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 1.42 2008/10/27 02:56:30 sephe 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_rfc3390;
  86 extern int tcp_do_sack;
  87 extern int tcp_do_smartsack;
  88 extern int tcp_aggregate_acks;
  89
  90 /* TCP segment queue entry */
  91 struct tseg_qent {
  92         LIST_ENTRY(tseg_qent) tqe_q;
  93         int     tqe_len;                /* TCP segment data length */
  94         struct  tcphdr *tqe_th;         /* a pointer to tcp header */
  95         struct  mbuf    *tqe_m;         /* mbuf contains packet */
  96 };
  97 LIST_HEAD(tsegqe_head, tseg_qent);
  98 extern int      tcp_reass_maxseg;
  99 extern int      tcp_reass_qsize;
 100 #ifdef MALLOC_DECLARE
 101 MALLOC_DECLARE(M_TSEGQ);
 102 #endif
 103
 104 struct tcptemp {
 105         u_char  tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
 106         struct  tcphdr tt_t;
 107 };
 108
 109 #define tcp6cb          tcpcb  /* for KAME src sync over BSD*'s */
 110
 111 struct raw_sackblock {                          /* covers [start, end) */
 112         tcp_seq rblk_start;
 113         tcp_seq rblk_end;
 114 };
 115
 116 /* maximum number of SACK blocks that will fit in the TCP option space */
 117 #define MAX_SACK_REPORT_BLOCKS  4
 118
 119 TAILQ_HEAD(sackblock_list, sackblock);
 120
 121 struct scoreboard {
 122         int nblocks;
 123         struct sackblock_list sackblocks;
 124         tcp_seq lostseq;                        /* passed SACK lost test */
 125         struct sackblock *lastfound;            /* search hint */
 126 };
 127
 128 struct netmsg_tcp_timer;
 129
 130 /*
 131  * Tcp control block, one per tcp; fields:
 132  * Organized for 16 byte cacheline efficiency.
 133  */
 134 struct tcpcb {
 135         struct  tsegqe_head t_segq;
 136         int     t_dupacks;              /* consecutive dup acks recd */
 137         int     tt_cpu;                 /* sanity check the cpu */
 138
 139         struct  tcp_callout *tt_rexmt;  /* retransmit timer */
 140         struct  tcp_callout *tt_persist;/* retransmit persistence */
 141         struct  tcp_callout *tt_keep;   /* keepalive */
 142         struct  tcp_callout *tt_2msl;   /* 2*msl TIME_WAIT timer */
 143         struct  tcp_callout *tt_delack; /* delayed ACK timer */
 144         struct  netmsg_tcp_timer *tt_msg; /* timer message */
 145
 146         struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
 147         int     t_state;                /* state of this connection */
 148         u_int   t_flags;
 149 #define TF_ACKNOW       0x00000001      /* ack peer immediately */
 150 #define TF_DELACK       0x00000002      /* ack, but try to delay it */
 151 #define TF_NODELAY      0x00000004      /* don't delay packets to coalesce */
 152 #define TF_NOOPT        0x00000008      /* don't use tcp options */
 153 #define TF_SENTFIN      0x00000010      /* have sent FIN */
 154 #define TF_REQ_SCALE    0x00000020      /* have/will request window scaling */
 155 #define TF_RCVD_SCALE   0x00000040      /* other side has requested scaling */
 156 #define TF_REQ_TSTMP    0x00000080      /* have/will request timestamps */
 157 #define TF_RCVD_TSTMP   0x00000100      /* a timestamp was received in SYN */
 158 #define TF_SACK_PERMITTED 0x00000200    /* other side said I could SACK */
 159 #define TF_NEEDSYN      0x00000400      /* send SYN (implicit state) */
 160 #define TF_NEEDFIN      0x00000800      /* send FIN (implicit state) */
 161 #define TF_NOPUSH       0x00001000      /* don't push */
 162 #define TF_SYNCACHE     0x00002000      /* syncache present */
 163 /* 0x00001000 - 0x00008000 were used for T/TCP */
 164 #define TF_MORETOCOME   0x00010000      /* More data to be appended to sock */
 165 #define TF_LQ_OVERFLOW  0x00020000      /* listen queue overflow */
 166 #define TF_LASTIDLE     0x00040000      /* connection was previously idle */
 167 #define TF_RXWIN0SENT   0x00080000      /* sent a receiver win 0 in response */
 168 #define TF_FASTRECOVERY 0x00100000      /* in NewReno Fast Recovery */
 169 #define TF_WASFRECOVERY 0x00200000      /* was in NewReno Fast Recovery */
 170 #define TF_FIRSTACCACK  0x00400000      /* Look for 1st acceptable ACK. */
 171 #define TF_FASTREXMT    0x00800000      /* Did Fast Retransmit. */
