FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_var.h
1 /* $NetBSD: tcp_var.h,v 1.123.2.2 2005/05/06 08:35:20 tron 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 * 3. All advertising materials mentioning features or use of this software
91 * must display the following acknowledgement:
92 * This product includes software developed by the NetBSD
93 * Foundation, Inc. and its contributors.
94 * 4. Neither the name of The NetBSD Foundation nor the names of its
95 * contributors may be used to endorse or promote products derived
96 * from this software without specific prior written permission.
97 *
98 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
99 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
100 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
101 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
102 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
103 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
104 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
105 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
106 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
107 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
108 * POSSIBILITY OF SUCH DAMAGE.
109 */
110
111 /*
112 * Copyright (c) 1982, 1986, 1993, 1994, 1995
113 * The Regents of the University of California. All rights reserved.
114 *
115 * Redistribution and use in source and binary forms, with or without
116 * modification, are permitted provided that the following conditions
117 * are met:
118 * 1. Redistributions of source code must retain the above copyright
119 * notice, this list of conditions and the following disclaimer.
120 * 2. Redistributions in binary form must reproduce the above copyright
121 * notice, this list of conditions and the following disclaimer in the
122 * documentation and/or other materials provided with the distribution.
123 * 3. Neither the name of the University nor the names of its contributors
124 * may be used to endorse or promote products derived from this software
125 * without specific prior written permission.
126 *
127 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
128 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
129 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
130 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
131 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
132 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
133 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
134 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
135 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
136 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
137 * SUCH DAMAGE.
138 *
139 * @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
140 */
141
142 #ifndef _NETINET_TCP_VAR_H_
143 #define _NETINET_TCP_VAR_H_
144
145 #if defined(_KERNEL_OPT)
146 #include "opt_inet.h"
147 #include "opt_mbuftrace.h"
148 #endif
149
150 /*
151 * Kernel variables for tcp.
152 */
153
154 #include <sys/callout.h>
155
156 #ifdef TCP_SIGNATURE
157 /*
158 * Defines which are needed by the xform_tcp module and tcp_[in|out]put
159 * for SADB verification and lookup.
160 */
161 #define TCP_SIGLEN 16 /* length of computed digest in bytes */
162 #define TCP_KEYLEN_MIN 1 /* minimum length of TCP-MD5 key */
163 #define TCP_KEYLEN_MAX 80 /* maximum length of TCP-MD5 key */
164 /*
165 * Only a single SA per host may be specified at this time. An SPI is
166 * needed in order for the KEY_ALLOCSA() lookup to work.
167 */
168 #define TCP_SIG_SPI 0x1000
169 #endif /* TCP_SIGNATURE */
170
171 /*
172 * SACK option block.
173 */
174 struct sackblk {
175 tcp_seq left; /* Left edge of sack block. */
176 tcp_seq right; /* Right edge of sack block. */
177 };
178
179 TAILQ_HEAD(sackhead, sackhole);
180 struct sackhole {
181 tcp_seq start;
182 tcp_seq end;
183 tcp_seq rxmit;
184
185 TAILQ_ENTRY(sackhole) sackhole_q;
186 };
187
188 /*
189 * Tcp control block, one per tcp; fields:
190 */
191 struct tcpcb {
192 int t_family; /* address family on the wire */
193 struct ipqehead segq; /* sequencing queue */
194 int t_segqlen; /* length of the above */
195 struct callout t_timer[TCPT_NTIMERS];/* tcp timers */
196 short t_state; /* state of this connection */
197 short t_rxtshift; /* log(2) of rexmt exp. backoff */
198 uint32_t t_rxtcur; /* current retransmit value */
199 short t_dupacks; /* consecutive dup acks recd */
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_SIGNATURE 0x400000 /* require MD5 digests (RFC2385) */
220
221
222 struct mbuf *t_template; /* skeletal packet for transmit */
223 struct inpcb *t_inpcb; /* back pointer to internet pcb */
224 struct in6pcb *t_in6pcb; /* back pointer to internet pcb */
225 struct callout t_delack_ch; /* delayed ACK callout */
226 /*
227 * The following fields are used as in the protocol specification.
228 * See RFC783, Dec. 1981, page 21.
229 */
230 /* send sequence variables */
231 tcp_seq snd_una; /* send unacknowledged */
232 tcp_seq snd_nxt; /* send next */
233 tcp_seq snd_up; /* send urgent pointer */
234 tcp_seq snd_wl1; /* window update seg seq number */
235 tcp_seq snd_wl2; /* window update seg ack number */
236 tcp_seq iss; /* initial send sequence number */
237 u_long snd_wnd; /* send window */
238 tcp_seq snd_recover; /* for use in fast recovery */
239 tcp_seq snd_high; /* NewReno false fast rexmit seq */
240 /* receive sequence variables */
241 u_long rcv_wnd; /* receive window */
242 tcp_seq rcv_nxt; /* receive next */
243 tcp_seq rcv_up; /* receive urgent pointer */
244 tcp_seq irs; /* initial receive sequence number */
245 /*
246 * Additional variables for this implementation.
