xref: /freebsd/sys/netinet/tcp_var.h (revision 729362425c09cf6b362366aabc6fb547eee8035a)
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  * $FreeBSD$
35  */
36 
37 #ifndef _NETINET_TCP_VAR_H_
38 #define _NETINET_TCP_VAR_H_
39 
40 #include <netinet/in_pcb.h>		/* needed for in_conninfo, inp_gen_t */
41 #include <netinet/tcp.h>
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	0x00001		/* ack peer immediately */
87 #define	TF_DELACK	0x00002		/* ack, but try to delay it */
88 #define	TF_NODELAY	0x00004		/* don't delay packets to coalesce */
89 #define	TF_NOOPT	0x00008		/* don't use tcp options */
90 #define	TF_SENTFIN	0x00010		/* have sent FIN */
91 #define	TF_REQ_SCALE	0x00020		/* have/will request window scaling */
92 #define	TF_RCVD_SCALE	0x00040		/* other side has requested scaling */
93 #define	TF_REQ_TSTMP	0x00080		/* have/will request timestamps */
94 #define	TF_RCVD_TSTMP	0x00100		/* a timestamp was received in SYN */
95 #define	TF_SACK_PERMIT	0x00200		/* other side said I could SACK */
96 #define	TF_NEEDSYN	0x00400		/* send SYN (implicit state) */
97 #define	TF_NEEDFIN	0x00800		/* send FIN (implicit state) */
98 #define	TF_NOPUSH	0x01000		/* don't push */
99 #define	TF_REQ_CC	0x02000		/* have/will request CC */
100 #define	TF_RCVD_CC	0x04000		/* a CC was received in SYN */
101 #define	TF_SENDCCNEW	0x08000		/* send CCnew instead of CC in SYN */
102 #define	TF_MORETOCOME	0x10000		/* More data to be appended to sock */
103 #define	TF_LQ_OVERFLOW	0x20000		/* listen queue overflow */
104 #define	TF_LASTIDLE	0x40000		/* connection was previously idle */
105 #define TF_RXWIN0SENT	0x80000		/* sent a receiver win 0 in response */
106 	int	t_force;		/* 1 if forcing out a byte */
107 
108 	tcp_seq	snd_una;		/* send unacknowledged */
109 	tcp_seq	snd_max;		/* highest sequence number sent;
110 					 * used to recognize retransmits
111 					 */
112 	tcp_seq	snd_nxt;		/* send next */
113 	tcp_seq	snd_up;			/* send urgent pointer */
114 
115 	tcp_seq	snd_wl1;		/* window update seg seq number */
116 	tcp_seq	snd_wl2;		/* window update seg ack number */
117 	tcp_seq	iss;			/* initial send sequence number */
118 	tcp_seq	irs;			/* initial receive sequence number */
119 
120 	tcp_seq	rcv_nxt;		/* receive next */
121 	tcp_seq	rcv_adv;		/* advertised window */
122 	u_long	rcv_wnd;		/* receive window */
123 	tcp_seq	rcv_up;			/* receive urgent pointer */
124 
125 	u_long	snd_wnd;		/* send window */
126 	u_long	snd_cwnd;		/* congestion-controlled window */
127 	u_long	snd_bwnd;		/* bandwidth-controlled window */
128 	u_long	snd_ssthresh;		/* snd_cwnd size threshold for
129 					 * for slow start exponential to
130 					 * linear switch
131 					 */
132 	u_long	snd_bandwidth;		/* calculated bandwidth or 0 */
133 	tcp_seq	snd_recover;		/* for use in NewReno Fast Recovery */
134 	tcp_seq snd_high;		/* for use in NewReno Fast Recovery */
135 
136 	u_int	t_maxopd;		/* mss plus options */
137 
138 	u_long	t_rcvtime;		/* inactivity time */
139 	u_long	t_starttime;		/* time connection was established */
140 	int	t_rtttime;		/* round trip time */
141 	tcp_seq	t_rtseq;		/* sequence number being timed */
142 