 172 #define TF_EARLYREXMT   0x01000000      /* Did Early (Fast) Retransmit. */
 173 #define TF_FORCE        0x02000000      /* Set if forcing out a byte */
 174 #define TF_ONOUTPUTQ    0x04000000      /* on t_outputq list */
 175 #define TF_DUPSEG       0x08000000      /* last seg a duplicate */
 176 #define TF_ENCLOSESEG   0x10000000      /* enclosing SACK block */
 177 #define TF_SACKLEFT     0x20000000      /* send SACK blocks from left side */
 178 #define TF_KEEPALIVE    0x40000000      /* temporary keepalive */
 179 #define TF_RXRESIZED    0x80000000      /* rcvbuf was resized */
 180         tcp_seq snd_up;                 /* send urgent pointer */
 181
 182         tcp_seq snd_una;                /* send unacknowledged */
 183         tcp_seq snd_recover;            /* for use with NewReno Fast Recovery */
 184         tcp_seq snd_max;                /* highest sequence number sent;
 185                                          * used to recognize retransmits */
 186         tcp_seq snd_nxt;                /* send next */
 187
 188         tcp_seq snd_wl1;                /* window update seg seq number */
 189         tcp_seq snd_wl2;                /* window update seg ack number */
 190         tcp_seq iss;                    /* initial send sequence number */
 191         tcp_seq irs;                    /* initial receive sequence number */
 192
 193         tcp_seq rcv_nxt;                /* receive next */
 194         tcp_seq rcv_adv;                /* advertised window */
 195         u_long  rcv_wnd;                /* receive window */
 196         tcp_seq rcv_up;                 /* receive urgent pointer */
 197
 198         u_long  snd_wnd;                /* send window */
 199         u_long  snd_cwnd;               /* congestion-controlled window */
 200         u_long  snd_wacked;             /* bytes acked in one send window */
 201         u_long  snd_ssthresh;           /* snd_cwnd size threshold for
 202                                          * for slow start exponential to
 203                                          * linear switch */
 204
 205         int     t_rxtcur;               /* current retransmit value (ticks) */
 206         u_int   t_maxseg;               /* maximum segment size */
 207         int     t_srtt;                 /* smoothed round-trip time */
 208         int     t_rttvar;               /* variance in round-trip time */
 209
 210         u_int   t_maxopd;               /* mss plus options */
 211
 212         u_long  t_rcvtime;              /* inactivity time */
 213         u_long  t_starttime;            /* time connection was established */
 214         int     t_rtttime;              /* round trip time */
 215         tcp_seq t_rtseq;                /* sequence number being timed */
 216
 217         int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
 218         u_int   t_rttmin;               /* minimum rtt allowed */
 219         u_int   t_rttbest;              /* best rtt we've seen */
 220         u_long  t_rttupdated;           /* number of times rtt sampled */
 221         u_long  max_sndwnd;             /* largest window peer has offered */
 222
 223         int     t_softerror;            /* possible error not yet reported */
 224 /* out-of-band data */
 225         char    t_oobflags;             /* have some */
 226         char    t_iobc;                 /* input character */
 227 #define TCPOOB_HAVEDATA 0x01
 228 #define TCPOOB_HADDATA  0x02
 229
 230 /* RFC 1323 variables */
 231         u_char  snd_scale;              /* window scaling for send window */
 232         u_char  rcv_scale;              /* window scaling for recv window */
 233         u_char  request_r_scale;        /* pending window scaling */
 234         u_char  requested_s_scale;
 235         u_long  ts_recent;              /* timestamp echo data */
 236
 237         u_long  ts_recent_age;          /* when last updated */
 238         tcp_seq last_ack_sent;
 239
 240 /* experimental */
 241         u_long  snd_cwnd_prev;          /* cwnd prior to retransmit */
 242         u_long  snd_wacked_prev;        /* prior bytes acked in send window */
 243         u_long  snd_ssthresh_prev;      /* ssthresh prior to retransmit */
