_scale	: 4;
    527 
    528 	struct tcpcb *sc_tp;			/* tcb for listening socket */
    529 	LIST_ENTRY(syn_cache) sc_tpq;		/* list of entries by same tp */
    530 };
    531 
    532 struct syn_cache_head {
    533 	TAILQ_HEAD(, syn_cache) sch_bucket;	/* bucket entries */
    534 	u_short sch_length;			/* # entries in bucket */
    535 };
    536 
    537 #define	intotcpcb(ip)	((struct tcpcb *)(ip)->inp_ppcb)
    538 #ifdef INET6
    539 #define	in6totcpcb(ip)	((struct tcpcb *)(ip)->in6p_ppcb)
    540 #endif
    541 #ifndef INET6
    542 #define	sototcpcb(so)	(intotcpcb(sotoinpcb(so)))
    543 #else
    544 #define	sototcpcb(so)	(((so)->so_proto->pr_domain->dom_family == AF_INET) \
    545 				? intotcpcb(sotoinpcb(so)) \
    546 				: in6totcpcb(sotoin6pcb(so)))
    547 #endif
    548 
    549 /*
    550  * See RFC2988 for a discussion of RTO calculation; comments assume
    551  * familiarity with that document.
    552  *
    553  * The smoothed round-trip time and estimated variance are stored as
    554  * fixed point numbers.  Historically, srtt was scaled by
    555  * TCP_RTT_SHIFT bits, and rttvar by TCP_RTTVAR_SHIFT bits.  Because
    556  * the values coincide with the alpha and beta parameters suggested
    557  * for RTO calculation (1/8 for srtt, 1/4 for rttvar), the combination
    558  * of computing 1/8 of the new value and transforming it to the
    559  * fixed-point representation required zero instructions.  However,
    560  * the storage representations no longer coincide with the alpha/beta
    561  * shifts; instead, more fractional bits are present.
    562  *
    563  * The storage representation of srtt is 1/32 slow ticks, or 1/64 s.
    564  * (The assumption that a slow tick is 500 ms should not be present in
    565  * the code.)
    566  *
    567  * The storage representation of rttvar is 1/16 slow ticks, or 1/32 s.
    568  * There may be some confusion about this in the code.
    569  *
    570  * For historical reasons, these scales are also used in smoothing the
    571  * average (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
    572  * This results in alpha of 0.125 and beta of 0.25, following RFC2988
    573  * section 2.3
    574  *
    575  * XXX Change SHIFT values to LGWEIGHT and REP_SHIFT, and adjust
    576  * the code to use the correct ones.
    577  */
    578 #define	TCP_RTT_SHIFT		3	/* shift for srtt; 3 bits frac. */
    579 #define	TCP_RTTVAR_SHIFT	2	/* multiplier for rttvar; 2 bits */
    580 
    581 /*
    582  * Compute TCP retransmission timer, following RFC2988.
    583  * This macro returns a value in slow timeout ticks.
    584  *
    585  * Section 2.2 requires that the RTO value be
    586  *  srtt + max(G, 4*RTTVAR)
    587  * where G is the clock granularity.
    588  *
    589  * This comment has not necessarily been updated for the new storage
    590  * representation:
    591  *
    592  * Because of the way we do the smoothing, srtt and rttvar
    593  * will each average +1/2 tick of bias.  When we compute
    594  * the retransmit timer, we want 1/2 tick of rounding and
    595  * 1 extra tick because of +-1/2 tick uncertainty in the
    596  * firing of the timer.  The bias will give us exactly the
    597  * 1.5 tick we need.  But, because the bias is
    598  * statistical, we have to test that we don't drop below
    599  * the minimum feasible timer (which is 2 ticks).
    600  * This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT
    601  * is the same as the multiplier for rttvar.
    602  *
    603  * This macro appears to be wrong; it should be checking rttvar*4 in
    604  * ticks and making sure we use 1 instead if rttvar*4 rounds to 0.  It
    605  * appears to be treating srtt as being in the old storage
    606  * representation, resulting in a factor of 4 extra.
    607  */
    608 #define	TCP_REXMTVAL(tp) \
    609 	((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2)
    610 
    611 /*
    612  * Compute the initial window for slow start.
