sys/netinet/tcp_var.h

   1 /*
   2  * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
   3  * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to The DragonFly Project
   6  * by Jeffrey M. Hsu.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of The DragonFly Project nor the names of its
  17  *    contributors may be used to endorse or promote products derived
  18  *    from this software without specific, prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  24  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Copyright (c) 1982, 1986, 1993, 1994, 1995
  36  *      The Regents of the University of California.  All rights reserved.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. All advertising materials mentioning features or use of this software
  47  *    must display the following acknowledgement:
  48  *      This product includes software developed by the University of
  49  *      California, Berkeley and its contributors.
  50  * 4. Neither the name of the University 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  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  64  * SUCH DAMAGE.
  65  *
  66  *      @(#)tcp_var.h   8.4 (Berkeley) 5/24/95
  67  * $FreeBSD: src/sys/netinet/tcp_var.h,v 1.56.2.13 2003/02/03 02:34:07 hsu Exp $
  68  * $DragonFly: src/sys/netinet/tcp_var.h,v 1.41 2008/08/15 21:37:16 nth Exp $
  69  */
  70
  71 #ifndef _NETINET_TCP_VAR_H_
  72 #define _NETINET_TCP_VAR_H_
  73
  74 #ifndef _NETINET_IN_PCB_H_
  75 #include <netinet/in_pcb.h>             /* needed for in_conninfo, inp_gen_t */
  76 #endif
  77 #ifndef _NETINET_TCP_H_
  78 #include <netinet/tcp.h>
  79 #endif
  80
  81 /*
  82  * Kernel variables for tcp.
  83  */
  84 extern int tcp_do_rfc1323;
  85 extern int tcp_do_rfc1644;
  86 extern int tcp_do_rfc3390;
  87 extern int tcp_do_sack;
  88 extern int tcp_do_smartsack;
  89 extern int tcp_aggregate_acks;
  90
  91 /* TCP segment queue entry */
  92 struct tseg_qent {
  93         LIST_ENTRY(tseg_qent) tqe_q;
  94         int     tqe_len;                /* TCP segment data length */
  95         struct  tcphdr *tqe_th;         /* a pointer to tcp header */
  96         struct  mbuf    *tqe_m;         /* mbuf contains packet */
  97 };
  98 LIST_HEAD(tsegqe_head, tseg_qent);
  99 extern int      tcp_reass_maxseg;
 100 extern int      tcp_reass_qsize;
 101 #ifdef MALLOC_DECLARE
 102 MALLOC_DECLARE(M_TSEGQ);
 103 #endif
 104
 105 struct tcptemp {
 106         u_char  tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
 107         struct  tcphdr tt_t;
 108 };
 109
 110 #define tcp6cb          tcpcb  /* for KAME src sync over BSD*'s */
 111
 112 struct raw_sackblock {                          /* covers [start, end) */
 113         tcp_seq rblk_start;
 114         tcp_seq rblk_end;
 115 };
 116
 117 /* maximum number of SACK blocks that will fit in the TCP option space */
 118 #define MAX_SACK_REPORT_BLOCKS  4
 119
 120 TAILQ_HEAD(sackblock_list, sackblock);
 121
 122 struct scoreboard {
 123         int nblocks;
 124         struct sackblock_list sackblocks;
 125         tcp_seq lostseq;                        /* passed SACK lost test */
 126         struct sackblock *lastfound;            /* search hint */
 127 };
 128
 129 /*
 130  * Tcp control block, one per tcp; fields:
 131  * Organized for 16 byte cacheline efficiency.
