xref: /dflybsd-src/sys/netinet/tcp_var.h (revision 1f2de5d41c9be614e9a1cba7cf16de309a2ea210)
1 /*
2  * Copyright (c) 1982, 1986, 1993, 1994, 1995
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
34  * $FreeBSD: src/sys/netinet/tcp_var.h,v 1.56.2.13 2003/02/03 02:34:07 hsu Exp $
35  * $DragonFly: src/sys/netinet/tcp_var.h,v 1.4 2003/07/24 01:31:07 dillon Exp $
36  */
37 
38 #ifndef _NETINET_TCP_VAR_H_
39 #define _NETINET_TCP_VAR_H_
40 
41 #include <netinet/in_pcb.h>		/* needed for in_conninfo, inp_gen_t */
42 
43 /*
44  * Kernel variables for tcp.
45  */
46 extern int	tcp_do_rfc1323;
47 extern int	tcp_do_rfc1644;
48 
49 /* TCP segment queue entry */
50 struct tseg_qent {
51 	LIST_ENTRY(tseg_qent) tqe_q;
52 	int	tqe_len;		/* TCP segment data length */
53 	struct	tcphdr *tqe_th;		/* a pointer to tcp header */
54 	struct	mbuf	*tqe_m;		/* mbuf contains packet */
55 };
56 LIST_HEAD(tsegqe_head, tseg_qent);
57 #ifdef MALLOC_DECLARE
58 MALLOC_DECLARE(M_TSEGQ);
59 #endif
60 
61 struct tcptemp {
62 	u_char	tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
63 	struct	tcphdr tt_t;
64 };
65 
66 #define tcp6cb		tcpcb  /* for KAME src sync over BSD*'s */
67 
68 /*
69  * Tcp control block, one per tcp; fields:
70  * Organized for 16 byte cacheline efficiency.
71  */
72 struct tcpcb {
73 	struct	tsegqe_head t_segq;
74 	int	t_dupacks;		/* consecutive dup acks recd */
75 	struct	tcptemp	*unused;	/* unused */
76 
77 	struct	callout *tt_rexmt;	/* retransmit timer */
78 	struct	callout *tt_persist;	/* retransmit persistence */
79 	struct	callout *tt_keep;	/* keepalive */
80 	struct	callout *tt_2msl;	/* 2*msl TIME_WAIT timer */
81 	struct	callout *tt_delack;	/* delayed ACK timer */
82 
83 	struct	inpcb *t_inpcb;		/* back pointer to internet pcb */
84 	int	t_state;		/* state of this connection */
85 	u_int	t_flags;
86 #define	TF_ACKNOW	0x000001	/* ack peer immediately */
87 #define	TF_DELACK	0x000002	/* ack, but try to delay it */
88 #define	TF_NODELAY	0x000004	/* don't delay packets to coalesce */
89 #define	TF_NOOPT	0x000008	/* don't use tcp options */
90 #define	TF_SENTFIN	0x000010	/* have sent FIN */
91 #define	TF_REQ_SCALE	0x000020	/* have/will request window scaling */
92 #define	TF_RCVD_SCALE	0x000040	/* other side has requested scaling */
93 #define	TF_REQ_TSTMP	0x000080	/* have/will request timestamps */
94 #define	TF_RCVD_TSTMP	0x000100	/* a timestamp was received in SYN */
95 #define	TF_SACK_PERMIT	0x000200	/* other side said I could SACK */
96 #define	TF_NEEDSYN	0x000400	/* send SYN (implicit state) */
97 #define	TF_NEEDFIN	0x000800	/* send FIN (implicit state) */
98 #define	TF_NOPUSH	0x001000	/* don't push */
99 #define	TF_REQ_CC	0x002000	/* have/will request CC */
100 #define	TF_RCVD_CC	0x004000	/* a CC was received in SYN */
101 #define	TF_SENDCCNEW	0x008000	/* send CCnew instead of CC in SYN */
102 #define	TF_MORETOCOME	0x010000	/* More data to be appended to sock */
103 #define	TF_LQ_OVERFLOW	0x020000	/* listen queue overflow */
104 #define	TF_LASTIDLE	0x040000	/* connection was previously idle */
105 #define	TF_RXWIN0SENT	0x080000	/* sent a receiver win 0 in response */
106 #define	TF_FASTRECOVERY	0x100000	/* in NewReno Fast Recovery */
107 #define	TF_WASFRECOVERY	0x200000	/* was in NewReno Fast Recovery */
108 	int	t_force;		/* 1 if forcing out a byte */
109 
110 	tcp_seq	snd_una;		/* send unacknowledged */