247 */
248 /* receive variables */
249 tcp_seq rcv_adv; /* advertised window */
250 /* retransmit variables */
251 tcp_seq snd_max; /* highest sequence number sent;
252 * used to recognize retransmits
253 */
254 /* congestion control (for slow start, source quench, retransmit after loss) */
255 u_long snd_cwnd; /* congestion-controlled window */
256 u_long snd_ssthresh; /* snd_cwnd size threshhold for
257 * for slow start exponential to
258 * linear switch
259 */
260 /*
261 * transmit timing stuff. See below for scale of srtt and rttvar.
262 * "Variance" is actually smoothed difference.
263 */
264 uint32_t t_rcvtime; /* time last segment received */
265 uint32_t t_rtttime; /* time we started measuring rtt */
266 tcp_seq t_rtseq; /* sequence number being timed */
267 int32_t t_srtt; /* smoothed round-trip time */
268 int32_t t_rttvar; /* variance in round-trip time */
269 uint32_t t_rttmin; /* minimum rtt allowed */
270 u_long max_sndwnd; /* largest window peer has offered */
271
272 /* out-of-band data */
273 char t_oobflags; /* have some */
274 char t_iobc; /* input character */
275 #define TCPOOB_HAVEDATA 0x01
276 #define TCPOOB_HADDATA 0x02
277 short t_softerror; /* possible error not yet reported */
278
279 /* RFC 1323 variables */
280 u_char snd_scale; /* window scaling for send window */
281 u_char rcv_scale; /* window scaling for recv window */
282 u_char request_r_scale; /* pending window scaling */
283 u_char requested_s_scale;
284 u_int32_t ts_recent; /* timestamp echo data */
285 u_int32_t ts_recent_age; /* when last updated */
286 u_int32_t ts_timebase; /* our timebase */
287 tcp_seq last_ack_sent;
288
289 /* SACK stuff */
290 #define TCP_SACK_MAX 3
291 #define TCPSACK_NONE 0
292 #define TCPSACK_HAVED 1
293 u_char rcv_sack_flags; /* SACK flags. */
294 struct sackblk rcv_dsack_block; /* RX D-SACK block. */
295 struct ipqehead timeq; /* time sequenced queue. */
296 struct sackhead snd_holes; /* TX SACK holes. */
297 int snd_numholes; /* Number of TX SACK holes. */
298 tcp_seq rcv_lastsack; /* last seq number(+1) sack'd by rcv'r*/
299 tcp_seq sack_newdata; /* New data xmitted in this recovery
300 episode starts at this seq number*/
301 tcp_seq snd_fack; /* FACK TCP. Forward-most data held by
302 peer. */
303
304 /* path MTU discovery blackhole detection */
305 int t_mtudisc; /* perform mtudisc for this tcb */
306
307 /* pointer for syn cache entries*/
308 LIST_HEAD(, syn_cache) t_sc; /* list of entries by this tcb */
309
310 /* prediction of next mbuf when using large window sizes */
311 struct mbuf *t_lastm; /* last mbuf that data was sent from */
312 int t_inoff; /* data offset in previous mbuf */
313 int t_lastoff; /* last data address in mbuf chain */
314 int t_lastlen; /* last length read from mbuf chain */
315 };
316
317 /*
318 * Macros to aid SACK/FACK TCP.
319 */
320 #define TCP_SACK_ENABLED(tp) (tp->t_flags & TF_WILL_SACK)
321 #define TCP_FACK_FASTRECOV(tp) \
322 (TCP_SACK_ENABLED(tp) && \
323 (SEQ_GT(tp->snd_fack, tp->snd_una + tcprexmtthresh * tp->t_segsz)))
324
325 #ifdef _KERNEL
326 /*
327 * TCP reassembly queue locks.
328 */
329 static __inline int tcp_reass_lock_try (struct tcpcb *)
330 __attribute__((__unused__));
331 static __inline void tcp_reass_unlock (struct tcpcb *)
332 __attribute__((__unused__));
333
334 static __inline int
335 tcp_reass_lock_try(tp)
336 struct tcpcb *tp;
337 {
338 int s;
339
340 /*
341 * Use splvm() -- we're blocking things that would cause
342 * mbuf allocation.
