sys/netinet/tcp_var.h

   1 /*      $NetBSD: tcp_var.h,v 1.161 2009/09/09 22:41:28 darran 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         short   t_partialacks;          /* partials acks during fast rexmit */
 195         u_short t_peermss;              /* peer's maximum segment size */
 196         u_short t_ourmss;               /* our's maximum segment size */
 197         u_short t_segsz;                /* current segment size in use */
 198         char    t_force;                /* 1 if forcing out a byte */
 199         u_int   t_flags;
 200 #define TF_ACKNOW       0x0001          /* ack peer immediately */
 201 #define TF_DELACK       0x0002          /* ack, but try to delay it */
 202 #define TF_NODELAY      0x0004          /* don't delay packets to coalesce */
 203 #define TF_NOOPT        0x0008          /* don't use tcp options */
 204 #define TF_REQ_SCALE    0x0020          /* have/will request window scaling */
 205 #define TF_RCVD_SCALE   0x0040          /* other side has requested scaling */
 206 #define TF_REQ_TSTMP    0x0080          /* have/will request timestamps */
 207 #define TF_RCVD_TSTMP   0x0100          /* a timestamp was received in SYN */
 208 #define TF_SACK_PERMIT  0x0200          /* other side said I could SACK */
 209 #define TF_SYN_REXMT    0x0400          /* rexmit timer fired on SYN */
 210 #define TF_WILL_SACK    0x0800          /* try to use SACK */
 211 #define TF_REASSEMBLING 0x1000          /* we're busy reassembling */
 212 #define TF_DEAD         0x2000          /* dead and to-be-released */
 213 #define TF_PMTUD_PEND   0x4000          /* Path MTU Discovery pending */
 214 #define TF_ECN_PERMIT   0x10000         /* other side said is ECN-ready */
 215 #define TF_ECN_SND_CWR  0x20000         /* ECN CWR in queue */
 216 #define TF_ECN_SND_ECE  0x40000         /* ECN ECE in queue */
 217 #define TF_SIGNATURE    0x400000        /* require MD5 digests (RFC2385) */
 218
 219
 220         struct  mbuf *t_template;       /* skeletal packet for transmit */
 221         struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
 222         struct  in6pcb *t_in6pcb;       /* back pointer to internet pcb */
 223         callout_t t_delack_ch;          /* delayed ACK callout */
 224 /*
 225  * The following fields are used as in the protocol specification.
 226  * See RFC793, Dec. 1981, page 21.
 227  */
 228 /* send sequence variables */
 229         tcp_seq snd_una;                /* send unacknowledged */
 230         tcp_seq snd_nxt;                /* send next */
 231         tcp_seq snd_up;                 /* send urgent pointer */
 232         tcp_seq snd_wl1;                /* window update seg seq number */
 233         tcp_seq snd_wl2;                /* window update seg ack number */
 234         tcp_seq iss;                    /* initial send sequence number */
 235         u_long  snd_wnd;                /* send window */
 236         tcp_seq snd_recover;            /* for use in fast recovery */
 237         tcp_seq snd_high;               /* NewReno false fast rexmit seq */
 238 /* receive sequence variables */
 239         u_long  rcv_wnd;                /* receive window */
 240         tcp_seq rcv_nxt;                /* receive next */
 241         tcp_seq rcv_up;                 /* receive urgent pointer */
 242         tcp_seq irs;                    /* initial receive sequence number */
 243 /*
 244  * Additional variables for this implementation.
 245  */
 246 /* receive variables */
 247         tcp_seq rcv_adv;                /* advertised window */
 248 /* retransmit variables */
 249         tcp_seq snd_max;                /* highest sequence number sent;
 250                                          * used to recognize retransmits
 251                                          */
 252 /* congestion control (for slow start, source quench, retransmit after loss) */
 253         u_long  snd_cwnd;               /* congestion-controlled window */
 254         u_long  snd_ssthresh;           /* snd_cwnd size threshhold for
 255                                          * for slow start exponential to
 256                                          * linear switch
 257                                          */
 258 /* auto-sizing variables */
 259         u_int rfbuf_cnt;                /* recv buffer autoscaling byte count */
 260         uint32_t rfbuf_ts;              /* recv buffer autoscaling timestamp */
 261
 262 /*
 263  * transmit timing stuff.  See below for scale of srtt and rttvar.
 264  * "Variance" is actually smoothed difference.