 132  */
 133 struct tcpcb {
 134         struct  tsegqe_head t_segq;
 135         int     t_dupacks;              /* consecutive dup acks recd */
 136         int     tt_cpu;                 /* sanity check the cpu */
 137         struct  callout *tt_rexmt;      /* retransmit timer */
 138
 139         struct  callout *tt_persist;    /* retransmit persistence */
 140         struct  callout *tt_keep;       /* keepalive */
 141         struct  callout *tt_2msl;       /* 2*msl TIME_WAIT timer */
 142         struct  callout *tt_delack;     /* delayed ACK timer */
 143
 144         struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
 145         int     t_state;                /* state of this connection */
 146         u_int   t_flags;
 147 #define TF_ACKNOW       0x00000001      /* ack peer immediately */
 148 #define TF_DELACK       0x00000002      /* ack, but try to delay it */
 149 #define TF_NODELAY      0x00000004      /* don't delay packets to coalesce */
 150 #define TF_NOOPT        0x00000008      /* don't use tcp options */
 151 #define TF_SENTFIN      0x00000010      /* have sent FIN */
 152 #define TF_REQ_SCALE    0x00000020      /* have/will request window scaling */
 153 #define TF_RCVD_SCALE   0x00000040      /* other side has requested scaling */
 154 #define TF_REQ_TSTMP    0x00000080      /* have/will request timestamps */
 155 #define TF_RCVD_TSTMP   0x00000100      /* a timestamp was received in SYN */
 156 #define TF_SACK_PERMITTED 0x00000200    /* other side said I could SACK */
 157 #define TF_NEEDSYN      0x00000400      /* send SYN (implicit state) */
 158 #define TF_NEEDFIN      0x00000800      /* send FIN (implicit state) */
 159 #define TF_NOPUSH       0x00001000      /* don't push */
 160 #define TF_REQ_CC       0x00002000      /* have/will request CC */
 161 #define TF_RCVD_CC      0x00004000      /* a CC was received in SYN */
 162 #define TF_SENDCCNEW    0x00008000      /* send CCnew instead of CC in SYN */
 163 #define TF_MORETOCOME   0x00010000      /* More data to be appended to sock */
 164 #define TF_LQ_OVERFLOW  0x00020000      /* listen queue overflow */
 165 #define TF_LASTIDLE     0x00040000      /* connection was previously idle */
 166 #define TF_RXWIN0SENT   0x00080000      /* sent a receiver win 0 in response */
 167 #define TF_FASTRECOVERY 0x00100000      /* in NewReno Fast Recovery */
 168 #define TF_WASFRECOVERY 0x00200000      /* was in NewReno Fast Recovery */
 169 #define TF_FIRSTACCACK  0x00400000      /* Look for 1st acceptable ACK. */
 170 #define TF_FASTREXMT    0x00800000      /* Did Fast Retransmit. */
 171 #define TF_EARLYREXMT   0x01000000      /* Did Early (Fast) Retransmit. */
 172 #define TF_FORCE        0x02000000      /* Set if forcing out a byte */
 173 #define TF_ONOUTPUTQ    0x04000000      /* on t_outputq list */
 174 #define TF_DUPSEG       0x08000000      /* last seg a duplicate */
 175 #define TF_ENCLOSESEG   0x10000000      /* enclosing SACK block */
 176 #define TF_SACKLEFT     0x20000000      /* send SACK blocks from left side */
 177         tcp_seq snd_up;                 /* send urgent pointer */
 178
 179         tcp_seq snd_una;                /* send unacknowledged */
 180         tcp_seq snd_recover;            /* for use with NewReno Fast Recovery */
 181         tcp_seq snd_max;                /* highest sequence number sent;
 182                                          * used to recognize retransmits */
 183         tcp_seq snd_nxt;                /* send next */
 184
 185         tcp_seq snd_wl1;                /* window update seg seq number */
 186         tcp_seq snd_wl2;                /* window update seg ack number */
 187         tcp_seq iss;                    /* initial send sequence number */
 188         tcp_seq irs;                    /* initial receive sequence number */
 189
 190         tcp_seq rcv_nxt;                /* receive next */
 191         tcp_seq rcv_adv;                /* advertised window */
 192         u_long  rcv_wnd;                /* receive window */
 193         tcp_seq rcv_up;                 /* receive urgent pointer */
 194
 195         u_long  snd_wnd;                /* send window */