    613  */
    614 #define	TCP_INITIAL_WINDOW(iw, segsz) \
    615 	(((iw) == 0) ? (min(4 * (segsz), max(2 * (segsz), 4380))) : \
    616 	 ((segsz) * (iw)))
    617 
    618 /*
    619  * TCP statistics.
    620  * Each counter is an unsigned 64-bit value.
    621  *
    622  * Many of these should be kept per connection, but that's inconvenient
    623  * at the moment.
    624  */
    625 #define	TCP_STAT_CONNATTEMPT	0	/* connections initiated */
    626 #define	TCP_STAT_ACCEPTS	1	/* connections accepted */
    627 #define	TCP_STAT_CONNECTS	2	/* connections established */
    628 #define	TCP_STAT_DROPS		3	/* connections dropped */
    629 #define	TCP_STAT_CONNDROPS	4	/* embryonic connections dropped */
    630 #define	TCP_STAT_CLOSED		5	/* conn. closed (includes drops) */
    631 #define	TCP_STAT_SEGSTIMED	6	/* segs where we tried to get rtt */
    632 #define	TCP_STAT_RTTUPDATED	7	/* times we succeeded */
    633 #define	TCP_STAT_DELACK		8	/* delayed ACKs sent */
    634 #define	TCP_STAT_TIMEOUTDROP	9	/* conn. dropped in rxmt timeout */
    635 #define	TCP_STAT_REXMTTIMEO	10	/* retransmit timeouts */
    636 #define	TCP_STAT_PERSISTTIMEO	11	/* persist timeouts */
    637 #define	TCP_STAT_KEEPTIMEO	12	/* keepalive timeouts */
    638 #define	TCP_STAT_KEEPPROBE	13	/* keepalive probes sent */
    639 #define	TCP_STAT_KEEPDROPS	14	/* connections dropped in keepalive */
    640 #define	TCP_STAT_PERSISTDROPS	15	/* connections dropped in persist */
    641 #define	TCP_STAT_CONNSDRAINED	16	/* connections drained due to memory
    642 					   shortage */
    643 #define	TCP_STAT_PMTUBLACKHOLE	17	/* PMTUD blackhole detected */
    644 #define	TCP_STAT_SNDTOTAL	18	/* total packets sent */
    645 #define	TCP_STAT_SNDPACK	19	/* data packlets sent */
    646 #define	TCP_STAT_SNDBYTE	20	/* data bytes sent */
    647 #define	TCP_STAT_SNDREXMITPACK	21	/* data packets retransmitted */
    648 #define	TCP_STAT_SNDREXMITBYTE	22	/* data bytes retransmitted */
    649 #define	TCP_STAT_SNDACKS	23	/* ACK-only packets sent */
    650 #define	TCP_STAT_SNDPROBE	24	/* window probes sent */
    651 #define	TCP_STAT_SNDURG		25	/* packets sent with URG only */
    652 #define	TCP_STAT_SNDWINUP	26	/* window update-only packets sent */
    653 #define	TCP_STAT_SNDCTRL	27	/* control (SYN|FIN|RST) packets sent */
    654 #define	TCP_STAT_RCVTOTAL	28	/* total packets received */
    655 #define	TCP_STAT_RCVPACK	29	/* packets received in sequence */
    656 #define	TCP_STAT_RCVBYTE	30	/* bytes received in sequence */
    657 #define	TCP_STAT_RCVBADSUM	31	/* packets received with cksum errs */
    658 #define	TCP_STAT_RCVBADOFF	32	/* packets received with bad offset */
    659 #define	TCP_STAT_RCVMEMDROP	33	/* packets dropped for lack of memory */
    660 #define	TCP_STAT_RCVSHORT	34	/* packets received too short */
    661 #define	TCP_STAT_RCVDUPPACK	35	/* duplicate-only packets received */
    662 #define	TCP_STAT_RCVDUPBYTE	36	/* duplicate-only bytes received */