 265  */
 266         uint32_t t_rcvtime;             /* time last segment received */
 267         uint32_t t_rtttime;             /* time we started measuring rtt */
 268         tcp_seq t_rtseq;                /* sequence number being timed */
 269         int32_t t_srtt;                 /* smoothed round-trip time */
 270         int32_t t_rttvar;               /* variance in round-trip time */
 271         uint32_t t_rttmin;              /* minimum rtt allowed */
 272         u_long  max_sndwnd;             /* largest window peer has offered */
 273
 274 /* out-of-band data */
 275         char    t_oobflags;             /* have some */
 276         char    t_iobc;                 /* input character */
 277 #define TCPOOB_HAVEDATA 0x01
 278 #define TCPOOB_HADDATA  0x02
 279         short   t_softerror;            /* possible error not yet reported */
 280
 281 /* RFC 1323 variables */
 282         u_char  snd_scale;              /* window scaling for send window */
 283         u_char  rcv_scale;              /* window scaling for recv window */
 284         u_char  request_r_scale;        /* pending window scaling */
 285         u_char  requested_s_scale;
 286         u_int32_t ts_recent;            /* timestamp echo data */
 287         u_int32_t ts_recent_age;        /* when last updated */
 288         u_int32_t ts_timebase;          /* our timebase */
 289         tcp_seq last_ack_sent;
 290
 291 /* RFC 3465 variables */
 292         u_long  t_bytes_acked;          /* ABC "bytes_acked" parameter */
 293
 294 /* SACK stuff */
 295 #define TCP_SACK_MAX 3
 296 #define TCPSACK_NONE 0
 297 #define TCPSACK_HAVED 1
 298         u_char rcv_sack_flags;          /* SACK flags. */
 299         struct sackblk rcv_dsack_block; /* RX D-SACK block. */
 300         struct ipqehead timeq;          /* time sequenced queue. */
 301         struct sackhead snd_holes;      /* TX SACK holes. */
 302         int     snd_numholes;           /* Number of TX SACK holes. */
 303         tcp_seq rcv_lastsack;           /* last seq number(+1) sack'd by rcv'r*/
 304         tcp_seq sack_newdata;           /* New data xmitted in this recovery
 305                                            episode starts at this seq number*/
 306         tcp_seq snd_fack;               /* FACK TCP.  Forward-most data held by
 307                                            peer. */
 308
 309 /* pointer for syn cache entries*/
 310         LIST_HEAD(, syn_cache) t_sc;    /* list of entries by this tcb */
 311
 312 /* prediction of next mbuf when using large window sizes */
 313         struct  mbuf *t_lastm;          /* last mbuf that data was sent from */
 314         int     t_inoff;                /* data offset in previous mbuf */
 315         int     t_lastoff;              /* last data address in mbuf chain */
 316         int     t_lastlen;              /* last length read from mbuf chain */
 317
 318 /* Path-MTU discovery blackhole detection */
 319         int t_mtudisc;                  /* perform mtudisc for this tcb */
 320 /* Path-MTU Discovery Information */
 321         u_int   t_pmtud_mss_acked;      /* MSS acked, lower bound for MTU */
 322         u_int   t_pmtud_mtu_sent;       /* MTU used, upper bound for MTU */
 323         tcp_seq t_pmtud_th_seq;         /* TCP SEQ from ICMP payload */
 324         u_int   t_pmtud_nextmtu;        /* Advertised Next-Hop MTU from ICMP */
 325         u_short t_pmtud_ip_len;         /* IP length from ICMP payload */
 326         u_short t_pmtud_ip_hl;          /* IP header length from ICMP payload */
 327
 328         uint8_t t_ecn_retries;          /* # of ECN setup retries */
 329
 330         const struct tcp_congctl *t_congctl;    /* per TCB congctl algorithm */
 331
 332         /* Keepalive per socket */
 333         u_int   t_keepinit;
 334         u_int   t_keepidle;
 335         u_int   t_keepintvl;
 336         u_int   t_keepcnt;
 337         u_int   t_maxidle;              /* t_keepcnt * t_keepintvl */
 338
 339 };
 340
 341 /*
 342  * Macros to aid ECN TCP.
 343  */
 344 #define TCP_ECN_ALLOWED(tp)     (tp->t_flags & TF_ECN_PERMIT)
 345
 346 /*
 347  * Macros to aid SACK/FACK TCP.
 348  */
 349 #define TCP_SACK_ENABLED(tp)    (tp->t_flags & TF_WILL_SACK)
 350 #define TCP_FACK_FASTRECOV(tp)  \
 351         (TCP_SACK_ENABLED(tp) && \
 352         (SEQ_GT(tp->snd_fack, tp->snd_una + tcprexmtthresh * tp->t_segsz)))
 353
 354 #ifdef _KERNEL
 355 /*
 356  * TCP reassembly queue locks.
 357  */
 358 static __inline int tcp_reass_lock_try (struct tcpcb *)
 359         __unused;
 360 static __inline void tcp_reass_unlock (struct tcpcb *)
 361         __unused;
 362
 363 static __inline int
 364 tcp_reass_lock_try(struct tcpcb *tp)
 365 {
 366         int s;
 367
 368         /*
 369          * Use splvm() -- we're blocking things that would cause
 370          * mbuf allocation.