 196         u_long  snd_cwnd;               /* congestion-controlled window */
 197         u_long  snd_wacked;             /* bytes acked in one send window */
 198         u_long  snd_ssthresh;           /* snd_cwnd size threshold for
 199                                          * for slow start exponential to
 200                                          * linear switch */
 201
 202         int     t_rxtcur;               /* current retransmit value (ticks) */
 203         u_int   t_maxseg;               /* maximum segment size */
 204         int     t_srtt;                 /* smoothed round-trip time */
 205         int     t_rttvar;               /* variance in round-trip time */
 206
 207         u_int   t_maxopd;               /* mss plus options */
 208
 209         u_long  t_rcvtime;              /* inactivity time */
 210         u_long  t_starttime;            /* time connection was established */
 211         int     t_rtttime;              /* round trip time */
 212         tcp_seq t_rtseq;                /* sequence number being timed */
 213
 214         int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
 215         u_int   t_rttmin;               /* minimum rtt allowed */
 216         u_int   t_rttbest;              /* best rtt we've seen */
 217         u_long  t_rttupdated;           /* number of times rtt sampled */
 218         u_long  max_sndwnd;             /* largest window peer has offered */
 219
 220         int     t_softerror;            /* possible error not yet reported */
 221 /* out-of-band data */
 222         char    t_oobflags;             /* have some */
 223         char    t_iobc;                 /* input character */
 224 #define TCPOOB_HAVEDATA 0x01
 225 #define TCPOOB_HADDATA  0x02
 226
 227 /* RFC 1323 variables */
 228         u_char  snd_scale;              /* window scaling for send window */
 229         u_char  rcv_scale;              /* window scaling for recv window */
 230         u_char  request_r_scale;        /* pending window scaling */
 231         u_char  requested_s_scale;
 232         u_long  ts_recent;              /* timestamp echo data */
 233
 234         u_long  ts_recent_age;          /* when last updated */
 235         tcp_seq last_ack_sent;
 236
 237 /* RFC 1644 variables */
 238         tcp_cc  cc_send;                /* send connection count */
 239         tcp_cc  cc_recv;                /* receive connection count */
 240
 241 /* experimental */
 242         u_long  snd_cwnd_prev;          /* cwnd prior to retransmit */
 243         u_long  snd_wacked_prev;        /* prior bytes acked in send window */
 244         u_long  snd_ssthresh_prev;      /* ssthresh prior to retransmit */
 245         tcp_seq snd_recover_prev;       /* snd_recover prior to retransmit */
 246         u_long  t_badrxtwin;            /* window for retransmit recovery */
 247         u_long  t_rexmtTS;              /* timestamp of last retransmit */
 248         u_char  snd_limited;            /* segments limited transmitted */
 249
 250         tcp_seq rexmt_high;             /* highest seq # retransmitted + 1 */
 251         tcp_seq snd_max_rexmt;          /* snd_max when rexmting snd_una */
 252         struct scoreboard scb;          /* sack scoreboard */
 253         struct raw_sackblock reportblk; /* incoming segment or D-SACK block */
 254         struct raw_sackblock encloseblk;
 255         int     nsackhistory;
 256         struct raw_sackblock sackhistory[MAX_SACK_REPORT_BLOCKS]; /* reported */
 257         TAILQ_ENTRY(tcpcb) t_outputq;   /* tcp_output needed list */
 258
 259         /* bandwith limitation */
 260         u_long  snd_bandwidth;          /* calculated bandwidth or 0 */
 261         u_long  snd_bwnd;               /* bandwidth-controlled window */
 262         int     t_bw_rtttime;           /* used for bandwidth calculation */
 263         tcp_seq t_bw_rtseq;             /* used for bandwidth calculation */
 264 };
 265
 266 #define IN_FASTRECOVERY(tp)     (tp->t_flags & TF_FASTRECOVERY)
 267 #define ENTER_FASTRECOVERY(tp)  tp->t_flags |= TF_FASTRECOVERY
 268 #define EXIT_FASTRECOVERY(tp)   tp->t_flags &= ~TF_FASTRECOVERY
 269
 270 /*
 271  * TCP statistics.