111 	tcp_seq	snd_max;		/* highest sequence number sent;
112 					 * used to recognize retransmits
113 					 */
114 	tcp_seq	snd_nxt;		/* send next */
115 	tcp_seq	snd_up;			/* send urgent pointer */
116 
117 	tcp_seq	snd_wl1;		/* window update seg seq number */
118 	tcp_seq	snd_wl2;		/* window update seg ack number */
119 	tcp_seq	iss;			/* initial send sequence number */
120 	tcp_seq	irs;			/* initial receive sequence number */
121 
122 	tcp_seq	rcv_nxt;		/* receive next */
123 	tcp_seq	rcv_adv;		/* advertised window */
124 	u_long	rcv_wnd;		/* receive window */
125 	tcp_seq	rcv_up;			/* receive urgent pointer */
126 
127 	u_long	snd_wnd;		/* send window */
128 	u_long	snd_cwnd;		/* congestion-controlled window */
129 	u_long	snd_bwnd;		/* bandwidth-controlled window */
130 	u_long	snd_ssthresh;		/* snd_cwnd size threshold for
131 					 * for slow start exponential to
132 					 * linear switch
133 					 */
134 	u_long	snd_bandwidth;		/* calculated bandwidth or 0 */
135 	tcp_seq	snd_recover;		/* for use in NewReno fast recovery */
136 
137 	u_int	t_maxopd;		/* mss plus options */
138 
139 	u_long	t_rcvtime;		/* inactivity time */
140 	u_long	t_starttime;		/* time connection was established */
141 	int	t_rtttime;		/* round trip time */
142 	tcp_seq	t_rtseq;		/* sequence number being timed */
143 
144 	int	t_bw_rtttime;		/* used for bandwidth calculation */
145 	tcp_seq	t_bw_rtseq;		/* used for bandwidth calculation */
146 
147 	int	t_rxtcur;		/* current retransmit value (ticks) */
148 	u_int	t_maxseg;		/* maximum segment size */
149 	int	t_srtt;			/* smoothed round-trip time */
150 	int	t_rttvar;		/* variance in round-trip time */
151 
152 	int	t_rxtshift;		/* log(2) of rexmt exp. backoff */
153 	u_int	t_rttmin;		/* minimum rtt allowed */
154 	u_int	t_rttbest;		/* best rtt we've seen */
155 	u_long	t_rttupdated;		/* number of times rtt sampled */
156 	u_long	max_sndwnd;		/* largest window peer has offered */
157 
158 	int	t_softerror;		/* possible error not yet reported */
159 /* out-of-band data */
160 	char	t_oobflags;		/* have some */
161 	char	t_iobc;			/* input character */
162 #define	TCPOOB_HAVEDATA	0x01
163 #define	TCPOOB_HADDATA	0x02
164 /* RFC 1323 variables */
165 	u_char	snd_scale;		/* window scaling for send window */
166 	u_char	rcv_scale;		/* window scaling for recv window */
167 	u_char	request_r_scale;	/* pending window scaling */
168 	u_char	requested_s_scale;
169 	u_long	ts_recent;		/* timestamp echo data */
170 
171 	u_long	ts_recent_age;		/* when last updated */
172 	tcp_seq	last_ack_sent;
173 /* RFC 1644 variables */
174 	tcp_cc	cc_send;		/* send connection count */
175 	tcp_cc	cc_recv;		/* receive connection count */
176 /* experimental */
177 	u_long	snd_cwnd_prev;		/* cwnd prior to retransmit */
178 	u_long	snd_ssthresh_prev;	/* ssthresh prior to retransmit */
179 	tcp_seq snd_recover_prev;	/* snd_recover prior to retransmit */
180 	u_long	t_badrxtwin;		/* window for retransmit recovery */
181 	u_char	snd_limited;		/* segments limited transmitted */
182 };
183 
184 #define	IN_FASTRECOVERY(tp)	(tp->t_flags & TF_FASTRECOVERY)
185 #define	ENTER_FASTRECOVERY(tp)	tp->t_flags |= TF_FASTRECOVERY
186 #define	EXIT_FASTRECOVERY(tp)	tp->t_flags &= ~TF_FASTRECOVERY
187 
188 /*
189  * Structure to hold TCP options that are only used during segment
190  * processing (in tcp_input), but not held in the tcpcb.