343 */
344 s = splvm();
345 if (tp->t_flags & TF_REASSEMBLING) {
346 splx(s);
347 return (0);
348 }
349 tp->t_flags |= TF_REASSEMBLING;
350 splx(s);
351 return (1);
352 }
353
354 static __inline void
355 tcp_reass_unlock(tp)
356 struct tcpcb *tp;
357 {
358 int s;
359
360 s = splvm();
361 tp->t_flags &= ~TF_REASSEMBLING;
362 splx(s);
363 }
364
365 #ifdef DIAGNOSTIC
366 #define TCP_REASS_LOCK(tp) \
367 do { \
368 if (tcp_reass_lock_try(tp) == 0) { \
369 printf("%s:%d: tcpcb %p reass already locked\n", \
370 __FILE__, __LINE__, tp); \
371 panic("tcp_reass_lock"); \
372 } \
373 } while (/*CONSTCOND*/ 0)
374 #define TCP_REASS_LOCK_CHECK(tp) \
375 do { \
376 if (((tp)->t_flags & TF_REASSEMBLING) == 0) { \
377 printf("%s:%d: tcpcb %p reass lock not held\n", \
378 __FILE__, __LINE__, tp); \
379 panic("tcp reass lock check"); \
380 } \
381 } while (/*CONSTCOND*/ 0)
382 #else
383 #define TCP_REASS_LOCK(tp) (void) tcp_reass_lock_try((tp))
384 #define TCP_REASS_LOCK_CHECK(tp) /* nothing */
385 #endif
386
387 #define TCP_REASS_UNLOCK(tp) tcp_reass_unlock((tp))
388 #endif /* _KERNEL */
389
390 /*
391 * Queue for delayed ACK processing.
392 */
393 #ifdef _KERNEL
394 extern int tcp_delack_ticks;
395 void tcp_delack(void *);
396
397 #define TCP_RESTART_DELACK(tp) \
398 callout_reset(&(tp)->t_delack_ch, tcp_delack_ticks, \
399 tcp_delack, tp)
400
401 #define TCP_SET_DELACK(tp) \
402 do { \
403 if (((tp)->t_flags & TF_DELACK) == 0) { \
404 (tp)->t_flags |= TF_DELACK; \
405 TCP_RESTART_DELACK(tp); \
406 } \
407 } while (/*CONSTCOND*/0)
408
409 #define TCP_CLEAR_DELACK(tp) \
410 do { \
411 if ((tp)->t_flags & TF_DELACK) { \
412 (tp)->t_flags &= ~TF_DELACK; \
413 callout_stop(&(tp)->t_delack_ch); \
414 } \
415 } while (/*CONSTCOND*/0)
416 #endif /* _KERNEL */
417
418 /*
419 * Compute the current timestamp for a connection.
420 */
421 #define TCP_TIMESTAMP(tp) (tcp_now - (tp)->ts_timebase)
422
423 /*
424 * Handy way of passing around TCP option info.
425 */
426 struct tcp_opt_info {
427 int ts_present;
428 u_int32_t ts_val;
429 u_int32_t ts_ecr;
430 u_int16_t maxseg;
431 };
432
433 #define TOF_SIGNATURE 0x0040 /* signature option present */
434 #define TOF_SIGLEN 0x0080 /* sigature length valid (RFC2385) */
435
436 /*
437 * Data for the TCP compressed state engine.