 272  */
 273 struct tcp_stats {
 274         u_long  tcps_connattempt;       /* connections initiated */
 275         u_long  tcps_accepts;           /* connections accepted */
 276         u_long  tcps_connects;          /* connections established */
 277         u_long  tcps_drops;             /* connections dropped */
 278         u_long  tcps_conndrops;         /* embryonic connections dropped */
 279         u_long  tcps_closed;            /* conn. closed (includes drops) */
 280         u_long  tcps_segstimed;         /* segs where we tried to get rtt */
 281         u_long  tcps_rttupdated;        /* times we succeeded */
 282         u_long  tcps_delack;            /* delayed acks sent */
 283         u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
 284         u_long  tcps_rexmttimeo;        /* retransmit timeouts */
 285         u_long  tcps_persisttimeo;      /* persist timeouts */
 286         u_long  tcps_keeptimeo;         /* keepalive timeouts */
 287         u_long  tcps_keepprobe;         /* keepalive probes sent */
 288         u_long  tcps_keepdrops;         /* connections dropped in keepalive */
 289
 290         u_long  tcps_sndtotal;          /* total packets sent */
 291         u_long  tcps_sndpack;           /* data packets sent */
 292         u_long  tcps_sndbyte;           /* data bytes sent */
 293         u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
 294         u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
 295         u_long  tcps_sndfastrexmit;     /* Fast Retransmissions */
 296         u_long  tcps_sndearlyrexmit;    /* early Fast Retransmissions */
 297         u_long  tcps_sndlimited;        /* Limited Transmit packets */
 298         u_long  tcps_sndrtobad;         /* spurious RTO retransmissions */
 299         u_long  tcps_sndfastrexmitbad;  /* spurious Fast Retransmissions */
 300         u_long  tcps_sndearlyrexmitbad; /* spurious early Fast Retransmissions,
 301                                            a subset of tcps_sndfastrexmitbad */
 302         u_long  tcps_eifeldetected;     /* Eifel-detected spurious rexmits */
 303         u_long  tcps_rttcantdetect;     /* Eifel but not 1/2 RTT-detectable */
 304         u_long  tcps_rttdetected;       /* RTT-detected spurious RTO rexmits */
 305         u_long  tcps_sndacks;           /* ack-only packets sent */
 306         u_long  tcps_sndprobe;          /* window probes sent */
 307         u_long  tcps_sndurg;            /* packets sent with URG only */
 308         u_long  tcps_sndwinup;          /* window update-only packets sent */
 309         u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
 310         u_long  tcps_sndsackpack;       /* packets sent by SACK recovery alg */
 311         u_long  tcps_sndsackbyte;       /* bytes sent by SACK recovery */
 312         u_long  tcps_snduna3;           /* re-retransmit snd_una on 3 new seg */
 313         u_long  tcps_snduna1;           /* re-retransmit snd_una on 1 new seg */
 314
 315         u_long  tcps_rcvtotal;          /* total packets received */
 316         u_long  tcps_rcvpack;           /* packets received in sequence */
 317         u_long  tcps_rcvbyte;           /* bytes received in sequence */
 318         u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
 319         u_long  tcps_rcvbadoff;         /* packets received with bad offset */
 320         u_long  tcps_rcvmemdrop;        /* packets dropped for lack of memory */
 321         u_long  tcps_rcvshort;          /* packets received too short */
 322         u_long  tcps_rcvduppack;        /* duplicate-only packets received */
 323         u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