 371          */
 372         s = splvm();
 373         if (tp->t_flags & TF_REASSEMBLING) {
 374                 splx(s);
 375                 return (0);
 376         }
 377         tp->t_flags |= TF_REASSEMBLING;
 378         splx(s);
 379         return (1);
 380 }
 381
 382 static __inline void
 383 tcp_reass_unlock(struct tcpcb *tp)
 384 {
 385         int s;
 386
 387         s = splvm();
 388         tp->t_flags &= ~TF_REASSEMBLING;
 389         splx(s);
 390 }
 391
 392 #ifdef DIAGNOSTIC
 393 #define TCP_REASS_LOCK(tp)                                              \
 394 do {                                                                    \
 395         if (tcp_reass_lock_try(tp) == 0) {                              \
 396                 printf("%s:%d: tcpcb %p reass already locked\n",        \
 397                     __FILE__, __LINE__, tp);                            \
 398                 panic("tcp_reass_lock");                                \
 399         }                                                               \
 400 } while (/*CONSTCOND*/ 0)
 401 #define TCP_REASS_LOCK_CHECK(tp)                                        \
 402 do {                                                                    \
 403         if (((tp)->t_flags & TF_REASSEMBLING) == 0) {                   \
 404                 printf("%s:%d: tcpcb %p reass lock not held\n",         \
 405                     __FILE__, __LINE__, tp);                            \
 406                 panic("tcp reass lock check");                          \
 407         }                                                               \
 408 } while (/*CONSTCOND*/ 0)
 409 #else
 410 #define TCP_REASS_LOCK(tp)      (void) tcp_reass_lock_try((tp))
 411 #define TCP_REASS_LOCK_CHECK(tp) /* nothing */
 412 #endif
 413
 414 #define TCP_REASS_UNLOCK(tp)    tcp_reass_unlock((tp))
 415 #endif /* _KERNEL */
 416
 417 /*
 418  * Queue for delayed ACK processing.
 419  */
 420 #ifdef _KERNEL
 421 extern int tcp_delack_ticks;
 422 void    tcp_delack(void *);
 423
 424 #define TCP_RESTART_DELACK(tp)                                          \
 425         callout_reset(&(tp)->t_delack_ch, tcp_delack_ticks,             \
 426             tcp_delack, tp)
 427
 428 #define TCP_SET_DELACK(tp)                                              \
 429 do {                                                                    \
 430         if (((tp)->t_flags & TF_DELACK) == 0) {                         \
 431                 (tp)->t_flags |= TF_DELACK;                             \
 432                 TCP_RESTART_DELACK(tp);                                 \
 433         }                                                               \
 434 } while (/*CONSTCOND*/0)
 435
 436 #define TCP_CLEAR_DELACK(tp)                                            \
 437 do {                                                                    \
 438         if ((tp)->t_flags & TF_DELACK) {                                \
 439                 (tp)->t_flags &= ~TF_DELACK;                            \
 440                 callout_stop(&(tp)->t_delack_ch);                       \
 441         }                                                               \
 442 } while (/*CONSTCOND*/0)
 443 #endif /* _KERNEL */
 444
 445 /*
 446  * Compute the current timestamp for a connection.
 447  */
 448 #define TCP_TIMESTAMP(tp)       (tcp_now - (tp)->ts_timebase)
 449
 450 /*
 451  * Handy way of passing around TCP option info.
 452  */
 453 struct tcp_opt_info {
 454         int             ts_present;
 455         u_int32_t       ts_val;
 456         u_int32_t       ts_ecr;
 457         u_int16_t       maxseg;
 458 };
 459
 460 #define TOF_SIGNATURE   0x0040          /* signature option present */
 461 #define TOF_SIGLEN      0x0080          /* sigature length valid (RFC2385) */
 462
 463 /*
 464  * Data for the TCP compressed state engine.
 465  */
 466 union syn_cache_sa {
 467         struct sockaddr sa;
 468         struct sockaddr_in sin;
 469 #if 1 /*def INET6*/
 470         struct sockaddr_in6 sin6;
 471 #endif
 472 };
 473
 474 struct syn_cache {
 475         TAILQ_ENTRY(syn_cache) sc_bucketq;      /* link on bucket list */
 476         callout_t sc_timer;                     /* rexmt timer */
 477         struct route sc_route;
 478         long sc_win;                            /* advertised window */
 479         int sc_bucketidx;                       /* our bucket index */
 480         u_int32_t sc_hash;
 481         u_int32_t sc_timestamp;                 /* timestamp from SYN */
 482         u_int32_t sc_timebase;                  /* our local timebase */
 483         union syn_cache_sa sc_src;
 484         union syn_cache_sa sc_dst;
 485         tcp_seq sc_irs;
 486         tcp_seq sc_iss;
 487         u_int sc_rxtcur;                        /* current rxt timeout */
 488         u_int sc_rxttot;                        /* total time spend on queues */
 489         u_short sc_rxtshift;                    /* for computing backoff */
 490         u_short sc_flags;
 491
 492 #define SCF_UNREACH             0x0001          /* we've had an unreach error */
 493 #define SCF_TIMESTAMP           0x0002          /* peer will do timestamps */
 494 #define SCF_DEAD                0x0004          /* this entry to be released */
 495 #define SCF_SACK_PERMIT         0x0008          /* peer will do SACK */
 496 #define SCF_ECN_PERMIT          0x0010          /* peer will do ECN */
 497 #define SCF_SIGNATURE   0x40                    /* send MD5 digests */
 498
 499         struct mbuf *sc_ipopts;                 /* IP options */
 500         u_int16_t sc_peermaxseg;
 501         u_int16_t sc_ourmaxseg;
 502         u_int8_t sc_request_r_scale     : 4,
 503                  sc_requested_s_scale   : 4;
 504
 505         struct tcpcb *sc_tp;                    /* tcb for listening socket */
 506         LIST_ENTRY(syn_cache) sc_tpq;           /* list of entries by same tp */
 507 };
 508
 509 struct syn_cache_head {
 510         TAILQ_HEAD(, syn_cache) sch_bucket;     /* bucket entries */
 511         u_short sch_length;                     /* # entries in bucket */
 512 };
 513
 514 #define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
 515 #ifdef INET6
 516 #define in6totcpcb(ip)  ((struct tcpcb *)(ip)->in6p_ppcb)
 517 #endif
 518 #ifndef INET6
 519 #define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
 520 #else
 521 #define sototcpcb(so)   (((so)->so_proto->pr_domain->dom_family == AF_INET) \
 522                                 ? intotcpcb(sotoinpcb(so)) \
 523                                 : in6totcpcb(sotoin6pcb(so)))
 524 #endif
 525
 526 /*
 527  * The smoothed round-trip time and estimated variance
 528  * are stored as fixed point numbers scaled by the values below.