191  * It's basically used to reduce the number of parameters
192  * to tcp_dooptions.
193  */
194 struct tcpopt {
195 	u_long		to_flags;	/* which options are present */
196 #define TOF_TS		0x0001		/* timestamp */
197 #define TOF_CC		0x0002		/* CC and CCnew are exclusive */
198 #define TOF_CCNEW	0x0004
199 #define	TOF_CCECHO	0x0008
200 #define	TOF_MSS		0x0010
201 #define	TOF_SCALE	0x0020
202 	u_int32_t	to_tsval;
203 	u_int32_t	to_tsecr;
204 	tcp_cc		to_cc;		/* holds CC or CCnew */
205 	tcp_cc		to_ccecho;
206 	u_int16_t	to_mss;
207 	u_int8_t 	to_requested_s_scale;
208 	u_int8_t 	to_pad;
209 };
210 
211 struct syncache {
212 	inp_gen_t	sc_inp_gencnt;		/* pointer check */
213 	struct 		tcpcb *sc_tp;		/* tcb for listening socket */
214 	struct		mbuf *sc_ipopts;	/* source route */
215 	struct 		in_conninfo sc_inc;	/* addresses */
216 #define sc_route	sc_inc.inc_route
217 #define sc_route6	sc_inc.inc6_route
218 	u_int32_t	sc_tsrecent;
219 	tcp_cc		sc_cc_send;		/* holds CC or CCnew */
220 	tcp_cc		sc_cc_recv;
221 	tcp_seq 	sc_irs;			/* seq from peer */
222 	tcp_seq 	sc_iss;			/* our ISS */
223 	u_long		sc_rxttime;		/* retransmit time */
224 	u_int16_t	sc_rxtslot; 		/* retransmit counter */
225 	u_int16_t	sc_peer_mss;		/* peer's MSS */
226 	u_int16_t	sc_wnd;			/* advertised window */
227 	u_int8_t 	sc_requested_s_scale:4,
228 			sc_request_r_scale:4;
229 	u_int8_t	sc_flags;
230 #define SCF_NOOPT	0x01			/* no TCP options */
231 #define SCF_WINSCALE	0x02			/* negotiated window scaling */
232 #define SCF_TIMESTAMP	0x04			/* negotiated timestamps */
233 #define SCF_CC		0x08			/* negotiated CC */
234 #define SCF_UNREACH	0x10			/* icmp unreachable received */
235 #define SCF_KEEPROUTE	0x20			/* keep cloned route */
236 	TAILQ_ENTRY(syncache)	sc_hash;
237 	TAILQ_ENTRY(syncache)	sc_timerq;
238 };
239 
240 struct syncache_head {
241 	TAILQ_HEAD(, syncache)	sch_bucket;
242 	u_int		sch_length;
243 };
244 
245 /*
246  * The TAO cache entry which is stored in the protocol family specific
247  * portion of the route metrics.
248  */
249 struct rmxp_tao {
250 	tcp_cc	tao_cc;			/* latest CC in valid SYN */
251 	tcp_cc	tao_ccsent;		/* latest CC sent to peer */
252 	u_short	tao_mssopt;		/* peer's cached MSS */
253 #ifdef notyet
254 	u_short	tao_flags;		/* cache status flags */
255 #define	TAOF_DONT	0x0001		/* peer doesn't understand rfc1644 */
256 #define	TAOF_OK		0x0002		/* peer does understand rfc1644 */
257 #define	TAOF_UNDEF	0		/* we don't know yet */
258 #endif /* notyet */
259 };
260 #define rmx_taop(r)	((struct rmxp_tao *)(r).rmx_filler)
261 
262 #define	intotcpcb(ip)	((struct tcpcb *)(ip)->inp_ppcb)
263 #define	sototcpcb(so)	(intotcpcb(sotoinpcb(so)))
264 
265 /*
266  * The smoothed round-trip time and estimated variance
267  * are stored as fixed point numbers scaled by the values below.
268  * For convenience, these scales are also used in smoothing the average
269  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
270  * With these scales, srtt has 3 bits to the right of the binary point,
271  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
272  * binary point, and is smoothed with an ALPHA of 0.75.