    663 #define	TCP_STAT_RCVPARTDUPPACK	37	/* packets with some duplicate data */
    664 #define	TCP_STAT_RCVPARTDUPBYTE	38	/* dup. bytes in part-dup. packets */
    665 #define	TCP_STAT_RCVOOPACK	39	/* out-of-order packets received */
    666 #define	TCP_STAT_RCVOOBYTE	40	/* out-of-order bytes received */
    667 #define	TCP_STAT_RCVPACKAFTERWIN 41	/* packets with data after window */
    668 #define	TCP_STAT_RCVBYTEAFTERWIN 42	/* bytes received after window */
    669 #define	TCP_STAT_RCVAFTERCLOSE	43	/* packets received after "close" */
    670 #define	TCP_STAT_RCVWINPROBE	44	/* rcvd window probe packets */
    671 #define	TCP_STAT_RCVDUPACK	45	/* rcvd duplicate ACKs */
    672 #define	TCP_STAT_RCVACKTOOMUCH	46	/* rcvd ACKs for unsent data */
    673 #define	TCP_STAT_RCVACKPACK	47	/* rcvd ACK packets */
    674 #define	TCP_STAT_RCVACKBYTE	48	/* bytes ACKed by rcvd ACKs */
    675 #define	TCP_STAT_RCVWINUPD	49	/* rcvd window update packets */
    676 #define	TCP_STAT_PAWSDROP	50	/* segments dropped due to PAWS */
    677 #define	TCP_STAT_PREDACK	51	/* times hdr predict OK for ACKs */
    678 #define	TCP_STAT_PREDDAT	52	/* times hdr predict OK for data pkts */
    679 #define	TCP_STAT_PCBHASHMISS	53	/* input packets missing PCB hash */
    680 #define	TCP_STAT_NOPORT		54	/* no socket on port */
    681 #define	TCP_STAT_BADSYN		55	/* received ACK for which we have
    682 					   no SYN in compressed state */
    683 #define	TCP_STAT_DELAYED_FREE	56	/* delayed pool_put() of tcpcb */
    684 #define	TCP_STAT_SC_ADDED	57	/* # of sc entries added */
    685 #define	TCP_STAT_SC_COMPLETED	58	/* # of sc connections completed */
    686 #define	TCP_STAT_SC_TIMED_OUT	59	/* # of sc entries timed out */
    687 #define	TCP_STAT_SC_OVERFLOWED	60	/* # of sc drops due to overflow */
    688 #define	TCP_STAT_SC_RESET	61	/* # of sc drops due to RST */
    689 #define	TCP_STAT_SC_UNREACH	62	/* # of sc drops due to ICMP unreach */
    690 #define	TCP_STAT_SC_BUCKETOVERFLOW 63	/* # of sc drops due to bucket ovflow */
    691 #define	TCP_STAT_SC_ABORTED	64	/* # of sc entries aborted (no mem) */
    692 #define	TCP_STAT_SC_DUPESYN	65	/* # of duplicate SYNs received */
    693 #define	TCP_STAT_SC_DROPPED	66	/* # of SYNs dropped (no route/mem) */
    694 #define	TCP_STAT_SC_COLLISIONS	67	/* # of sc hash collisions */
    695 #define	TCP_STAT_SC_RETRANSMITTED 68	/* # of sc retransmissions */
    696 #define	TCP_STAT_SC_DELAYED_FREE 69	/* # of delayed pool_put()s */
    697 #define	TCP_STAT_SELFQUENCH	70	/* # of ENOBUFS we get on output */
    698 #define	TCP_STAT_BADSIG		71	/* # of drops due to bad signature */
    699 #define	TCP_STAT_GOODSIG	72	/* # of packets with good signature */
    700 #define	TCP_STAT_ECN_SHS	73	/* # of successful ECN handshakes */
    701 #define	TCP_STAT_ECN_CE		74	/* # of packets with CE bit */
    702 #define	TCP_STAT_ECN_ECT	75	/* # of packets with ECT(0) bit */
    703 
    704 #define	TCP_NSTATS		76
    705 
    706 /*
    707  * Names for TCP sysctl objects.