 529  * For convenience, these scales are also used in smoothing the average
 530  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 531  * With these scales, srtt has 3 bits to the right of the binary point,
 532  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 533  * binary point, and is smoothed with an ALPHA of 0.75.
 534  */
 535 #define TCP_RTT_SHIFT           3       /* shift for srtt; 3 bits frac. */
 536 #define TCP_RTTVAR_SHIFT        2       /* multiplier for rttvar; 2 bits */
 537
 538 /*
 539  * The initial retransmission should happen at rtt + 4 * rttvar.
 540  * Because of the way we do the smoothing, srtt and rttvar
 541  * will each average +1/2 tick of bias.  When we compute
 542  * the retransmit timer, we want 1/2 tick of rounding and
 543  * 1 extra tick because of +-1/2 tick uncertainty in the
 544  * firing of the timer.  The bias will give us exactly the
 545  * 1.5 tick we need.  But, because the bias is
 546  * statistical, we have to test that we don't drop below
 547  * the minimum feasible timer (which is 2 ticks).
 548  * This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT
 549  * is the same as the multiplier for rttvar.
 550  */
 551 #define TCP_REXMTVAL(tp) \
 552         ((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2)
 553
 554 /*
 555  * Compute the initial window for slow start.
 556  */
 557 #define TCP_INITIAL_WINDOW(iw, segsz) \
 558         (((iw) == 0) ? (min(4 * (segsz), max(2 * (segsz), 4380))) : \
 559          ((segsz) * (iw)))
 560
 561 /*
 562  * TCP statistics.
 563  * Each counter is an unsigned 64-bit value.
 564  *
 565  * Many of these should be kept per connection, but that's inconvenient
 566  * at the moment.
 567  */
 568 #define TCP_STAT_CONNATTEMPT    0       /* connections initiated */
 569 #define TCP_STAT_ACCEPTS        1       /* connections accepted */
 570 #define TCP_STAT_CONNECTS       2       /* connections established */
 571 #define TCP_STAT_DROPS          3       /* connections dropped */
 572 #define TCP_STAT_CONNDROPS      4       /* embryonic connections dropped */
 573 #define TCP_STAT_CLOSED         5       /* conn. closed (includes drops) */
 574 #define TCP_STAT_SEGSTIMED      6       /* segs where we tried to get rtt */
 575 #define TCP_STAT_RTTUPDATED     7       /* times we succeeded */
 576 #define TCP_STAT_DELACK         8       /* delayed ACKs sent */
 577 #define TCP_STAT_TIMEOUTDROP    9       /* conn. dropped in rxmt timeout */
 578 #define TCP_STAT_REXMTTIMEO     10      /* retransmit timeouts */
 579 #define TCP_STAT_PERSISTTIMEO   11      /* persist timeouts */
 580 #define TCP_STAT_KEEPTIMEO      12      /* keepalive timeouts */
 581 #define TCP_STAT_KEEPPROBE      13      /* keepalive probes sent */
 582 #define TCP_STAT_KEEPDROPS      14      /* connections dropped in keepalive */
 583 #define TCP_STAT_PERSISTDROPS   15      /* connections dropped in persist */
 584 #define TCP_STAT_CONNSDRAINED   16      /* connections drained due to memory
 585                                            shortage */
 586 #define TCP_STAT_PMTUBLACKHOLE  17      /* PMTUD blackhole detected */
 587 #define TCP_STAT_SNDTOTAL       18      /* total packets sent */
 588 #define TCP_STAT_SNDPACK        19      /* data packlets sent */
 589 #define TCP_STAT_SNDBYTE        20      /* data bytes sent */
 590 #define TCP_STAT_SNDREXMITPACK  21      /* data packets retransmitted */
 591 #define TCP_STAT_SNDREXMITBYTE  22      /* data bytes retransmitted */
 592 #define TCP_STAT_SNDACKS        23      /* ACK-only packets sent */
 593 #define TCP_STAT_SNDPROBE       24      /* window probes sent */
 594 #define TCP_STAT_SNDURG         25      /* packets sent with URG only */
 595 #define TCP_STAT_SNDWINUP       26      /* window update-only packets sent */
 596 #define TCP_STAT_SNDCTRL        27      /* control (SYN|FIN|RST) packets sent */
 597 #define TCP_STAT_RCVTOTAL       28      /* total packets received */