 324         u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
 325         u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
 326         u_long  tcps_rcvoopack;         /* out-of-order packets received */
 327         u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
 328         u_long  tcps_rcvpackafterwin;   /* packets with data after window */
 329         u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
 330         u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
 331         u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
 332         u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
 333         u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
 334         u_long  tcps_rcvackpack;        /* rcvd ack packets */
 335         u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
 336         u_long  tcps_rcvwinupd;         /* rcvd window update packets */
 337         u_long  tcps_pawsdrop;          /* segments dropped due to PAWS */
 338         u_long  tcps_predack;           /* times hdr predict ok for acks */
 339         u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
 340         u_long  tcps_pcbcachemiss;
 341         u_long  tcps_cachedrtt;         /* times cached RTT in route updated */
 342         u_long  tcps_cachedrttvar;      /* times cached rttvar updated */
 343         u_long  tcps_cachedssthresh;    /* times cached ssthresh updated */
 344         u_long  tcps_usedrtt;           /* times RTT initialized from route */
 345         u_long  tcps_usedrttvar;        /* times RTTVAR initialized from rt */
 346         u_long  tcps_usedssthresh;      /* times ssthresh initialized from rt*/
 347         u_long  tcps_persistdrop;       /* timeout in persist state */
 348         u_long  tcps_badsyn;            /* bogus SYN, e.g. premature ACK */
 349         u_long  tcps_mturesent;         /* resends due to MTU discovery */
 350         u_long  tcps_listendrop;        /* listen queue overflows */
 351
 352         u_long  tcps_sc_added;          /* entry added to syncache */
 353         u_long  tcps_sc_retransmitted;  /* syncache entry was retransmitted */
 354         u_long  tcps_sc_dupsyn;         /* duplicate SYN packet */
 355         u_long  tcps_sc_dropped;        /* could not reply to packet */
 356         u_long  tcps_sc_completed;      /* successful extraction of entry */
 357         u_long  tcps_sc_bucketoverflow; /* syncache per-bucket limit hit */
 358         u_long  tcps_sc_cacheoverflow;  /* syncache cache limit hit */
 359         u_long  tcps_sc_reset;          /* RST removed entry from syncache */
 360         u_long  tcps_sc_stale;          /* timed out or listen socket gone */
 361         u_long  tcps_sc_aborted;        /* syncache entry aborted */
 362         u_long  tcps_sc_badack;         /* removed due to bad ACK */
 363         u_long  tcps_sc_unreach;        /* ICMP unreachable received */
 364         u_long  tcps_sc_zonefail;       /* zalloc() failed */
 365         u_long  tcps_sc_sendcookie;     /* SYN cookie sent */
 366         u_long  tcps_sc_recvcookie;     /* SYN cookie received */
 367 };
 368
 369 #ifdef _KERNEL
 370
 371 #if defined(SMP)
 372 #define tcpstat tcpstats_percpu[mycpuid]
 373 #else
 374 #define tcpstat tcpstats_percpu[0]
 375 #endif
 376
 377 struct sockopt;
 378
 379 extern struct tcp_stats         tcpstats_percpu[MAXCPU];
 380
 381 static const int tcprexmtthresh = 3;
 382 #endif
 383
 384 /*
 385  * Structure to hold TCP options that are only used during segment
 386  * processing (in tcp_input), but not held in the tcpcb.
 387  * It's basically used to reduce the number of parameters
 388  * to tcp_dooptions.