438 */
439 union syn_cache_sa {
440 struct sockaddr sa;
441 struct sockaddr_in sin;
442 #if 1 /*def INET6*/
443 struct sockaddr_in6 sin6;
444 #endif
445 };
446
447 struct syn_cache {
448 TAILQ_ENTRY(syn_cache) sc_bucketq; /* link on bucket list */
449 struct callout sc_timer; /* rexmt timer */
450 union { /* cached route */
451 struct route route4;
452 #ifdef INET6
453 struct route_in6 route6;
454 #endif
455 } sc_route_u;
456 #define sc_route4 sc_route_u.route4
457 #ifdef INET6
458 #define sc_route6 sc_route_u.route6
459 #endif
460 long sc_win; /* advertised window */
461 int sc_bucketidx; /* our bucket index */
462 u_int32_t sc_hash;
463 u_int32_t sc_timestamp; /* timestamp from SYN */
464 u_int32_t sc_timebase; /* our local timebase */
465 union syn_cache_sa sc_src;
466 union syn_cache_sa sc_dst;
467 tcp_seq sc_irs;
468 tcp_seq sc_iss;
469 u_int sc_rxtcur; /* current rxt timeout */
470 u_int sc_rxttot; /* total time spend on queues */
471 u_short sc_rxtshift; /* for computing backoff */
472 u_short sc_flags;
473
474 #define SCF_UNREACH 0x0001 /* we've had an unreach error */
475 #define SCF_TIMESTAMP 0x0002 /* peer will do timestamps */
476 #define SCF_DEAD 0x0004 /* this entry to be released */
477 #define SCF_SACK_PERMIT 0x0008 /* peer will do SACK */
478 #define SCF_SIGNATURE 0x40 /* send MD5 digests */
479
480 struct mbuf *sc_ipopts; /* IP options */
481 u_int16_t sc_peermaxseg;
482 u_int16_t sc_ourmaxseg;
483 u_int8_t sc_request_r_scale : 4,
484 sc_requested_s_scale : 4;
485
486 struct tcpcb *sc_tp; /* tcb for listening socket */
487 LIST_ENTRY(syn_cache) sc_tpq; /* list of entries by same tp */
488 };
489
490 struct syn_cache_head {
491 TAILQ_HEAD(, syn_cache) sch_bucket; /* bucket entries */
492 u_short sch_length; /* # entries in bucket */
493 };
494
495 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
496 #ifdef INET6
497 #define in6totcpcb(ip) ((struct tcpcb *)(ip)->in6p_ppcb)
498 #endif
499 #ifndef INET6
500 #define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
501 #else
502 #define sototcpcb(so) (((so)->so_proto->pr_domain->dom_family == AF_INET) \
503 ? intotcpcb(sotoinpcb(so)) \
504 : in6totcpcb(sotoin6pcb(so)))
505 #endif
506
507 /*
508 * The smoothed round-trip time and estimated variance
509 * are stored as fixed point numbers scaled by the values below.
510 * For convenience, these scales are also used in smoothing the average
511 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
512 * With these scales, srtt has 3 bits to the right of the binary point,
513 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
514 * binary point, and is smoothed with an ALPHA of 0.75.
515 */
516 #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */
517 #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */
518
519 /*
520 * The initial retransmission should happen at rtt + 4 * rttvar.
521 * Because of the way we do the smoothing, srtt and rttvar
522 * will each average +1/2 tick of bias. When we compute
523 * the retransmit timer, we want 1/2 tick of rounding and
524 * 1 extra tick because of +-1/2 tick uncertainty in the
525 * firing of the timer. The bias will give us exactly the
526 * 1.5 tick we need. But, because the bias is
527 * statistical, we have to test that we don't drop below
528 * the minimum feasible timer (which is 2 ticks).
529 * This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT
530 * is the same as the multiplier for rttvar.
531 */
532 #define TCP_REXMTVAL(tp) \
533 ((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2)
534
535 /*
536 * Compute the initial window for slow start.
537 */
538 #define TCP_INITIAL_WINDOW(iw, segsz) \
539 (((iw) == 0) ? (min(4 * (segsz), max(2 * (segsz), 4380))) : \
540 ((segsz) * (iw)))
541
542 /*
543 * TCP statistics.
544 * Many of these should be kept per connection,
545 * but that's inconvenient at the moment.
546 */
547 struct tcpstat {
548 u_quad_t tcps_connattempt; /* connections initiated */
549 u_quad_t tcps_accepts; /* connections accepted */
550 u_quad_t tcps_connects; /* connections established */
551 u_quad_t tcps_drops; /* connections dropped */
552 u_quad_t tcps_conndrops; /* embryonic connections dropped */
553 u_quad_t tcps_closed; /* conn. closed (includes drops) */
554 u_quad_t tcps_segstimed; /* segs where we tried to get rtt */