273  */
274 #define	TCP_RTT_SCALE		32	/* multiplier for srtt; 3 bits frac. */
275 #define	TCP_RTT_SHIFT		5	/* shift for srtt; 3 bits frac. */
276 #define	TCP_RTTVAR_SCALE	16	/* multiplier for rttvar; 2 bits */
277 #define	TCP_RTTVAR_SHIFT	4	/* shift for rttvar; 2 bits */
278 #define	TCP_DELTA_SHIFT		2	/* see tcp_input.c */
279 
280 /*
281  * The initial retransmission should happen at rtt + 4 * rttvar.
282  * Because of the way we do the smoothing, srtt and rttvar
283  * will each average +1/2 tick of bias.  When we compute
284  * the retransmit timer, we want 1/2 tick of rounding and
285  * 1 extra tick because of +-1/2 tick uncertainty in the
286  * firing of the timer.  The bias will give us exactly the
287  * 1.5 tick we need.  But, because the bias is
288  * statistical, we have to test that we don't drop below
289  * the minimum feasible timer (which is 2 ticks).
290  * This version of the macro adapted from a paper by Lawrence
291  * Brakmo and Larry Peterson which outlines a problem caused
292  * by insufficient precision in the original implementation,
293  * which results in inappropriately large RTO values for very
294  * fast networks.
295  */
296 #define	TCP_REXMTVAL(tp) \
297 	max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
298 	  + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
299 
300 /*
301  * TCP statistics.
302  * Many of these should be kept per connection,
303  * but that's inconvenient at the moment.
304  */
305 struct	tcpstat {
306 	u_long	tcps_connattempt;	/* connections initiated */
307 	u_long	tcps_accepts;		/* connections accepted */
308 	u_long	tcps_connects;		/* connections established */
309 	u_long	tcps_drops;		/* connections dropped */
310 	u_long	tcps_conndrops;		/* embryonic connections dropped */
311 	u_long	tcps_closed;		/* conn. closed (includes drops) */
312 	u_long	tcps_segstimed;		/* segs where we tried to get rtt */
313 	u_long	tcps_rttupdated;	/* times we succeeded */
314 	u_long	tcps_delack;		/* delayed acks sent */
315 	u_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */
316 	u_long	tcps_rexmttimeo;	/* retransmit timeouts */
317 	u_long	tcps_persisttimeo;	/* persist timeouts */
318 	u_long	tcps_keeptimeo;		/* keepalive timeouts */
319 	u_long	tcps_keepprobe;		/* keepalive probes sent */
320 	u_long	tcps_keepdrops;		/* connections dropped in keepalive */
321 
322 	u_long	tcps_sndtotal;		/* total packets sent */
323 	u_long	tcps_sndpack;		/* data packets sent */
324 	u_long	tcps_sndbyte;		/* data bytes sent */
325 	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
326 	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
327 	u_long	tcps_sndacks;		/* ack-only packets sent */
328 	u_long	tcps_sndprobe;		/* window probes sent */
329 	u_long	tcps_sndurg;		/* packets sent with URG only */
330 	u_long	tcps_sndwinup;		/* window update-only packets sent */
331 	u_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */
332 
333 	u_long	tcps_rcvtotal;		/* total packets received */
334 	u_long	tcps_rcvpack;		/* packets received in sequence */
335 	u_long	tcps_rcvbyte;		/* bytes received in sequence */
336 	u_long	tcps_rcvbadsum;		/* packets received with ccksum errs */
337 	u_long	tcps_rcvbadoff;		/* packets received with bad offset */
338 	u_long	tcps_rcvmemdrop;	/* packets dropped for lack of memory */
339 	u_long	tcps_rcvshort;		/* packets received too short */
340 	u_long	tcps_rcvduppack;	/* duplicate-only packets received */
341 	u_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */
342 	u_long	tcps_rcvpartduppack;	/* packets with some duplicate data */
343 	u_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */
344 	u_long	tcps_rcvoopack;		/* out-of-order packets received */
345 	u_long	tcps_rcvoobyte;		/* out-of-order bytes received */
346 	u_long	tcps_rcvpackafterwin;	/* packets with data after window */
347 	u_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */
348 	u_long	tcps_rcvafterclose;	/* packets rcvd after "close" */
349 	u_long	tcps_rcvwinprobe;	/* rcvd window probe packets */
350 	u_long	tcps_rcvdupack;		/* rcvd duplicate acks */
351 	u_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */
352 	u_long	tcps_rcvackpack;	/* rcvd ack packets */
353 	u_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */
354 	u_long	tcps_rcvwinupd;		/* rcvd window update packets */
355 	u_long	tcps_pawsdrop;		/* segments dropped due to PAWS */
356 	u_long	tcps_predack;		/* times hdr predict ok for acks */
357 	u_long	tcps_preddat;		/* times hdr predict ok for data pkts */
358 	u_long	tcps_pcbcachemiss;
359 	u_long	tcps_cachedrtt;		/* times cached RTT in route updated */
360 	u_long	tcps_cachedrttvar;	/* times cached rttvar updated */
361 	u_long	tcps_cachedssthresh;	/* times cached ssthresh updated */
362 	u_long	tcps_usedrtt;		/* times RTT initialized from route */
363 	u_long	tcps_usedrttvar;	/* times RTTVAR initialized from rt */
364 	u_long	tcps_usedssthresh;	/* times ssthresh initialized from rt*/
365 	u_long	tcps_persistdrop;	/* timeout in persist state */
366 	u_long	tcps_badsyn;		/* bogus SYN, e.g. premature ACK */
367 	u_long	tcps_mturesent;		/* resends due to MTU discovery */
368 	u_long	tcps_listendrop;	/* listen queue overflows */
369 
370 	u_long	tcps_sc_added;		/* entry added to syncache */
371 	u_long	tcps_sc_retransmitted;	/* syncache entry was retransmitted */
372 	u_long	tcps_sc_dupsyn;		/* duplicate SYN packet */
373 	u_long	tcps_sc_dropped;	/* could not reply to packet */
374 	u_long	tcps_sc_completed;	/* successful extraction of entry */
375 	u_long	tcps_sc_bucketoverflow;	/* syncache per-bucket limit hit */
376 	u_long	tcps_sc_cacheoverflow;	/* syncache cache limit hit */
377 	u_long	tcps_sc_reset;		/* RST removed entry from syncache */
378 	u_long	tcps_sc_stale;		/* timed out or listen socket gone */
379 	u_long	tcps_sc_aborted;	/* syncache entry aborted */
380 	u_long	tcps_sc_badack;		/* removed due to bad ACK */
381 	u_long	tcps_sc_unreach;	/* ICMP unreachable received */
382 	u_long	tcps_sc_zonefail;	/* zalloc() failed */
383 	u_long	tcps_sc_sendcookie;	/* SYN cookie sent */
384 	u_long	tcps_sc_recvcookie;	/* SYN cookie received */
385 };
386 
387 /*
388  * TCB structure exported to user-land via sysctl(3).
389  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
390  * included.  Not all of our clients do.
391  */
392 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
393 struct	xtcpcb {
394 	size_t	xt_len;
395 	struct	inpcb	xt_inp;
396 	struct	tcpcb	xt_tp;
397 	struct	xsocket	xt_socket;
398 	u_quad_t	xt_alignment_hack;
399 };
400 #endif
401 
402 /*
403  * Names for TCP sysctl objects
404  */
405 #define	TCPCTL_DO_RFC1323	1	/* use RFC-1323 extensions */
406 #define	TCPCTL_DO_RFC1644	2	/* use RFC-1644 extensions */
407 #define	TCPCTL_MSSDFLT		3	/* MSS default */
408 #define TCPCTL_STATS		4	/* statistics (read-only) */
409 #define	TCPCTL_RTTDFLT		5	/* default RTT estimate */
410 #define	TCPCTL_KEEPIDLE		6	/* keepalive idle timer */
411 #define	TCPCTL_KEEPINTVL	7	/* interval to send keepalives */
412 #define	TCPCTL_SENDSPACE	8	/* send buffer space */