 389  */
 390 struct tcpopt {
 391         u_long          to_flags;       /* which options are present */
 392 #define TOF_TS                  0x0001          /* timestamp */
 393 #define TOF_CC                  0x0002          /* CC and CCnew are exclusive */
 394 #define TOF_CCNEW               0x0004
 395 #define TOF_CCECHO              0x0008
 396 #define TOF_MSS                 0x0010
 397 #define TOF_SCALE               0x0020
 398 #define TOF_SACK_PERMITTED      0x0040
 399 #define TOF_SACK                0x0080
 400         u_int32_t       to_tsval;
 401         u_int32_t       to_tsecr;
 402         tcp_cc          to_cc;          /* holds CC or CCnew */
 403         tcp_cc          to_ccecho;
 404         u_int16_t       to_mss;
 405         u_int8_t        to_requested_s_scale;
 406         u_int8_t        to_nsackblocks;
 407         struct raw_sackblock *to_sackblocks;
 408 };
 409
 410 struct syncache {
 411         inp_gen_t       sc_inp_gencnt;          /* pointer check */
 412         struct          tcpcb *sc_tp;           /* tcb for listening socket */
 413         struct          mbuf *sc_ipopts;        /* source route */
 414         struct          in_conninfo sc_inc;     /* addresses */
 415 #define sc_route        sc_inc.inc_route
 416 #define sc_route6       sc_inc.inc6_route
 417         u_int32_t       sc_tsrecent;
 418         tcp_cc          sc_cc_send;             /* holds CC or CCnew */
 419         tcp_cc          sc_cc_recv;
 420         tcp_seq         sc_irs;                 /* seq from peer */
 421         tcp_seq         sc_iss;                 /* our ISS */
 422         u_long          sc_rxttime;             /* retransmit time */
 423         u_int16_t       sc_rxtslot;             /* retransmit counter */
 424         u_int16_t       sc_peer_mss;            /* peer's MSS */
 425         u_int16_t       sc_wnd;                 /* advertised window */
 426         u_int8_t        sc_requested_s_scale:4,
 427                         sc_request_r_scale:4;
 428         u_int8_t        sc_flags;
 429 #define SCF_NOOPT               0x01            /* no TCP options */
 430 #define SCF_WINSCALE            0x02            /* negotiated window scaling */
 431 #define SCF_TIMESTAMP           0x04            /* negotiated timestamps */
 432 #define SCF_CC                  0x08            /* negotiated CC */
 433 #define SCF_UNREACH             0x10            /* icmp unreachable received */
 434 #define SCF_SACK_PERMITTED      0x20            /* saw SACK permitted option */
 435         TAILQ_ENTRY(syncache) sc_hash;
 436         TAILQ_ENTRY(syncache) sc_timerq;
 437 };
 438
 439 struct syncache_head {
 440         TAILQ_HEAD(, syncache)  sch_bucket;
 441         u_int           sch_length;
 442 };
 443
 444 /*
 445  * The TAO cache entry which is stored in the protocol family specific
 446  * portion of the route metrics.
 447  */
 448 struct rmxp_tao {
 449         tcp_cc  tao_cc;                 /* latest CC in valid SYN */
 450         tcp_cc  tao_ccsent;             /* latest CC sent to peer */
 451         u_short tao_mssopt;             /* peer's cached MSS */
 452
 453 #ifdef notyet
 454         u_short tao_flags;              /* cache status flags */
 455 #define TAOF_DONT       0x0001          /* peer doesn't understand rfc1644 */
 456 #define TAOF_OK         0x0002          /* peer does understand rfc1644 */
 457 #define TAOF_UNDEF      0               /* we don't know yet */
 458 #endif
 459 };
 460
 461 #define rmx_taop(rt)    ((struct rmxp_tao *)(rt).rmx_filler)
 462
 463 #define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
 464 #define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
 465
 466 /*
 467  * The smoothed round-trip time and estimated variance
 468  * are stored as fixed point numbers scaled by the values below.
 469  * For convenience, these scales are also used in smoothing the average
 470  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 471  * With these scales, srtt has 3 bits to the right of the binary point,
 472  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 473  * binary point, and is smoothed with an ALPHA of 0.75.
 474  */
 475 #define TCP_RTT_SCALE           32      /* multiplier for srtt; 3 bits frac. */
 476 #define TCP_RTT_SHIFT           5       /* shift for srtt; 3 bits frac. */
 477 #define TCP_RTTVAR_SCALE        16      /* multiplier for rttvar; 2 bits */
 478 #define TCP_RTTVAR_SHIFT        4       /* shift for rttvar; 2 bits */
 479 #define TCP_DELTA_SHIFT         2       /* see tcp_input.c */
 480
 481 /*
 482  * The initial retransmission should happen at rtt + 4 * rttvar.
 483  * Because of the way we do the smoothing, srtt and rttvar
 484  * will each average +1/2 tick of bias.  When we compute
 485  * the retransmit timer, we want 1/2 tick of rounding and
 486  * 1 extra tick because of +-1/2 tick uncertainty in the
 487  * firing of the timer.  The bias will give us exactly the
 488  * 1.5 tick we need.  But, because the bias is
 489  * statistical, we have to test that we don't drop below
 490  * the minimum feasible timer (which is 2 ticks).