    708  */
    709 #define	TCPCTL_RFC1323		1	/* RFC1323 timestamps/scaling */
    710 #define	TCPCTL_SENDSPACE	2	/* default send buffer */
    711 #define	TCPCTL_RECVSPACE	3	/* default recv buffer */
    712 #define	TCPCTL_MSSDFLT		4	/* default seg size */
    713 #define	TCPCTL_SYN_CACHE_LIMIT	5	/* max size of comp. state engine */
    714 #define	TCPCTL_SYN_BUCKET_LIMIT	6	/* max size of hash bucket */
    715 #if 0	/*obsoleted*/
    716 #define	TCPCTL_SYN_CACHE_INTER	7	/* interval of comp. state timer */
    717 #endif
    718 #define	TCPCTL_INIT_WIN		8	/* initial window */
    719 #define	TCPCTL_MSS_IFMTU	9	/* mss from interface, not in_maxmtu */
    720 #define	TCPCTL_SACK		10	/* RFC2018 selective acknowledgement */
    721 #define	TCPCTL_WSCALE		11	/* RFC1323 window scaling */
    722 #define	TCPCTL_TSTAMP		12	/* RFC1323 timestamps */
    723 #define	TCPCTL_COMPAT_42	13	/* 4.2BSD TCP bug work-arounds */
    724 #define	TCPCTL_CWM		14	/* Congestion Window Monitoring */
    725 #define	TCPCTL_CWM_BURSTSIZE	15	/* burst size allowed by CWM */
    726 #define	TCPCTL_ACK_ON_PUSH	16	/* ACK immediately on PUSH */
    727 #define	TCPCTL_KEEPIDLE		17	/* keepalive idle time */
    728 #define	TCPCTL_KEEPINTVL	18	/* keepalive probe interval */
    729 #define	TCPCTL_KEEPCNT		19	/* keepalive count */
    730 #define	TCPCTL_SLOWHZ		20	/* PR_SLOWHZ (read-only) */
    731 #define	TCPCTL_NEWRENO		21	/* NewReno Congestion Control */
    732 #define TCPCTL_LOG_REFUSED	22	/* Log refused connections */
    733 #if 0	/*obsoleted*/
    734 #define	TCPCTL_RSTRATELIMIT	23	/* RST rate limit */
    735 #endif
    736 #define	TCPCTL_RSTPPSLIMIT	24	/* RST pps limit */
    737 #define	TCPCTL_DELACK_TICKS	25	/* # ticks to delay ACK */
    738 #define	TCPCTL_INIT_WIN_LOCAL	26	/* initial window for local nets */
    739 #define	TCPCTL_IDENT		27	/* rfc 931 identd */
    740 #define	TCPCTL_ACKDROPRATELIMIT	28	/* SYN/RST -> ACK rate limit */
    741 #define	TCPCTL_LOOPBACKCKSUM	29	/* do TCP checksum on loopback */
    742 #define	TCPCTL_STATS		30	/* TCP statistics */
    743 #define	TCPCTL_DEBUG		31	/* TCP debug sockets */
    744 #define	TCPCTL_DEBX		32	/* # of tcp debug sockets */
    745 #define	TCPCTL_DROP		33	/* drop tcp connection */
    746 #define	TCPCTL_MSL		34	/* Max Segment Life */
    747 #define	TCPCTL_MAXID		35
    748 
    749 #define	TCPCTL_NAMES { \
    750 	{ 0, 0 }, \
    751 	{ "rfc1323",	CTLTYPE_INT }, \
    752 	{ "sendspace",	CTLTYPE_INT }, \
    753 	{ "recvspace",	CTLTYPE_INT }, \
    754 	{ "mssdflt",	CTLTYPE_INT }, \
    755 	{ "syn_cache_limit", CTLTYPE_INT }, \
    756 	{ "syn_bucket_limit", CTLTYPE_INT }, \
    757 	{ 0, 0 },\
    758 	{ "init_win", CTLTYPE_INT }, \
    759 	{ "mss_ifmtu", CTLTYPE_INT }, \
    760 	{ "sack", CTLTYPE_INT }, \
    761 	{ "win_scale", CTLTYPE_INT }, \
    762 	{ "timestamps", CTLTYPE_INT }, \
    763 	{ "compat_42", CTLTYPE_INT }, \
    764 	{ "cwm", CTLTYPE_INT }, \
    765 	{ "cwm_burstsize", CTLTYPE_INT }, \
    766 	{ "ack_on_push", CTLTYPE_INT }, \
    767 	{ "keepidle",	CTLTYPE_INT }, \
    768 	{ "keepintvl",	CTLTYPE_INT }, \
    769 	{ "keepcnt",	CTLTYPE_INT }, \
    770 	{ "slowhz",	CTLTYPE_INT }, \
    771 	{ 0, 0 }, \
    772 	{ "log_refused",CTLTYPE_INT }, \
    773 	{ 0, 0 }, \