143 	int	t_bw_rtttime;		/* used for bandwidth calculation */
144 	tcp_seq	t_bw_rtseq;		/* used for bandwidth calculation */
145 
146 	int	t_rxtcur;		/* current retransmit value (ticks) */
147 	u_int	t_maxseg;		/* maximum segment size */
148 	int	t_srtt;			/* smoothed round-trip time */
149 	int	t_rttvar;		/* variance in round-trip time */
150 
151 	int	t_rxtshift;		/* log(2) of rexmt exp. backoff */
152 	u_int	t_rttmin;		/* minimum rtt allowed */
153 	u_int	t_rttbest;		/* best rtt we've seen */
154 	u_long	t_rttupdated;		/* number of times rtt sampled */
155 	u_long	max_sndwnd;		/* largest window peer has offered */
156 
157 	int	t_softerror;		/* possible error not yet reported */
158 /* out-of-band data */
159 	char	t_oobflags;		/* have some */
160 	char	t_iobc;			/* input character */
161 #define	TCPOOB_HAVEDATA	0x01
162 #define	TCPOOB_HADDATA	0x02
163 /* RFC 1323 variables */
164 	u_char	snd_scale;		/* window scaling for send window */
165 	u_char	rcv_scale;		/* window scaling for recv window */
166 	u_char	request_r_scale;	/* pending window scaling */
167 	u_char	requested_s_scale;
168 	u_long	ts_recent;		/* timestamp echo data */
169 
170 	u_long	ts_recent_age;		/* when last updated */
171 	tcp_seq	last_ack_sent;
172 /* RFC 1644 variables */
173 	tcp_cc	cc_send;		/* send connection count */
174 	tcp_cc	cc_recv;		/* receive connection count */
175 /* experimental */
176 	u_long	snd_cwnd_prev;		/* cwnd prior to retransmit */
177 	u_long	snd_ssthresh_prev;	/* ssthresh prior to retransmit */
178 	tcp_seq	snd_high_prev;		/* snd_high prior to retransmit */
179 	u_long	t_badrxtwin;		/* window for retransmit recovery */
180 };
181 
182 /*
183  * Structure to hold TCP options that are only used during segment
184  * processing (in tcp_input), but not held in the tcpcb.
185  * It's basically used to reduce the number of parameters
186  * to tcp_dooptions.
187  */
188 struct tcpopt {
189 	u_long		to_flags;	/* which options are present */
190 #define TOF_TS		0x0001		/* timestamp */
191 #define TOF_CC		0x0002		/* CC and CCnew are exclusive */
192 #define TOF_CCNEW	0x0004
193 #define	TOF_CCECHO	0x0008
194 #define	TOF_MSS		0x0010
195 #define	TOF_SCALE	0x0020
196 	u_int32_t	to_tsval;
197 	u_int32_t	to_tsecr;
198 	tcp_cc		to_cc;		/* holds CC or CCnew */
199 	tcp_cc		to_ccecho;
200 	u_int16_t	to_mss;
201 	u_int8_t 	to_requested_s_scale;
202 	u_int8_t 	to_pad;
203 };
204 
205 struct syncache {
206 	inp_gen_t	sc_inp_gencnt;		/* pointer check */
207 	struct 		tcpcb *sc_tp;		/* tcb for listening socket */
208 	struct		mbuf *sc_ipopts;	/* source route */
209 	struct 		in_conninfo sc_inc;	/* addresses */
210 #define sc_route	sc_inc.inc_route
211 #define sc_route6	sc_inc.inc6_route
212 	u_int32_t	sc_tsrecent;
213 	tcp_cc		sc_cc_send;		/* holds CC or CCnew */
214 	tcp_cc		sc_cc_recv;
215 	tcp_seq 	sc_irs;			/* seq from peer */
216 	tcp_seq 	sc_iss;			/* our ISS */
217 	u_long		sc_rxttime;		/* retransmit time */
218 	u_int16_t	sc_rxtslot; 		/* retransmit counter */
219 	u_int16_t	sc_peer_mss;		/* peer's MSS */
220 	u_int16_t	sc_wnd;			/* advertised window */
221 	u_int8_t 	sc_requested_s_scale:4,
222 			sc_request_r_scale:4;