555 u_quad_t tcps_rttupdated; /* times we succeeded */
556 u_quad_t tcps_delack; /* delayed acks sent */
557 u_quad_t tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
558 u_quad_t tcps_rexmttimeo; /* retransmit timeouts */
559 u_quad_t tcps_persisttimeo; /* persist timeouts */
560 u_quad_t tcps_keeptimeo; /* keepalive timeouts */
561 u_quad_t tcps_keepprobe; /* keepalive probes sent */
562 u_quad_t tcps_keepdrops; /* connections dropped in keepalive */
563 u_quad_t tcps_persistdrops; /* connections dropped in persist */
564 u_quad_t tcps_connsdrained; /* connections drained due to memory
565 shortage */
566 u_quad_t tcps_pmtublackhole; /* PMTUD blackhole detected */
567
568 u_quad_t tcps_sndtotal; /* total packets sent */
569 u_quad_t tcps_sndpack; /* data packets sent */
570 u_quad_t tcps_sndbyte; /* data bytes sent */
571 u_quad_t tcps_sndrexmitpack; /* data packets retransmitted */
572 u_quad_t tcps_sndrexmitbyte; /* data bytes retransmitted */
573 u_quad_t tcps_sndacks; /* ack-only packets sent */
574 u_quad_t tcps_sndprobe; /* window probes sent */
575 u_quad_t tcps_sndurg; /* packets sent with URG only */
576 u_quad_t tcps_sndwinup; /* window update-only packets sent */
577 u_quad_t tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
578
579 u_quad_t tcps_rcvtotal; /* total packets received */
580 u_quad_t tcps_rcvpack; /* packets received in sequence */
581 u_quad_t tcps_rcvbyte; /* bytes received in sequence */
582 u_quad_t tcps_rcvbadsum; /* packets received with ccksum errs */
583 u_quad_t tcps_rcvbadoff; /* packets received with bad offset */
584 u_quad_t tcps_rcvmemdrop; /* packets dropped for lack of memory */
585 u_quad_t tcps_rcvshort; /* packets received too short */
586 u_quad_t tcps_rcvduppack; /* duplicate-only packets received */
587 u_quad_t tcps_rcvdupbyte; /* duplicate-only bytes received */
588 u_quad_t tcps_rcvpartduppack; /* packets with some duplicate data */
589 u_quad_t tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
590 u_quad_t tcps_rcvoopack; /* out-of-order packets received */
591 u_quad_t tcps_rcvoobyte; /* out-of-order bytes received */
592 u_quad_t tcps_rcvpackafterwin; /* packets with data after window */
593 u_quad_t tcps_rcvbyteafterwin; /* bytes rcvd after window */
594 u_quad_t tcps_rcvafterclose; /* packets rcvd after "close" */
595 u_quad_t tcps_rcvwinprobe; /* rcvd window probe packets */
596 u_quad_t tcps_rcvdupack; /* rcvd duplicate acks */
597 u_quad_t tcps_rcvacktoomuch; /* rcvd acks for unsent data */
598 u_quad_t tcps_rcvackpack; /* rcvd ack packets */
599 u_quad_t tcps_rcvackbyte; /* bytes acked by rcvd acks */
600 u_quad_t tcps_rcvwinupd; /* rcvd window update packets */
601 u_quad_t tcps_pawsdrop; /* segments dropped due to PAWS */
602 u_quad_t tcps_predack; /* times hdr predict ok for acks */
603 u_quad_t tcps_preddat; /* times hdr predict ok for data pkts */
604
605 u_quad_t tcps_pcbhashmiss; /* input packets missing pcb hash */
606 u_quad_t tcps_noport; /* no socket on port */
607 u_quad_t tcps_badsyn; /* received ack for which we have
608 no SYN in compressed state */
609 u_quad_t tcps_delayed_free; /* delayed pool_put() of tcpcb */
610
611 /* These statistics deal with the SYN cache. */
612 u_quad_t tcps_sc_added; /* # of entries added */
613 u_quad_t tcps_sc_completed; /* # of connections completed */
614 u_quad_t tcps_sc_timed_out; /* # of entries timed out */
615 u_quad_t tcps_sc_overflowed; /* # dropped due to overflow */
616 u_quad_t tcps_sc_reset; /* # dropped due to RST */
617 u_quad_t tcps_sc_unreach; /* # dropped due to ICMP unreach */
618 u_quad_t tcps_sc_bucketoverflow;/* # dropped due to bucket overflow */
619 u_quad_t tcps_sc_aborted; /* # of entries aborted (no mem) */
620 u_quad_t tcps_sc_dupesyn; /* # of duplicate SYNs received */
621 u_quad_t tcps_sc_dropped; /* # of SYNs dropped (no route/mem) */
622 u_quad_t tcps_sc_collisions; /* # of hash collisions */
623 u_quad_t tcps_sc_retransmitted; /* # of retransmissions */
624 u_quad_t tcps_sc_delayed_free; /* # of delayed pool_put()s */
625
626 u_quad_t tcps_selfquench; /* # of ENOBUFS we get on output */
627 u_quad_t tcps_badsig; /* # of drops due to bad signature */
628 u_quad_t tcps_goodsig; /* # of packets with good signature */
629 };
630
631 /*
632 * Names for TCP sysctl objects.