 598 #define TCP_STAT_RCVPACK        29      /* packets received in sequence */
 599 #define TCP_STAT_RCVBYTE        30      /* bytes received in sequence */
 600 #define TCP_STAT_RCVBADSUM      31      /* packets received with cksum errs */
 601 #define TCP_STAT_RCVBADOFF      32      /* packets received with bad offset */
 602 #define TCP_STAT_RCVMEMDROP     33      /* packets dropped for lack of memory */
 603 #define TCP_STAT_RCVSHORT       34      /* packets received too short */
 604 #define TCP_STAT_RCVDUPPACK     35      /* duplicate-only packets received */
 605 #define TCP_STAT_RCVDUPBYTE     36      /* duplicate-only bytes received */
 606 #define TCP_STAT_RCVPARTDUPPACK 37      /* packets with some duplicate data */
 607 #define TCP_STAT_RCVPARTDUPBYTE 38      /* dup. bytes in part-dup. packets */
 608 #define TCP_STAT_RCVOOPACK      39      /* out-of-order packets received */
 609 #define TCP_STAT_RCVOOBYTE      40      /* out-of-order bytes received */
 610 #define TCP_STAT_RCVPACKAFTERWIN 41     /* packets with data after window */
 611 #define TCP_STAT_RCVBYTEAFTERWIN 42     /* bytes received after window */
 612 #define TCP_STAT_RCVAFTERCLOSE  43      /* packets received after "close" */
 613 #define TCP_STAT_RCVWINPROBE    44      /* rcvd window probe packets */
 614 #define TCP_STAT_RCVDUPACK      45      /* rcvd duplicate ACKs */
 615 #define TCP_STAT_RCVACKTOOMUCH  46      /* rcvd ACKs for unsent data */
 616 #define TCP_STAT_RCVACKPACK     47      /* rcvd ACK packets */
 617 #define TCP_STAT_RCVACKBYTE     48      /* bytes ACKed by rcvd ACKs */
 618 #define TCP_STAT_RCVWINUPD      49      /* rcvd window update packets */
 619 #define TCP_STAT_PAWSDROP       50      /* segments dropped due to PAWS */
 620 #define TCP_STAT_PREDACK        51      /* times hdr predict OK for ACKs */
 621 #define TCP_STAT_PREDDAT        52      /* times hdr predict OK for data pkts */
 622 #define TCP_STAT_PCBHASHMISS    53      /* input packets missing PCB hash */
 623 #define TCP_STAT_NOPORT         54      /* no socket on port */
 624 #define TCP_STAT_BADSYN         55      /* received ACK for which we have
 625                                            no SYN in compressed state */
 626 #define TCP_STAT_DELAYED_FREE   56      /* delayed pool_put() of tcpcb */
 627 #define TCP_STAT_SC_ADDED       57      /* # of sc entries added */
 628 #define TCP_STAT_SC_COMPLETED   58      /* # of sc connections completed */
 629 #define TCP_STAT_SC_TIMED_OUT   59      /* # of sc entries timed out */
 630 #define TCP_STAT_SC_OVERFLOWED  60      /* # of sc drops due to overflow */
 631 #define TCP_STAT_SC_RESET       61      /* # of sc drops due to RST */
 632 #define TCP_STAT_SC_UNREACH     62      /* # of sc drops due to ICMP unreach */
 633 #define TCP_STAT_SC_BUCKETOVERFLOW 63   /* # of sc drops due to bucket ovflow */
 634 #define TCP_STAT_SC_ABORTED     64      /* # of sc entries aborted (no mem) */
 635 #define TCP_STAT_SC_DUPESYN     65      /* # of duplicate SYNs received */
 636 #define TCP_STAT_SC_DROPPED     66      /* # of SYNs dropped (no route/mem) */
 637 #define TCP_STAT_SC_COLLISIONS  67      /* # of sc hash collisions */
 638 #define TCP_STAT_SC_RETRANSMITTED 68    /* # of sc retransmissions */
 639 #define TCP_STAT_SC_DELAYED_FREE 69     /* # of delayed pool_put()s */
 640 #define TCP_STAT_SELFQUENCH     70      /* # of ENOBUFS we get on output */
 641 #define TCP_STAT_BADSIG         71      /* # of drops due to bad signature */
 642 #define TCP_STAT_GOODSIG        72      /* # of packets with good signature */
 643 #define TCP_STAT_ECN_SHS        73      /* # of successful ECN handshakes */
 644 #define TCP_STAT_ECN_CE         74      /* # of packets with CE bit */
 645 #define TCP_STAT_ECN_ECT        75      /* # of packets with ECT(0) bit */
 646
 647 #define TCP_NSTATS              76
 648
 649 /*
 650  * Names for TCP sysctl objects.