223 	u_int8_t	sc_flags;
224 #define SCF_NOOPT	0x01			/* no TCP options */
225 #define SCF_WINSCALE	0x02			/* negotiated window scaling */
226 #define SCF_TIMESTAMP	0x04			/* negotiated timestamps */
227 #define SCF_CC		0x08			/* negotiated CC */
228 #define SCF_UNREACH	0x10			/* icmp unreachable received */
229 #define SCF_KEEPROUTE	0x20			/* keep cloned route */
230 	TAILQ_ENTRY(syncache)	sc_hash;
231 	TAILQ_ENTRY(syncache)	sc_timerq;
232 };
233 
234 struct syncache_head {
235 	TAILQ_HEAD(, syncache)	sch_bucket;
236 	u_int		sch_length;
237 };
238 
239 struct tcptw {
240 	struct inpcb	*tw_inpcb;	/* XXX back pointer to internet pcb */
241 	tcp_seq		snd_nxt;
242 	tcp_seq		rcv_nxt;
243 	tcp_cc		cc_recv;
244 	tcp_cc		cc_send;
245 	u_short		last_win;	/* cached window value */
246 	u_short		tw_so_options;	/* copy of so_options */
247 	struct ucred	*tw_cred;	/* user credentials */
248 	u_long 		t_recent;
249 	u_long		t_starttime;
250 	int		tw_time;
251 	LIST_ENTRY(tcptw) tw_2msl;
252 };
253 
254 /*
255  * The TAO cache entry which is stored in the protocol family specific
256  * portion of the route metrics.
257  */
258 struct rmxp_tao {
259 	tcp_cc	tao_cc;			/* latest CC in valid SYN */
260 	tcp_cc	tao_ccsent;		/* latest CC sent to peer */
261 	u_short	tao_mssopt;		/* peer's cached MSS */
262 #ifdef notyet
263 	u_short	tao_flags;		/* cache status flags */
264 #define	TAOF_DONT	0x0001		/* peer doesn't understand rfc1644 */
265 #define	TAOF_OK		0x0002		/* peer does understand rfc1644 */
266 #define	TAOF_UNDEF	0		/* we don't know yet */
267 #endif /* notyet */
268 };
269 #define rmx_taop(r)	((struct rmxp_tao *)(r).rmx_filler)
270 
271 #define	intotcpcb(ip)	((struct tcpcb *)(ip)->inp_ppcb)
272 #define	intotw(ip)	((struct tcptw *)(ip)->inp_ppcb)
273 #define	sototcpcb(so)	(intotcpcb(sotoinpcb(so)))
274 
275 /*
276  * The smoothed round-trip time and estimated variance
277  * are stored as fixed point numbers scaled by the values below.
278  * For convenience, these scales are also used in smoothing the average
279  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
280  * With these scales, srtt has 3 bits to the right of the binary point,
281  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
282  * binary point, and is smoothed with an ALPHA of 0.75.
283  */
284 #define	TCP_RTT_SCALE		32	/* multiplier for srtt; 3 bits frac. */
285 #define	TCP_RTT_SHIFT		5	/* shift for srtt; 3 bits frac. */
286 #define	TCP_RTTVAR_SCALE	16	/* multiplier for rttvar; 2 bits */
287 #define	TCP_RTTVAR_SHIFT	4	/* shift for rttvar; 2 bits */
288 #define	TCP_DELTA_SHIFT		2	/* see tcp_input.c */
289 
290 /*
291  * The initial retransmission should happen at rtt + 4 * rttvar.
292  * Because of the way we do the smoothing, srtt and rttvar
293  * will each average +1/2 tick of bias.  When we compute
294  * the retransmit timer, we want 1/2 tick of rounding and
295  * 1 extra tick because of +-1/2 tick uncertainty in the
296  * firing of the timer.  The bias will give us exactly the
297  * 1.5 tick we need.  But, because the bias is
298  * statistical, we have to test that we don't drop below
299  * the minimum feasible timer (which is 2 ticks).