633 */
634 #define TCPCTL_RFC1323 1 /* RFC1323 timestamps/scaling */
635 #define TCPCTL_SENDSPACE 2 /* default send buffer */
636 #define TCPCTL_RECVSPACE 3 /* default recv buffer */
637 #define TCPCTL_MSSDFLT 4 /* default seg size */
638 #define TCPCTL_SYN_CACHE_LIMIT 5 /* max size of comp. state engine */
639 #define TCPCTL_SYN_BUCKET_LIMIT 6 /* max size of hash bucket */
640 #if 0 /*obsoleted*/
641 #define TCPCTL_SYN_CACHE_INTER 7 /* interval of comp. state timer */
642 #endif
643 #define TCPCTL_INIT_WIN 8 /* initial window */
644 #define TCPCTL_MSS_IFMTU 9 /* mss from interface, not in_maxmtu */
645 #define TCPCTL_SACK 10 /* RFC2018 selective acknowledgement */
646 #define TCPCTL_WSCALE 11 /* RFC1323 window scaling */
647 #define TCPCTL_TSTAMP 12 /* RFC1323 timestamps */
648 #define TCPCTL_COMPAT_42 13 /* 4.2BSD TCP bug work-arounds */
649 #define TCPCTL_CWM 14 /* Congestion Window Monitoring */
650 #define TCPCTL_CWM_BURSTSIZE 15 /* burst size allowed by CWM */
651 #define TCPCTL_ACK_ON_PUSH 16 /* ACK immediately on PUSH */
652 #define TCPCTL_KEEPIDLE 17 /* keepalive idle time */
653 #define TCPCTL_KEEPINTVL 18 /* keepalive probe interval */
654 #define TCPCTL_KEEPCNT 19 /* keepalive count */
655 #define TCPCTL_SLOWHZ 20 /* PR_SLOWHZ (read-only) */
656 #define TCPCTL_NEWRENO 21 /* NewReno Congestion Control */
657 #define TCPCTL_LOG_REFUSED 22 /* Log refused connections */
658 #if 0 /*obsoleted*/
659 #define TCPCTL_RSTRATELIMIT 23 /* RST rate limit */
660 #endif
661 #define TCPCTL_RSTPPSLIMIT 24 /* RST pps limit */
662 #define TCPCTL_DELACK_TICKS 25 /* # ticks to delay ACK */
663 #define TCPCTL_INIT_WIN_LOCAL 26 /* initial window for local nets */
664 #define TCPCTL_IDENT 27 /* rfc 931 identd */
665 #define TCPCTL_ACKDROPRATELIMIT 28 /* SYN/RST -> ACK rate limit */
666 #define TCPCTL_LOOPBACKCKSUM 29 /* do TCP checksum on loopback */
667 #define TCPCTL_MAXID 30
668
669 #define TCPCTL_NAMES { \
670 { 0, 0 }, \
671 { "rfc1323", CTLTYPE_INT }, \
672 { "sendspace", CTLTYPE_INT }, \
673 { "recvspace", CTLTYPE_INT }, \
674 { "mssdflt", CTLTYPE_INT }, \
675 { "syn_cache_limit", CTLTYPE_INT }, \
676 { "syn_bucket_limit", CTLTYPE_INT }, \
677 { 0, 0 },\
678 { "init_win", CTLTYPE_INT }, \
679 { "mss_ifmtu", CTLTYPE_INT }, \
680 { "sack", CTLTYPE_INT }, \
681 { "win_scale", CTLTYPE_INT }, \
682 { "timestamps", CTLTYPE_INT }, \
683 { "compat_42", CTLTYPE_INT }, \
684 { "cwm", CTLTYPE_INT }, \
685 { "cwm_burstsize", CTLTYPE_INT }, \
686 { "ack_on_push", CTLTYPE_INT }, \
687 { "keepidle", CTLTYPE_INT }, \
688 { "keepintvl", CTLTYPE_INT }, \
689 { "keepcnt", CTLTYPE_INT }, \
690 { "slowhz", CTLTYPE_INT }, \
691 { "newreno", CTLTYPE_INT }, \
692 { "log_refused",CTLTYPE_INT }, \
693 { 0, 0 }, \
694 { "rstppslimit", CTLTYPE_INT }, \
695 { "delack_ticks", CTLTYPE_INT }, \
696 { "init_win_local", CTLTYPE_INT }, \
697 { "ident", CTLTYPE_STRUCT }, \
698 { "ackdropppslimit", CTLTYPE_INT }, \
699 { "do_loopback_cksum", CTLTYPE_INT }, \
700 }
701
702 #ifdef _KERNEL
703 extern struct inpcbtable tcbtable; /* head of queue of active tcpcb's */
704 extern struct tcpstat tcpstat; /* tcp statistics */
705 extern u_int32_t tcp_now; /* for RFC 1323 timestamps */
706 extern int tcp_do_rfc1323; /* enabled/disabled? */
707 extern int tcp_do_sack; /* SACK enabled/disabled? */
708 extern int tcp_do_win_scale; /* RFC1323 window scaling enabled/disabled? */
709 extern int tcp_do_timestamps; /* RFC1323 timestamps enabled/disabled? */