 491  * This version of the macro adapted from a paper by Lawrence
 492  * Brakmo and Larry Peterson which outlines a problem caused
 493  * by insufficient precision in the original implementation,
 494  * which results in inappropriately large RTO values for very
 495  * fast networks.
 496  */
 497 #define TCP_REXMTVAL(tp) \
 498         max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
 499           + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
 500
 501 /*
 502  * TCB structure exported to user-land via sysctl(3).
 503  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
 504  * included.  Not all of our clients do.
 505  */
 506 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
 507 struct  xtcpcb {
 508         size_t  xt_len;
 509         struct  inpcb   xt_inp;
 510         struct  tcpcb   xt_tp;
 511         struct  xsocket xt_socket;
 512         u_quad_t        xt_alignment_hack;
 513 };
 514 #endif
 515
 516 /*
 517  * Names for TCP sysctl objects
 518  */
 519 #define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
 520 #define TCPCTL_DO_RFC1644       2       /* use RFC-1644 extensions */
 521 #define TCPCTL_MSSDFLT          3       /* MSS default */
 522 #define TCPCTL_STATS            4       /* statistics (read-only) */
 523 #define TCPCTL_RTTDFLT          5       /* default RTT estimate */
 524 #define TCPCTL_KEEPIDLE         6       /* keepalive idle timer */
 525 #define TCPCTL_KEEPINTVL        7       /* interval to send keepalives */
 526 #define TCPCTL_SENDSPACE        8       /* send buffer space */
 527 #define TCPCTL_RECVSPACE        9       /* receive buffer space */
 528 #define TCPCTL_KEEPINIT         10      /* timeout for establishing syn */
 529 #define TCPCTL_PCBLIST          11      /* list of all outstanding PCBs */
 530 #define TCPCTL_DELACKTIME       12      /* time before sending delayed ACK */
 531 #define TCPCTL_V6MSSDFLT        13      /* MSS default for IPv6 */
 532 #define TCPCTL_MAXID            14
 533
 534 #define TCPCTL_NAMES { \
 535         { 0, 0 }, \
 536         { "rfc1323", CTLTYPE_INT }, \
 537         { "rfc1644", CTLTYPE_INT }, \
 538         { "mssdflt", CTLTYPE_INT }, \
 539         { "stats", CTLTYPE_STRUCT }, \
 540         { "rttdflt", CTLTYPE_INT }, \
 541         { "keepidle", CTLTYPE_INT }, \
 542         { "keepintvl", CTLTYPE_INT }, \
 543         { "sendspace", CTLTYPE_INT }, \
 544         { "recvspace", CTLTYPE_INT }, \
 545         { "keepinit", CTLTYPE_INT }, \
 546         { "pcblist", CTLTYPE_STRUCT }, \
 547         { "delacktime", CTLTYPE_INT }, \
 548         { "v6mssdflt", CTLTYPE_INT }, \
 549 }
 550
 551 #ifdef _KERNEL
 552 #ifdef SYSCTL_DECL
 553 SYSCTL_DECL(_net_inet_tcp);
 554 #endif
 555
 556 #define TCP_DO_SACK(tp)         ((tp)->t_flags & TF_SACK_PERMITTED)
 557
 558 TAILQ_HEAD(tcpcbackqhead,tcpcb);
 559
 560 extern  struct inpcbinfo tcbinfo[];
 561 extern  struct tcpcbackqhead tcpcbackq[];
 562
 563 extern  int tcp_mssdflt;        /* XXX */
 564 extern  int tcp_delack_enabled;
 565 extern  int path_mtu_discovery;
 566
 567 int      tcp_addrcpu(in_addr_t faddr, in_port_t fport,
 568             in_addr_t laddr, in_port_t lport);
 569 struct lwkt_port *
 570         tcp_addrport(in_addr_t faddr, in_port_t fport,
 571             in_addr_t laddr, in_port_t lport);
 572 void     tcp_canceltimers (struct tcpcb *);
 573 struct tcpcb *
 574          tcp_close (struct tcpcb *);
 575 void     tcpmsg_service_loop (void *);
 576 void     tcp_ctlinput (int, struct sockaddr *, void *);