300  * This version of the macro adapted from a paper by Lawrence
301  * Brakmo and Larry Peterson which outlines a problem caused
302  * by insufficient precision in the original implementation,
303  * which results in inappropriately large RTO values for very
304  * fast networks.
305  */
306 #define	TCP_REXMTVAL(tp) \
307 	max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
308 	  + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
309 
310 /*
311  * TCP statistics.
312  * Many of these should be kept per connection,
313  * but that's inconvenient at the moment.
314  */
315 struct	tcpstat {
316 	u_long	tcps_connattempt;	/* connections initiated */
317 	u_long	tcps_accepts;		/* connections accepted */
318 	u_long	tcps_connects;		/* connections established */
319 	u_long	tcps_drops;		/* connections dropped */
320 	u_long	tcps_conndrops;		/* embryonic connections dropped */
321 	u_long	tcps_closed;		/* conn. closed (includes drops) */
322 	u_long	tcps_segstimed;		/* segs where we tried to get rtt */
323 	u_long	tcps_rttupdated;	/* times we succeeded */
324 	u_long	tcps_delack;		/* delayed acks sent */
325 	u_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */
326 	u_long	tcps_rexmttimeo;	/* retransmit timeouts */
327 	u_long	tcps_persisttimeo;	/* persist timeouts */
328 	u_long	tcps_keeptimeo;		/* keepalive timeouts */
329 	u_long	tcps_keepprobe;		/* keepalive probes sent */
330 	u_long	tcps_keepdrops;		/* connections dropped in keepalive */
331 
332 	u_long	tcps_sndtotal;		/* total packets sent */
333 	u_long	tcps_sndpack;		/* data packets sent */
334 	u_long	tcps_sndbyte;		/* data bytes sent */
335 	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
336 	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
337 	u_long	tcps_sndrexmitbad;	/* unnecessary packet retransmissions */
338 	u_long	tcps_sndacks;		/* ack-only packets sent */
339 	u_long	tcps_sndprobe;		/* window probes sent */
340 	u_long	tcps_sndurg;		/* packets sent with URG only */
341 	u_long	tcps_sndwinup;		/* window update-only packets sent */
342 	u_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */
343 
344 	u_long	tcps_rcvtotal;		/* total packets received */
345 	u_long	tcps_rcvpack;		/* packets received in sequence */
346 	u_long	tcps_rcvbyte;		/* bytes received in sequence */
347 	u_long	tcps_rcvbadsum;		/* packets received with ccksum errs */
348 	u_long	tcps_rcvbadoff;		/* packets received with bad offset */
349 	u_long	tcps_rcvmemdrop;	/* packets dropped for lack of memory */
350 	u_long	tcps_rcvshort;		/* packets received too short */
351 	u_long	tcps_rcvduppack;	/* duplicate-only packets received */
352 	u_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */
353 	u_long	tcps_rcvpartduppack;	/* packets with some duplicate data */
354 	u_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */
355 	u_long	tcps_rcvoopack;		/* out-of-order packets received */
356 	u_long	tcps_rcvoobyte;		/* out-of-order bytes received */
357 	u_long	tcps_rcvpackafterwin;	/* packets with data after window */
358 	u_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */
359 	u_long	tcps_rcvafterclose;	/* packets rcvd after "close" */
360 	u_long	tcps_rcvwinprobe;	/* rcvd window probe packets */
361 	u_long	tcps_rcvdupack;		/* rcvd duplicate acks */