710 extern int tcp_do_newreno; /* Use the New Reno algorithms */
711 extern int tcp_mssdflt; /* default seg size */
712 extern int tcp_init_win; /* initial window */
713 extern int tcp_init_win_local; /* initial window for local nets */
714 extern int tcp_mss_ifmtu; /* take MSS from interface, not in_maxmtu */
715 extern int tcp_compat_42; /* work around ancient broken TCP peers */
716 extern int tcp_cwm; /* enable Congestion Window Monitoring */
717 extern int tcp_cwm_burstsize; /* burst size allowed by CWM */
718 extern int tcp_ack_on_push; /* ACK immediately on PUSH */
719 extern int tcp_syn_cache_limit; /* max entries for compressed state engine */
720 extern int tcp_syn_bucket_limit;/* max entries per hash bucket */
721 extern int tcp_log_refused; /* log refused connections */
722 extern int tcp_do_loopback_cksum;/* do TCP checksum on loopback? */
723 extern int tcp_sack_tp_maxholes; /* Max holes per connection. */
724 extern int tcp_sack_globalmaxholes; /* Max holes per system. */
725 extern int tcp_sack_globalholes; /* Number of holes present. */
726
727 extern int tcp_rst_ppslim;
728 extern int tcp_ackdrop_ppslim;
729
730 extern int tcp_syn_cache_size;
731 extern struct syn_cache_head tcp_syn_cache[];
732 extern u_long syn_cache_count;
733
734 #ifdef MBUFTRACE
735 extern struct mowner tcp_rx_mowner;
736 extern struct mowner tcp_tx_mowner;
737 extern struct mowner tcp_mowner;
738 #endif
739
740 #define TCPCTL_VARIABLES { \
741 { 0 }, \
742 { 1, 0, &tcp_do_rfc1323 }, \
743 { 1, 0, &tcp_sendspace }, \
744 { 1, 0, &tcp_recvspace }, \
745 { 1, 0, &tcp_mssdflt }, \
746 { 1, 0, &tcp_syn_cache_limit }, \
747 { 1, 0, &tcp_syn_bucket_limit }, \
748 { 0 }, \
749 { 1, 0, &tcp_init_win }, \
750 { 1, 0, &tcp_mss_ifmtu }, \
751 { 1, 0, &tcp_do_sack }, \
752 { 1, 0, &tcp_do_win_scale }, \
753 { 1, 0, &tcp_do_timestamps }, \
754 { 1, 0, &tcp_compat_42 }, \
755 { 1, 0, &tcp_cwm }, \
756 { 1, 0, &tcp_cwm_burstsize }, \
757 { 1, 0, &tcp_ack_on_push }, \
758 { 1, 0, &tcp_keepidle }, \
759 { 1, 0, &tcp_keepintvl }, \
760 { 1, 0, &tcp_keepcnt }, \
761 { 1, 1, 0, PR_SLOWHZ }, \
762 { 1, 0, &tcp_do_newreno }, \
763 { 1, 0, &tcp_log_refused }, \
764 { 0 }, \
765 { 1, 0, &tcp_rst_ppslim }, \
766 { 1, 0, &tcp_delack_ticks }, \
767 { 1, 0, &tcp_init_win_local }, \
768 { 1, 0, &tcp_ackdrop_ppslim }, \
769 }
770
771 #ifdef __NO_STRICT_ALIGNMENT
772 #define TCP_HDR_ALIGNED_P(th) 1
773 #else
774 #define TCP_HDR_ALIGNED_P(th) ((((vaddr_t)(th)) & 3) == 0)
775 #endif
776
777 struct secasvar;
778
779 int tcp_attach(struct socket *);
780 void tcp_canceltimers(struct tcpcb *);
781 int tcp_timers_invoking(struct tcpcb*);
782 struct tcpcb *
783 tcp_close(struct tcpcb *);
784 int tcp_isdead(struct tcpcb *);
785 #ifdef INET6
786 void tcp6_ctlinput(int, struct sockaddr *, void *);
787 #endif
788 void *tcp_ctlinput(int, struct sockaddr *, void *);
789 int tcp_ctloutput(int, struct socket *, int, int, struct mbuf **);
790 struct tcpcb *
791 tcp_disconnect(struct tcpcb *);
792 struct tcpcb *
793 tcp_drop(struct tcpcb *, int);
794 #ifdef TCP_SIGNATURE
795 int tcp_signature_apply(void *, caddr_t, u_int);
796 struct secasvar *tcp_signature_getsav(struct mbuf *, struct tcphdr *);
797 int tcp_signature(struct mbuf *, struct tcphdr *, int, struct secasvar *,
798 char *);
799 #endif
800 int tcp_dooptions(struct tcpcb *, u_char *, int, struct tcphdr *,
801 struct mbuf *, int, struct tcp_opt_info *);
802 void tcp_drain(void);