 577 int      tcp_ctloutput (struct socket *, struct sockopt *);
 578 struct lwkt_port *
 579          tcp_cport(int cpu);
 580 struct tcpcb *
 581          tcp_drop (struct tcpcb *, int);
 582 void     tcp_drain (void);
 583 void     tcp_fasttimo (void);
 584 struct rmxp_tao *
 585          tcp_gettaocache (struct in_conninfo *);
 586 void     tcp_init (void);
 587 void     tcp_thread_init (void);
 588 void     tcp_input (struct mbuf *, ...);
 589 void     tcp_mss (struct tcpcb *, int);
 590 int      tcp_mssopt (struct tcpcb *);
 591 void     tcp_drop_syn_sent (struct inpcb *, int);
 592 void     tcp_mtudisc (struct inpcb *, int);
 593 struct tcpcb *
 594          tcp_newtcpcb (struct inpcb *);
 595 int      tcp_output (struct tcpcb *);
 596 void     tcp_quench (struct inpcb *, int);
 597 void     tcp_respond (struct tcpcb *, void *,
 598             struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
 599 struct rtentry *
 600          tcp_rtlookup (struct in_conninfo *);
 601 int      tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq);
 602 void     tcp_sack_cleanup(struct scoreboard *scb);
 603 int      tcp_sack_ndsack_blocks(struct raw_sackblock *blocks,
 604             const int numblocks, tcp_seq snd_una);
 605 void     tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen);
 606 boolean_t
 607          tcp_sack_has_sacked(struct scoreboard *scb, u_int amount);
 608 void     tcp_sack_tcpcb_init(struct tcpcb *tp);
 609 uint32_t tcp_sack_compute_pipe(struct tcpcb *tp);
 610 boolean_t
 611          tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *len,
 612                           boolean_t *losdup);
 613 #ifdef later
 614 void     tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una,
 615                                     u_int maxseg);
 616 void     tcp_sack_save_scoreboard(struct scoreboard *scb);
 617 #endif
 618 void     tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt);
 619 void     tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to);
 620 void     tcp_save_congestion_state(struct tcpcb *tp);
 621 void     tcp_revert_congestion_state(struct tcpcb *tp);
 622 void     tcp_setpersist (struct tcpcb *);
 623 void     tcp_slowtimo (void);
 624 struct tcptemp *tcp_maketemplate (struct tcpcb *);
 625 void     tcp_freetemplate (struct tcptemp *);
 626 void     tcp_fillheaders (struct tcpcb *, void *, void *);
 627 struct lwkt_port *
 628          tcp_soport(struct socket *, struct sockaddr *,
 629                     struct mbuf **, int);
 630 struct tcpcb *
 631          tcp_timers (struct tcpcb *, int);
 632 void     tcp_trace (short, short, struct tcpcb *, void *, struct tcphdr *,
 633                         int);
 634 void     tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
 635 void     syncache_init(void);
 636 void     syncache_unreach(struct in_conninfo *, struct tcphdr *);
 637 int      syncache_expand(struct in_conninfo *, struct tcphdr *,
 638              struct socket **, struct mbuf *);
 639 int      syncache_add(struct in_conninfo *, struct tcpopt *,
 640              struct tcphdr *, struct socket **, struct mbuf *);
 641 void     syncache_chkrst(struct in_conninfo *, struct tcphdr *);
 642 void     syncache_badack(struct in_conninfo *);
 643
 644 extern  struct pr_usrreqs tcp_usrreqs;
 645 extern  u_long tcp_sendspace;
 646 extern  u_long tcp_recvspace;
 647 tcp_seq tcp_new_isn (struct tcpcb *);
 648
 649 #endif /* _KERNEL */
 650
 651 #endif /* _NETINET_TCP_VAR_H_ */