362 	u_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */
363 	u_long	tcps_rcvackpack;	/* rcvd ack packets */
364 	u_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */
365 	u_long	tcps_rcvwinupd;		/* rcvd window update packets */
366 	u_long	tcps_pawsdrop;		/* segments dropped due to PAWS */
367 	u_long	tcps_predack;		/* times hdr predict ok for acks */
368 	u_long	tcps_preddat;		/* times hdr predict ok for data pkts */
369 	u_long	tcps_pcbcachemiss;
370 	u_long	tcps_cachedrtt;		/* times cached RTT in route updated */
371 	u_long	tcps_cachedrttvar;	/* times cached rttvar updated */
372 	u_long	tcps_cachedssthresh;	/* times cached ssthresh updated */
373 	u_long	tcps_usedrtt;		/* times RTT initialized from route */
374 	u_long	tcps_usedrttvar;	/* times RTTVAR initialized from rt */
375 	u_long	tcps_usedssthresh;	/* times ssthresh initialized from rt*/
376 	u_long	tcps_persistdrop;	/* timeout in persist state */
377 	u_long	tcps_badsyn;		/* bogus SYN, e.g. premature ACK */
378 	u_long	tcps_mturesent;		/* resends due to MTU discovery */
379 	u_long	tcps_listendrop;	/* listen queue overflows */
380 
381 	u_long	tcps_sc_added;		/* entry added to syncache */
382 	u_long	tcps_sc_retransmitted;	/* syncache entry was retransmitted */
383 	u_long	tcps_sc_dupsyn;		/* duplicate SYN packet */
384 	u_long	tcps_sc_dropped;	/* could not reply to packet */
385 	u_long	tcps_sc_completed;	/* successful extraction of entry */
386 	u_long	tcps_sc_bucketoverflow;	/* syncache per-bucket limit hit */
387 	u_long	tcps_sc_cacheoverflow;	/* syncache cache limit hit */
388 	u_long	tcps_sc_reset;		/* RST removed entry from syncache */
389 	u_long	tcps_sc_stale;		/* timed out or listen socket gone */
390 	u_long	tcps_sc_aborted;	/* syncache entry aborted */
391 	u_long	tcps_sc_badack;		/* removed due to bad ACK */
392 	u_long	tcps_sc_unreach;	/* ICMP unreachable received */
393 	u_long	tcps_sc_zonefail;	/* zalloc() failed */
394 	u_long	tcps_sc_sendcookie;	/* SYN cookie sent */
395 	u_long	tcps_sc_recvcookie;	/* SYN cookie received */
396 };
397 
398 /*
399  * TCB structure exported to user-land via sysctl(3).
400  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
401  * included.  Not all of our clients do.
402  */
403 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
404 struct	xtcpcb {
405 	size_t	xt_len;
406 	struct	inpcb	xt_inp;
407 	struct	tcpcb	xt_tp;
408 	struct	xsocket	xt_socket;
409 	u_quad_t	xt_alignment_hack;
410 };
411 #endif
412 
413 /*
414  * Names for TCP sysctl objects
415  */
416 #define	TCPCTL_DO_RFC1323	1	/* use RFC-1323 extensions */
417 #define	TCPCTL_DO_RFC1644	2	/* use RFC-1644 extensions */
418 #define	TCPCTL_MSSDFLT		3	/* MSS default */
419 #define TCPCTL_STATS		4	/* statistics (read-only) */
420 #define	TCPCTL_RTTDFLT		5	/* default RTT estimate */
421 #define	TCPCTL_KEEPIDLE		6	/* keepalive idle timer */
422 #define	TCPCTL_KEEPINTVL	7	/* interval to send keepalives */
423 #define	TCPCTL_SENDSPACE	8	/* send buffer space */
424 #define	TCPCTL_RECVSPACE	9	/* receive buffer space */
425 #define	TCPCTL_KEEPINIT		10	/* timeout for establishing syn */
426 #define	TCPCTL_PCBLIST		11	/* list of all outstanding PCBs */
427 #define	TCPCTL_DELACKTIME	12	/* time before sending delayed ACK */