413 #define	TCPCTL_RECVSPACE	9	/* receive buffer space */
414 #define	TCPCTL_KEEPINIT		10	/* timeout for establishing syn */
415 #define	TCPCTL_PCBLIST		11	/* list of all outstanding PCBs */
416 #define	TCPCTL_DELACKTIME	12	/* time before sending delayed ACK */
417 #define	TCPCTL_V6MSSDFLT	13	/* MSS default for IPv6 */
418 #define	TCPCTL_MAXID		14
419 
420 #define TCPCTL_NAMES { \
421 	{ 0, 0 }, \
422 	{ "rfc1323", CTLTYPE_INT }, \
423 	{ "rfc1644", CTLTYPE_INT }, \
424 	{ "mssdflt", CTLTYPE_INT }, \
425 	{ "stats", CTLTYPE_STRUCT }, \
426 	{ "rttdflt", CTLTYPE_INT }, \
427 	{ "keepidle", CTLTYPE_INT }, \
428 	{ "keepintvl", CTLTYPE_INT }, \
429 	{ "sendspace", CTLTYPE_INT }, \
430 	{ "recvspace", CTLTYPE_INT }, \
431 	{ "keepinit", CTLTYPE_INT }, \
432 	{ "pcblist", CTLTYPE_STRUCT }, \
433 	{ "delacktime", CTLTYPE_INT }, \
434 	{ "v6mssdflt", CTLTYPE_INT }, \
435 }
436 
437 
438 #ifdef _KERNEL
439 #ifdef SYSCTL_DECL
440 SYSCTL_DECL(_net_inet_tcp);
441 #endif
442 
443 extern	struct inpcbhead tcb;		/* head of queue of active tcpcb's */
444 extern	struct inpcbinfo tcbinfo;
445 extern	struct tcpstat tcpstat;	/* tcp statistics */
446 extern	int tcp_mssdflt;	/* XXX */
447 extern	int tcp_delack_enabled;
448 extern	int tcp_do_newreno;
449 extern	int path_mtu_discovery;
450 extern	int ss_fltsz;
451 extern	int ss_fltsz_local;
452 
453 void	 tcp_canceltimers __P((struct tcpcb *));
454 struct tcpcb *
455 	 tcp_close __P((struct tcpcb *));
456 void	 tcp_ctlinput __P((int, struct sockaddr *, void *));
457 int	 tcp_ctloutput __P((struct socket *, struct sockopt *));
458 struct tcpcb *
459 	 tcp_drop __P((struct tcpcb *, int));
460 void	 tcp_drain __P((void));
461 void	 tcp_fasttimo __P((void));
462 struct rmxp_tao *
463 	 tcp_gettaocache __P((struct in_conninfo *));
464 void	 tcp_init __P((void));
465 void	 tcp_input __P((struct mbuf *, int, int));
466 void	 tcp_mss __P((struct tcpcb *, int));
467 int	 tcp_mssopt __P((struct tcpcb *));
468 void	 tcp_drop_syn_sent __P((struct inpcb *, int));
469 void	 tcp_mtudisc __P((struct inpcb *, int));
470 struct tcpcb *
471 	 tcp_newtcpcb __P((struct inpcb *));
472 int	 tcp_output __P((struct tcpcb *));
473 void	 tcp_quench __P((struct inpcb *, int));
474 void	 tcp_respond __P((struct tcpcb *, void *,
475 	    struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int));
476 struct rtentry *
477 	 tcp_rtlookup __P((struct in_conninfo *));
478 void	 tcp_setpersist __P((struct tcpcb *));
479 void	 tcp_slowtimo __P((void));
480 struct tcptemp *
481 	 tcp_maketemplate __P((struct tcpcb *));
482 void	 tcp_fillheaders __P((struct tcpcb *, void *, void *));
483 struct tcpcb *
484 	 tcp_timers __P((struct tcpcb *, int));
485 void	 tcp_trace __P((int, int, struct tcpcb *, void *, struct tcphdr *,
486 			int));
487 void	 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
488 void	 syncache_init(void);
489 void	 syncache_unreach(struct in_conninfo *, struct tcphdr *);
490 int	 syncache_expand(struct in_conninfo *, struct tcphdr *,
491 	     struct socket **, struct mbuf *);
492 int	 syncache_add(struct in_conninfo *, struct tcpopt *,
493 	     struct tcphdr *, struct socket **, struct mbuf *);
494 void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *);
495 void	 syncache_badack(struct in_conninfo *);
496 
497 extern	struct pr_usrreqs tcp_usrreqs;
498 extern	u_long tcp_sendspace;
499 extern	u_long tcp_recvspace;
500 tcp_seq tcp_new_isn __P((struct tcpcb *));
501 
502 #endif /* _KERNEL */
503 
504 #endif /* _NETINET_TCP_VAR_H_ */
505