 651  */
 652 #define TCPCTL_RFC1323          1       /* RFC1323 timestamps/scaling */
 653 #define TCPCTL_SENDSPACE        2       /* default send buffer */
 654 #define TCPCTL_RECVSPACE        3       /* default recv buffer */
 655 #define TCPCTL_MSSDFLT          4       /* default seg size */
 656 #define TCPCTL_SYN_CACHE_LIMIT  5       /* max size of comp. state engine */
 657 #define TCPCTL_SYN_BUCKET_LIMIT 6       /* max size of hash bucket */
 658 #if 0   /*obsoleted*/
 659 #define TCPCTL_SYN_CACHE_INTER  7       /* interval of comp. state timer */
 660 #endif
 661 #define TCPCTL_INIT_WIN         8       /* initial window */
 662 #define TCPCTL_MSS_IFMTU        9       /* mss from interface, not in_maxmtu */
 663 #define TCPCTL_SACK             10      /* RFC2018 selective acknowledgement */
 664 #define TCPCTL_WSCALE           11      /* RFC1323 window scaling */
 665 #define TCPCTL_TSTAMP           12      /* RFC1323 timestamps */
 666 #define TCPCTL_COMPAT_42        13      /* 4.2BSD TCP bug work-arounds */
 667 #define TCPCTL_CWM              14      /* Congestion Window Monitoring */
 668 #define TCPCTL_CWM_BURSTSIZE    15      /* burst size allowed by CWM */
 669 #define TCPCTL_ACK_ON_PUSH      16      /* ACK immediately on PUSH */
 670 #define TCPCTL_KEEPIDLE         17      /* keepalive idle time */
 671 #define TCPCTL_KEEPINTVL        18      /* keepalive probe interval */
 672 #define TCPCTL_KEEPCNT          19      /* keepalive count */
 673 #define TCPCTL_SLOWHZ           20      /* PR_SLOWHZ (read-only) */
 674 #define TCPCTL_NEWRENO          21      /* NewReno Congestion Control */
 675 #define TCPCTL_LOG_REFUSED      22      /* Log refused connections */
 676 #if 0   /*obsoleted*/
 677 #define TCPCTL_RSTRATELIMIT     23      /* RST rate limit */
 678 #endif
 679 #define TCPCTL_RSTPPSLIMIT      24      /* RST pps limit */
 680 #define TCPCTL_DELACK_TICKS     25      /* # ticks to delay ACK */
 681 #define TCPCTL_INIT_WIN_LOCAL   26      /* initial window for local nets */
 682 #define TCPCTL_IDENT            27      /* rfc 931 identd */
 683 #define TCPCTL_ACKDROPRATELIMIT 28      /* SYN/RST -> ACK rate limit */
 684 #define TCPCTL_LOOPBACKCKSUM    29      /* do TCP checksum on loopback */
 685 #define TCPCTL_STATS            30      /* TCP statistics */
 686 #define TCPCTL_DEBUG            31      /* TCP debug sockets */
 687 #define TCPCTL_DEBX             32      /* # of tcp debug sockets */
 688 #define TCPCTL_DROP             33      /* drop tcp connection */
 689 #define TCPCTL_MSL              34      /* Max Segment Life */
 690 #define TCPCTL_MAXID            35
 691
 692 #define TCPCTL_NAMES { \
 693         { 0, 0 }, \
 694         { "rfc1323",    CTLTYPE_INT }, \
 695         { "sendspace",  CTLTYPE_INT }, \
 696         { "recvspace",  CTLTYPE_INT }, \
 697         { "mssdflt",    CTLTYPE_INT }, \
 698         { "syn_cache_limit", CTLTYPE_INT }, \
 699         { "syn_bucket_limit", CTLTYPE_INT }, \
 700         { 0, 0 },\
 701         { "init_win", CTLTYPE_INT }, \
 702         { "mss_ifmtu", CTLTYPE_INT }, \
 703         { "sack", CTLTYPE_INT }, \
 704         { "win_scale", CTLTYPE_INT }, \
 705         { "timestamps", CTLTYPE_INT }, \
 706         { "compat_42", CTLTYPE_INT }, \
 707         { "cwm", CTLTYPE_INT }, \
 708         { "cwm_burstsize", CTLTYPE_INT }, \
 709         { "ack_on_push", CTLTYPE_INT }, \
 710         { "keepidle",   CTLTYPE_INT }, \
 711         { "keepintvl",  CTLTYPE_INT }, \
 712         { "keepcnt",    CTLTYPE_INT }, \
 713         { "slowhz",     CTLTYPE_INT }, \
 714         { 0, 0 }, \
 715         { "log_refused",CTLTYPE_INT }, \
 716         { 0, 0 }, \
 717         { "rstppslimit", CTLTYPE_INT }, \
 718         { "delack_ticks", CTLTYPE_INT }, \
 719         { "init_win_local", CTLTYPE_INT }, \
 720         { "ident", CTLTYPE_STRUCT }, \
 721         { "ackdropppslimit", CTLTYPE_INT }, \
 722         { "do_loopback_cksum", CTLTYPE_INT }, \
 723         { "stats", CTLTYPE_STRUCT }, \
 724         { "debug", CTLTYPE_STRUCT }, \
 725         { "debx", CTLTYPE_INT }, \
 726         { "drop", CTLTYPE_STRUCT }, \
 727         { "msl", CTLTYPE_INT }, \
 728 }
 729
 730 #ifdef _KERNEL
 731 extern  struct inpcbtable tcbtable;     /* head of queue of active tcpcb's */
 732 extern  u_int32_t tcp_now;      /* for RFC 1323 timestamps */
 733 extern  int tcp_do_rfc1323;     /* enabled/disabled? */
 734 extern  int tcp_do_sack;        /* SACK enabled/disabled? */