428 #define	TCPCTL_V6MSSDFLT	13	/* MSS default for IPv6 */
429 #define	TCPCTL_MAXID		14
430 
431 #define TCPCTL_NAMES { \
432 	{ 0, 0 }, \
433 	{ "rfc1323", CTLTYPE_INT }, \
434 	{ "rfc1644", CTLTYPE_INT }, \
435 	{ "mssdflt", CTLTYPE_INT }, \
436 	{ "stats", CTLTYPE_STRUCT }, \
437 	{ "rttdflt", CTLTYPE_INT }, \
438 	{ "keepidle", CTLTYPE_INT }, \
439 	{ "keepintvl", CTLTYPE_INT }, \
440 	{ "sendspace", CTLTYPE_INT }, \
441 	{ "recvspace", CTLTYPE_INT }, \
442 	{ "keepinit", CTLTYPE_INT }, \
443 	{ "pcblist", CTLTYPE_STRUCT }, \
444 	{ "delacktime", CTLTYPE_INT }, \
445 	{ "v6mssdflt", CTLTYPE_INT }, \
446 }
447 
448 
449 #ifdef _KERNEL
450 #ifdef SYSCTL_DECL
451 SYSCTL_DECL(_net_inet_tcp);
452 #endif
453 
454 extern	struct inpcbhead tcb;		/* head of queue of active tcpcb's */
455 extern	struct inpcbinfo tcbinfo;
456 extern	struct tcpstat tcpstat;	/* tcp statistics */
457 extern	int tcp_mssdflt;	/* XXX */
458 extern	int tcp_delack_enabled;
459 extern	int tcp_do_newreno;
460 extern	int path_mtu_discovery;
461 extern	int ss_fltsz;
462 extern	int ss_fltsz_local;
463 
464 void	 tcp_canceltimers(struct tcpcb *);
465 struct tcpcb *
466 	 tcp_close(struct tcpcb *);
467 void	 tcp_twstart(struct tcpcb *);
468 struct tcptw *
469 	 tcp_twclose(struct tcptw *_tw, int _reuse);
470 void	 tcp_ctlinput(int, struct sockaddr *, void *);
471 int	 tcp_ctloutput(struct socket *, struct sockopt *);
472 struct tcpcb *
473 	 tcp_drop(struct tcpcb *, int);
474 void	 tcp_drain(void);
475 void	 tcp_fasttimo(void);
476 struct rmxp_tao *
477 	 tcp_gettaocache(struct in_conninfo *);
478 void	 tcp_init(void);
479 void	 tcp_input(struct mbuf *, int);
480 void	 tcp_mss(struct tcpcb *, int);
481 int	 tcp_mssopt(struct tcpcb *);
482 struct inpcb *
483 	 tcp_drop_syn_sent(struct inpcb *, int);
484 struct inpcb *
485 	 tcp_mtudisc(struct inpcb *, int);
486 struct tcpcb *
487 	 tcp_newtcpcb(struct inpcb *);
488 int	 tcp_output(struct tcpcb *);
489 struct inpcb *
490 	 tcp_quench(struct inpcb *, int);
491 void	 tcp_respond(struct tcpcb *, void *,
492 	    struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
493 int	 tcp_twrespond(struct tcptw *, int);
494 struct rtentry *
495 	 tcp_rtlookup(struct in_conninfo *);
496 void	 tcp_setpersist(struct tcpcb *);
497 void	 tcp_slowtimo(void);
498 struct tcptemp *
499 	 tcpip_maketemplate(struct inpcb *);
500 void	 tcpip_fillheaders(struct inpcb *, void *, void *);
501 struct tcpcb *
502 	 tcp_timers(struct tcpcb *, int);
503 void	 tcp_trace(int, int, struct tcpcb *, void *, struct tcphdr *, int);
504 void	 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
505 void	 syncache_init(void);
506 void	 syncache_unreach(struct in_conninfo *, struct tcphdr *);
507 int	 syncache_expand(struct in_conninfo *, struct tcphdr *,
508 	     struct socket **, struct mbuf *);
509 int	 syncache_add(struct in_conninfo *, struct tcpopt *,
510 	     struct tcphdr *, struct socket **, struct mbuf *);
511 void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *);
512 void	 syncache_badack(struct in_conninfo *);
513 
514 extern	struct pr_usrreqs tcp_usrreqs;
515 extern	u_long tcp_sendspace;
516 extern	u_long tcp_recvspace;
517 tcp_seq tcp_new_isn(struct tcpcb *);
518 
519 #endif /* _KERNEL */
520 
521 #endif /* _NETINET_TCP_VAR_H_ */
522