    774 	{ "rstppslimit", CTLTYPE_INT }, \
    775 	{ "delack_ticks", CTLTYPE_INT }, \
    776 	{ "init_win_local", CTLTYPE_INT }, \
    777 	{ "ident", CTLTYPE_STRUCT }, \
    778 	{ "ackdropppslimit", CTLTYPE_INT }, \
    779 	{ "do_loopback_cksum", CTLTYPE_INT }, \
    780 	{ "stats", CTLTYPE_STRUCT }, \
    781 	{ "debug", CTLTYPE_STRUCT }, \
    782 	{ "debx", CTLTYPE_INT }, \
    783 	{ "drop", CTLTYPE_STRUCT }, \
    784 	{ "msl", CTLTYPE_INT }, \
    785 }
    786 
    787 #ifdef _KERNEL
    788 extern	struct inpcbtable tcbtable;	/* head of queue of active tcpcb's */
    789 extern	u_int32_t tcp_now;	/* for RFC 1323 timestamps */
    790 extern	int tcp_do_rfc1323;	/* enabled/disabled? */
    791 extern	int tcp_do_sack;	/* SACK enabled/disabled? */
    792 extern	int tcp_do_win_scale;	/* RFC1323 window scaling enabled/disabled? */
    793 extern	int tcp_do_timestamps;	/* RFC1323 timestamps enabled/disabled? */
    794 extern	int tcp_mssdflt;	/* default seg size */
    795 extern	int tcp_minmss;		/* minimal seg size */
    796 extern  int tcp_msl;		/* max segment life */
    797 extern	int tcp_init_win;	/* initial window */
    798 extern	int tcp_init_win_local;	/* initial window for local nets */
    799 extern	int tcp_mss_ifmtu;	/* take MSS from interface, not in_maxmtu */
    800 extern	int tcp_compat_42;	/* work around ancient broken TCP peers */
    801 extern	int tcp_cwm;		/* enable Congestion Window Monitoring */
    802 extern	int tcp_cwm_burstsize;	/* burst size allowed by CWM */
    803 extern	int tcp_ack_on_push;	/* ACK immediately on PUSH */
    804 extern	int tcp_syn_cache_limit; /* max entries for compressed state engine */
    805 extern	int tcp_syn_bucket_limit;/* max entries per hash bucket */
    806 extern	int tcp_log_refused;	/* log refused connections */
    807 extern	int tcp_do_ecn;		/* TCP ECN enabled/disabled? */
    808 extern	int tcp_ecn_maxretries;	/* Max ECN setup retries */
    809 #if NRND > 0
    810 extern	int tcp_do_rfc1948;	/* ISS by cryptographic hash */
    811 #endif
    812 extern int tcp_sack_tp_maxholes;	/* Max holes per connection. */
    813 extern int tcp_sack_globalmaxholes;	/* Max holes per system. */
    814 extern int tcp_sack_globalholes;	/* Number of holes present. */
    815 extern int tcp_do_abc;			/* RFC3465 ABC enabled/disabled? */
    816 extern int tcp_abc_aggressive;		/* 1: L=2*SMSS  0: L=1*SMSS */
    817 
    818 extern int tcp_msl_enable;		/* enable TIME_WAIT truncation	*/
    819 extern int tcp_msl_loop;		/* MSL for loopback		*/
    820 extern int tcp_msl_local;		/* MSL for 'local'		*/
    821 extern int tcp_msl_remote;		/* MSL otherwise		*/
    822 extern int tcp_msl_remote_threshold;	/* RTT threshold		*/
    823 extern int tcp_rttlocal;		/* Use RTT to decide who's 'local' */
    824 extern int tcp4_vtw_enable;
    825 extern int tcp6_vtw_enable;
    826 extern int tcp_vtw_was_enabled;
    827 extern int tcp_vtw_entries;
    828 
    829 extern	int tcp_rst_ppslim;
    830 extern	int tcp_ackdrop_ppslim;
    831 
    832 extern	int tcp_syn_cache_size;
    833 extern	struct syn_cache_head tcp_syn_cache[];
    834 extern	u_long syn_cache_count;
    835 
    836 #ifdef MBUFTRACE
    837 extern	struct mowner tcp_rx_mowner;
    838 extern	struct mowner tcp_tx_mowner;