 735 extern  int tcp_do_win_scale;   /* RFC1323 window scaling enabled/disabled? */
 736 extern  int tcp_do_timestamps;  /* RFC1323 timestamps enabled/disabled? */
 737 extern  int tcp_mssdflt;        /* default seg size */
 738 extern  int tcp_minmss;         /* minimal seg size */
 739 extern  int tcp_msl;            /* max segment life */
 740 extern  int tcp_init_win;       /* initial window */
 741 extern  int tcp_init_win_local; /* initial window for local nets */
 742 extern  int tcp_mss_ifmtu;      /* take MSS from interface, not in_maxmtu */
 743 extern  int tcp_compat_42;      /* work around ancient broken TCP peers */
 744 extern  int tcp_cwm;            /* enable Congestion Window Monitoring */
 745 extern  int tcp_cwm_burstsize;  /* burst size allowed by CWM */
 746 extern  int tcp_ack_on_push;    /* ACK immediately on PUSH */
 747 extern  int tcp_syn_cache_limit; /* max entries for compressed state engine */
 748 extern  int tcp_syn_bucket_limit;/* max entries per hash bucket */
 749 extern  int tcp_log_refused;    /* log refused connections */
 750 extern  int tcp_do_ecn;         /* TCP ECN enabled/disabled? */
 751 extern  int tcp_ecn_maxretries; /* Max ECN setup retries */
 752 #if NRND > 0
 753 extern  int tcp_do_rfc1948;     /* ISS by cryptographic hash */
 754 #endif
 755 extern int tcp_sack_tp_maxholes;        /* Max holes per connection. */
 756 extern int tcp_sack_globalmaxholes;     /* Max holes per system. */
 757 extern int tcp_sack_globalholes;        /* Number of holes present. */
 758 extern int tcp_do_abc;                  /* RFC3465 ABC enabled/disabled? */
 759 extern int tcp_abc_aggressive;          /* 1: L=2*SMSS  0: L=1*SMSS */
 760
 761 extern  int tcp_rst_ppslim;
 762 extern  int tcp_ackdrop_ppslim;
 763
 764 extern  int tcp_syn_cache_size;
 765 extern  struct syn_cache_head tcp_syn_cache[];
 766 extern  u_long syn_cache_count;
 767
 768 #ifdef MBUFTRACE
 769 extern  struct mowner tcp_rx_mowner;
 770 extern  struct mowner tcp_tx_mowner;
 771 extern  struct mowner tcp_reass_mowner;
 772 extern  struct mowner tcp_sock_mowner;
 773 extern  struct mowner tcp_sock_rx_mowner;
 774 extern  struct mowner tcp_sock_tx_mowner;
 775 extern  struct mowner tcp_mowner;
 776 #endif
 777
 778 extern int tcp_do_autorcvbuf;
 779 extern int tcp_autorcvbuf_inc;
 780 extern int tcp_autorcvbuf_max;
 781 extern int tcp_do_autosndbuf;
 782 extern int tcp_autosndbuf_inc;
 783 extern int tcp_autosndbuf_max;
 784
 785
 786 #define TCPCTL_VARIABLES { \
 787         { 0 },                                  \
 788         { 1, 0, &tcp_do_rfc1323 },              \
 789         { 1, 0, &tcp_sendspace },               \
 790         { 1, 0, &tcp_recvspace },               \
 791         { 1, 0, &tcp_mssdflt },                 \
 792         { 1, 0, &tcp_syn_cache_limit },         \
 793         { 1, 0, &tcp_syn_bucket_limit },        \
 794         { 0 },                                  \
 795         { 1, 0, &tcp_init_win },                \
 796         { 1, 0, &tcp_mss_ifmtu },               \
 797         { 1, 0, &tcp_do_sack },                 \
 798         { 1, 0, &tcp_do_win_scale },            \
 799         { 1, 0, &tcp_do_timestamps },           \
 800         { 1, 0, &tcp_compat_42 },               \
 801         { 1, 0, &tcp_cwm },                     \
 802         { 1, 0, &tcp_cwm_burstsize },           \
 803         { 1, 0, &tcp_ack_on_push },             \
 804         { 1, 0, &tcp_keepidle },                \
 805         { 1, 0, &tcp_keepintvl },               \
 806         { 1, 0, &tcp_keepcnt },                 \
 807         { 1, 1, 0, PR_SLOWHZ },                 \
 808         { 0 },                                  \
 809         { 1, 0, &tcp_log_refused },             \
 810         { 0 },                                  \
 811         { 1, 0, &tcp_rst_ppslim },              \
 812         { 1, 0, &tcp_delack_ticks },            \
 813         { 1, 0, &tcp_init_win_local },          \
 814         { 1, 0, &tcp_ackdrop_ppslim },          \
 815 }
 816
 817 struct secasvar;
 818
 819 int      tcp_attach(struct socket *);
 820 void     tcp_canceltimers(struct tcpcb *);
 821 struct tcpcb *
 822          tcp_close(struct tcpcb *);
 823 int      tcp_isdead(struct tcpcb *);
 824 #ifdef INET6
 825 void     *tcp6_ctlinput(int, const struct sockaddr *, void *);
 826 #endif
 827 void     *tcp_ctlinput(int, const struct sockaddr *, void *);