803 void tcp_established(struct tcpcb *);
804 void tcp_init(void);
805 #ifdef INET6
806 int tcp6_input(struct mbuf **, int *, int);
807 #endif
808 void tcp_input(struct mbuf *, ...);
809 u_long tcp_mss_to_advertise(const struct ifnet *, int);
810 void tcp_mss_from_peer(struct tcpcb *, int);
811 void tcp_tcpcb_template(void);
812 struct tcpcb *
813 tcp_newtcpcb(int, void *);
814 void tcp_notify(struct inpcb *, int);
815 #ifdef INET6
816 void tcp6_notify(struct in6pcb *, int);
817 #endif
818 u_int tcp_optlen(struct tcpcb *);
819 int tcp_output(struct tcpcb *);
820 void tcp_pulloutofband(struct socket *,
821 struct tcphdr *, struct mbuf *, int);
822 void tcp_quench(struct inpcb *, int);
823 #ifdef INET6
824 void tcp6_quench(struct in6pcb *, int);
825 #endif
826
827 struct ipqent *tcpipqent_alloc(void);
828 void tcpipqent_free(struct ipqent *);
829
830 int tcp_reass(struct tcpcb *, struct tcphdr *, struct mbuf *, int *);
831 int tcp_respond(struct tcpcb *, struct mbuf *, struct mbuf *,
832 struct tcphdr *, tcp_seq, tcp_seq, int);
833 void tcp_rmx_rtt(struct tcpcb *);
834 void tcp_setpersist(struct tcpcb *);
835 #ifdef TCP_SIGNATURE
836 int tcp_signature_compute(struct mbuf *, struct tcphdr *, int, int,
837 int, u_char *, u_int);
838 #endif
839 void tcp_slowtimo(void);
840 struct mbuf *
841 tcp_template(struct tcpcb *);
842 void tcp_trace(short, short, struct tcpcb *, struct mbuf *, int);
843 struct tcpcb *
844 tcp_usrclosed(struct tcpcb *);
845 int tcp_usrreq(struct socket *,
846 int, struct mbuf *, struct mbuf *, struct mbuf *, struct proc *);
847 void tcp_xmit_timer(struct tcpcb *, uint32_t);
848 tcp_seq tcp_new_iss(struct tcpcb *, tcp_seq);
849 tcp_seq tcp_new_iss1(void *, void *, u_int16_t, u_int16_t, size_t,
850 tcp_seq);
851
852 void tcp_new_dsack(struct tcpcb *, tcp_seq, u_int32_t);
853 void tcp_sack_option(struct tcpcb *, struct tcphdr *, u_char *, int);
854 void tcp_del_sackholes(struct tcpcb *, struct tcphdr *);
855 void tcp_free_sackholes(struct tcpcb *);
856 void tcp_sack_adjust(struct tcpcb *tp);
857 struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
858 void tcp_sack_newack(struct tcpcb *, struct tcphdr *);
859 int tcp_sack_numblks(const struct tcpcb *);
860 #define TCP_SACK_OPTLEN(nblks) ((nblks) * 8 + 2 + 2)
861
862 int syn_cache_add(struct sockaddr *, struct sockaddr *,
863 struct tcphdr *, unsigned int, struct socket *,
864 struct mbuf *, u_char *, int, struct tcp_opt_info *);
865 void syn_cache_unreach(struct sockaddr *, struct sockaddr *,
866 struct tcphdr *);
867 struct socket *syn_cache_get(struct sockaddr *, struct sockaddr *,
868 struct tcphdr *, unsigned int, unsigned int,
869 struct socket *so, struct mbuf *);
870 void syn_cache_init(void);
871 void syn_cache_insert(struct syn_cache *, struct tcpcb *);
872 struct syn_cache *syn_cache_lookup(struct sockaddr *, struct sockaddr *,
873 struct syn_cache_head **);
874 void syn_cache_reset(struct sockaddr *, struct sockaddr *,
875 struct tcphdr *);
876 int syn_cache_respond(struct syn_cache *, struct mbuf *);
877 void syn_cache_timer(void *);
878 void syn_cache_cleanup(struct tcpcb *);
879
880 void tcp_reno_newack(struct tcpcb *, struct tcphdr *);
881 void tcp_newreno_newack(struct tcpcb *, struct tcphdr *);
882
883 int tcp_input_checksum(int, struct mbuf *, const struct tcphdr *, int, int,
884 int);
885 #endif
886
887 #endif /* _NETINET_TCP_VAR_H_ */
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