    839 extern	struct mowner tcp_reass_mowner;
    840 extern	struct mowner tcp_sock_mowner;
    841 extern	struct mowner tcp_sock_rx_mowner;
    842 extern	struct mowner tcp_sock_tx_mowner;
    843 extern	struct mowner tcp_mowner;
    844 #endif
    845 
    846 extern int tcp_do_autorcvbuf;
    847 extern int tcp_autorcvbuf_inc;
    848 extern int tcp_autorcvbuf_max;
    849 extern int tcp_do_autosndbuf;
    850 extern int tcp_autosndbuf_inc;
    851 extern int tcp_autosndbuf_max;
    852 
    853 
    854 #define	TCPCTL_VARIABLES { \
    855 	{ 0 },					\
    856 	{ 1, 0, &tcp_do_rfc1323 },		\
    857 	{ 1, 0, &tcp_sendspace },		\
    858 	{ 1, 0, &tcp_recvspace },		\
    859 	{ 1, 0, &tcp_mssdflt },			\
    860 	{ 1, 0, &tcp_syn_cache_limit },		\
    861 	{ 1, 0, &tcp_syn_bucket_limit },	\
    862 	{ 0 },					\
    863 	{ 1, 0, &tcp_init_win },		\
    864 	{ 1, 0, &tcp_mss_ifmtu },		\
    865 	{ 1, 0, &tcp_do_sack },			\
    866 	{ 1, 0, &tcp_do_win_scale },		\
    867 	{ 1, 0, &tcp_do_timestamps },		\
    868 	{ 1, 0, &tcp_compat_42 },		\
    869 	{ 1, 0, &tcp_cwm },			\
    870 	{ 1, 0, &tcp_cwm_burstsize },		\
    871 	{ 1, 0, &tcp_ack_on_push },		\
    872 	{ 1, 0, &tcp_keepidle },		\
    873 	{ 1, 0, &tcp_keepintvl },		\
    874 	{ 1, 0, &tcp_keepcnt },			\
    875 	{ 1, 1, 0, PR_SLOWHZ },			\
    876 	{ 0 },					\
    877 	{ 1, 0, &tcp_log_refused },		\
    878 	{ 0 },					\
    879 	{ 1, 0, &tcp_rst_ppslim },		\
    880 	{ 1, 0, &tcp_delack_ticks },		\
    881 	{ 1, 0, &tcp_init_win_local },		\
    882 	{ 1, 0, &tcp_ackdrop_ppslim },		\
    883 }
    884 
    885 struct secasvar;
    886 
    887 int	 tcp_attach(struct socket *);
    888 void	 tcp_canceltimers(struct tcpcb *);
    889 struct tcpcb *
    890 	 tcp_close(struct tcpcb *);
    891 int	 tcp_isdead(struct tcpcb *);
    892 #ifdef INET6
    893 void	 *tcp6_ctlinput(int, const struct sockaddr *, void *);
    894 #endif
    895 void	 *tcp_ctlinput(int, const struct sockaddr *, void *);
    896 int	 tcp_ctloutput(int, struct socket *, struct sockopt *);
    897 struct tcpcb *
    898 	 tcp_disconnect(struct tcpcb *);
    899 struct tcpcb *
    900 	 tcp_drop(struct tcpcb *, int);
    901 #ifdef TCP_SIGNATURE
    902 int	 tcp_signature_apply(void *, void *, u_int);
    903 struct secasvar *tcp_signature_getsav(struct mbuf *, struct tcphdr *);
    904 int	 tcp_signature(struct mbuf *, struct tcphdr *, int, struct secasvar *,
    905 	    char *);
    906 #endif
    907 void	 tcp_drain(void);
    908 void	 tcp_drainstub(void);
    909 void	 tcp_established(struct tcpcb *);
    910 void	 tcp_init(void);
    911 #ifdef INET6
    912 int	 tcp6_input(struct mbuf **, int *, int);
    913 #endif
    914 void	 tcp_input(struct mbuf *, ...);
    915 u_int	 tcp_hdrsz(struct tcpcb *);
    916 u_long	 tcp_mss_to_advertise(const struct ifnet *, int);
    917 void	 tcp_mss_from_peer(struct tcpcb *, int);
    918 void	 tcp_tcpcb_template(void);
    919 struct tcpcb *
    920 	 tcp_newtcpcb(int, void *);
    921 void	 tcp_notify(struct inpcb *, int);
    922 #ifdef INET6
    923 void	 tcp6_notify(struct in6pcb *, int);
    924 #endif
    925 u_int	 tcp_optlen(struct tcpcb *);
    926 int	 tcp_output(struct tcpcb *);
    927 void	 tcp_pulloutofband(struct socket *,