 828 int      tcp_ctloutput(int, struct socket *, struct sockopt *);
 829 struct tcpcb *
 830          tcp_disconnect(struct tcpcb *);
 831 struct tcpcb *
 832          tcp_drop(struct tcpcb *, int);
 833 #ifdef TCP_SIGNATURE
 834 int      tcp_signature_apply(void *, void *, u_int);
 835 struct secasvar *tcp_signature_getsav(struct mbuf *, struct tcphdr *);
 836 int      tcp_signature(struct mbuf *, struct tcphdr *, int, struct secasvar *,
 837             char *);
 838 #endif
 839 void     tcp_drain(void);
 840 void     tcp_established(struct tcpcb *);
 841 void     tcp_init(void);
 842 #ifdef INET6
 843 int      tcp6_input(struct mbuf **, int *, int);
 844 #endif
 845 void     tcp_input(struct mbuf *, ...);
 846 u_int    tcp_hdrsz(struct tcpcb *);
 847 u_long   tcp_mss_to_advertise(const struct ifnet *, int);
 848 void     tcp_mss_from_peer(struct tcpcb *, int);
 849 void     tcp_tcpcb_template(void);
 850 struct tcpcb *
 851          tcp_newtcpcb(int, void *);
 852 void     tcp_notify(struct inpcb *, int);
 853 #ifdef INET6
 854 void     tcp6_notify(struct in6pcb *, int);
 855 #endif
 856 u_int    tcp_optlen(struct tcpcb *);
 857 int      tcp_output(struct tcpcb *);
 858 void     tcp_pulloutofband(struct socket *,
 859             struct tcphdr *, struct mbuf *, int);
 860 void     tcp_quench(struct inpcb *, int);
 861 #ifdef INET6
 862 void     tcp6_quench(struct in6pcb *, int);
 863 #endif
 864 void     tcp_mtudisc(struct inpcb *, int);
 865
 866 void    tcpipqent_init(void);
 867 struct ipqent *tcpipqent_alloc(void);
 868 void     tcpipqent_free(struct ipqent *);
 869
 870 int      tcp_respond(struct tcpcb *, struct mbuf *, struct mbuf *,
 871             struct tcphdr *, tcp_seq, tcp_seq, int);
 872 void     tcp_rmx_rtt(struct tcpcb *);
 873 void     tcp_setpersist(struct tcpcb *);
 874 #ifdef TCP_SIGNATURE
 875 int      tcp_signature_compute(struct mbuf *, struct tcphdr *, int, int,
 876             int, u_char *, u_int);
 877 #endif
 878 void     tcp_slowtimo(void);
 879 struct mbuf *
 880          tcp_template(struct tcpcb *);
 881 void     tcp_trace(short, short, struct tcpcb *, struct mbuf *, int);
 882 struct tcpcb *
 883          tcp_usrclosed(struct tcpcb *);
 884 void     tcp_usrreq_init(void);
 885 int      tcp_usrreq(struct socket *,
 886             int, struct mbuf *, struct mbuf *, struct mbuf *, struct lwp *);
 887 void     tcp_xmit_timer(struct tcpcb *, uint32_t);
 888 tcp_seq  tcp_new_iss(struct tcpcb *, tcp_seq);
 889 tcp_seq  tcp_new_iss1(void *, void *, u_int16_t, u_int16_t, size_t,
 890             tcp_seq);
 891
 892 void     tcp_sack_init(void);
 893 void     tcp_new_dsack(struct tcpcb *, tcp_seq, u_int32_t);
 894 void     tcp_sack_option(struct tcpcb *, const struct tcphdr *,
 895             const u_char *, int);
 896 void     tcp_del_sackholes(struct tcpcb *, const struct tcphdr *);
 897 void     tcp_free_sackholes(struct tcpcb *);
 898 void     tcp_sack_adjust(struct tcpcb *tp);
 899 struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
 900 void     tcp_sack_newack(struct tcpcb *, const struct tcphdr *);
 901 int      tcp_sack_numblks(const struct tcpcb *);
 902 #define TCP_SACK_OPTLEN(nblks)  ((nblks) * 8 + 2 + 2)
 903
 904 void     tcp_statinc(u_int);
 905 void     tcp_statadd(u_int, uint64_t);
 906
 907 int      syn_cache_add(struct sockaddr *, struct sockaddr *,
 908                 struct tcphdr *, unsigned int, struct socket *,
 909                 struct mbuf *, u_char *, int, struct tcp_opt_info *);
 910 void     syn_cache_unreach(const struct sockaddr *, const struct sockaddr *,
 911            struct tcphdr *);
 912 struct socket *syn_cache_get(struct sockaddr *, struct sockaddr *,
 913                 struct tcphdr *, unsigned int, unsigned int,
 914                 struct socket *so, struct mbuf *);
 915 void     syn_cache_init(void);
 916 void     syn_cache_insert(struct syn_cache *, struct tcpcb *);
 917 struct syn_cache *syn_cache_lookup(const struct sockaddr *, const struct sockaddr *,
 918                 struct syn_cache_head **);
 919 void     syn_cache_reset(struct sockaddr *, struct sockaddr *,
 920                 struct tcphdr *);
 921 int      syn_cache_respond(struct syn_cache *, struct mbuf *);
 922 void     syn_cache_timer(void *);
 923 void     syn_cache_cleanup(struct tcpcb *);
 924
 925 int      tcp_input_checksum(int, struct mbuf *, const struct tcphdr *, int, int,
 926     int);
 927 #endif
 928
 929 #endif /* !_NETINET_TCP_VAR_H_ */