    928 	    struct tcphdr *, struct mbuf *, int);
    929 void	 tcp_quench(struct inpcb *, int);
    930 #ifdef INET6
    931 void	 tcp6_quench(struct in6pcb *, int);
    932 #endif
    933 void	 tcp_mtudisc(struct inpcb *, int);
    934 
    935 void	tcpipqent_init(void);
    936 struct ipqent *tcpipqent_alloc(void);
    937 void	 tcpipqent_free(struct ipqent *);
    938 
    939 int	 tcp_respond(struct tcpcb *, struct mbuf *, struct mbuf *,
    940 	    struct tcphdr *, tcp_seq, tcp_seq, int);
    941 void	 tcp_rmx_rtt(struct tcpcb *);
    942 void	 tcp_setpersist(struct tcpcb *);
    943 #ifdef TCP_SIGNATURE
    944 int	 tcp_signature_compute(struct mbuf *, struct tcphdr *, int, int,
    945 	    int, u_char *, u_int);
    946 #endif
    947 void	 tcp_slowtimo(void);
    948 void	 tcp_fasttimo(void);
    949 struct mbuf *
    950 	 tcp_template(struct tcpcb *);
    951 void	 tcp_trace(short, short, struct tcpcb *, struct mbuf *, int);
    952 struct tcpcb *
    953 	 tcp_usrclosed(struct tcpcb *);
    954 void	 tcp_usrreq_init(void);
    955 int	 tcp_usrreq(struct socket *,
    956 	    int, struct mbuf *, struct mbuf *, struct mbuf *, struct lwp *);
    957 void	 tcp_xmit_timer(struct tcpcb *, uint32_t);
    958 tcp_seq	 tcp_new_iss(struct tcpcb *, tcp_seq);
    959 tcp_seq  tcp_new_iss1(void *, void *, u_int16_t, u_int16_t, size_t,
    960 	    tcp_seq);
    961 
    962 void	 tcp_sack_init(void);
    963 void	 tcp_new_dsack(struct tcpcb *, tcp_seq, u_int32_t);
    964 void	 tcp_sack_option(struct tcpcb *, const struct tcphdr *,
    965 	    const u_char *, int);
    966 void	 tcp_del_sackholes(struct tcpcb *, const struct tcphdr *);
    967 void	 tcp_free_sackholes(struct tcpcb *);
    968 void	 tcp_sack_adjust(struct tcpcb *tp);
    969 struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
    970 void	 tcp_sack_newack(struct tcpcb *, const struct tcphdr *);
    971 int	 tcp_sack_numblks(const struct tcpcb *);
    972 #define	TCP_SACK_OPTLEN(nblks)	((nblks) * 8 + 2 + 2)
    973 
    974 void	 tcp_statinc(u_int);
    975 void	 tcp_statadd(u_int, uint64_t);
    976 
    977 int	 syn_cache_add(struct sockaddr *, struct sockaddr *,
    978 		struct tcphdr *, unsigned int, struct socket *,
    979 		struct mbuf *, u_char *, int, struct tcp_opt_info *);
    980 void	 syn_cache_unreach(const struct sockaddr *, const struct sockaddr *,
    981 	   struct tcphdr *);
    982 struct socket *syn_cache_get(struct sockaddr *, struct sockaddr *,
    983 		struct tcphdr *, unsigned int, unsigned int,
    984 		struct socket *so, struct mbuf *);
    985 void	 syn_cache_init(void);
    986 void	 syn_cache_insert(struct syn_cache *, struct tcpcb *);
    987 struct syn_cache *syn_cache_lookup(const struct sockaddr *, const struct sockaddr *,
    988 		struct syn_cache_head **);
    989 void	 syn_cache_reset(struct sockaddr *, struct sockaddr *,
    990 		struct tcphdr *);
    991 int	 syn_cache_respond(struct syn_cache *, struct mbuf *);
    992 void	 syn_cache_timer(void *);
    993 void	 syn_cache_cleanup(struct tcpcb *);
    994 
    995 int	 tcp_input_checksum(int, struct mbuf *, const struct tcphdr *, int, int,
    996     int);
    997 #endif
    998 
    999 #endif /* !_NETINET_TCP_VAR_H_ */
   1000