 244         tcp_seq snd_recover_prev;       /* snd_recover prior to retransmit */
 245         u_long  t_badrxtwin;            /* window for retransmit recovery */
 246         u_long  t_rexmtTS;              /* timestamp of last retransmit */
 247         u_char  snd_limited;            /* segments limited transmitted */
 248
 249         tcp_seq rexmt_high;             /* highest seq # retransmitted + 1 */
 250         tcp_seq snd_max_rexmt;          /* snd_max when rexmting snd_una */
 251         struct scoreboard scb;          /* sack scoreboard */
 252         struct raw_sackblock reportblk; /* incoming segment or D-SACK block */
 253         struct raw_sackblock encloseblk;
 254         int     nsackhistory;
 255         struct raw_sackblock sackhistory[MAX_SACK_REPORT_BLOCKS]; /* reported */
 256         TAILQ_ENTRY(tcpcb) t_outputq;   /* tcp_output needed list */
 257
 258         /* bandwith limitation */
 259         u_long  snd_bandwidth;          /* calculated bandwidth or 0 */
 260         u_long  snd_bwnd;               /* bandwidth-controlled window */
 261         int     t_bw_rtttime;           /* used for bandwidth calculation */
 262         tcp_seq t_bw_rtseq;             /* used for bandwidth calculation */
 263
 264 /* anti DoS counters */
 265         u_long  rcv_second;             /* start of interval second */
 266         u_long  rcv_pps;                /* received packets per second */
 267         u_long  rcv_byps;               /* received bytes per second */
 268
 269         u_int32_t       rfbuf_ts;       /* recv buffer autoscaling timestamp */
 270         int     rfbuf_cnt;              /* recv buffer autoscaling byte count */
 271 };
 272
 273 #define IN_FASTRECOVERY(tp)     (tp->t_flags & TF_FASTRECOVERY)
 274 #define ENTER_FASTRECOVERY(tp)  tp->t_flags |= TF_FASTRECOVERY
 275 #define EXIT_FASTRECOVERY(tp)   tp->t_flags &= ~TF_FASTRECOVERY
 276
 277 /*
 278  * TCP statistics.
 279  */
 280 struct tcp_stats {
 281         u_long  tcps_connattempt;       /* connections initiated */
 282         u_long  tcps_accepts;           /* connections accepted */
 283         u_long  tcps_connects;          /* connections established */
 284         u_long  tcps_drops;             /* connections dropped */
 285         u_long  tcps_conndrops;         /* embryonic connections dropped */
 286         u_long  tcps_minmssdrops;       /* average minmss too low drops */
 287         u_long  tcps_closed;            /* conn. closed (includes drops) */
 288         u_long  tcps_segstimed;         /* segs where we tried to get rtt */
 289         u_long  tcps_rttupdated;        /* times we succeeded */
 290         u_long  tcps_delack;            /* delayed acks sent */
 291         u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
 292         u_long  tcps_rexmttimeo;        /* retransmit timeouts */
 293         u_long  tcps_persisttimeo;      /* persist timeouts */
 294         u_long  tcps_keeptimeo;         /* keepalive timeouts */
 295         u_long  tcps_keepprobe;         /* keepalive probes sent */
 296         u_long  tcps_keepdrops;         /* connections dropped in keepalive */
 297
 298         u_long  tcps_sndtotal;          /* total packets sent */
 299         u_long  tcps_sndpack;           /* data packets sent */
 300         u_long  tcps_sndbyte;           /* data bytes sent */
 301         u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
 302         u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
 303         u_long  tcps_sndfastrexmit;     /* Fast Retransmissions */
 304         u_long  tcps_sndearlyrexmit;    /* early Fast Retransmissions */
 305         u_long  tcps_sndlimited;        /* Limited Transmit packets */
 306         u_long  tcps_sndrtobad;         /* spurious RTO retransmissions */
 307         u_long  tcps_sndfastrexmitbad;  /* spurious Fast Retransmissions */
 308         u_long  tcps_sndearlyrexmitbad; /* spurious early Fast Retransmissions,
 309                                            a subset of tcps_sndfastrexmitbad */
 310         u_long  tcps_eifeldetected;     /* Eifel-detected spurious rexmits */
 311         u_long  tcps_rttcantdetect;     /* Eifel but not 1/2 RTT-detectable */
 312         u_long  tcps_rttdetected;       /* RTT-detected spurious RTO rexmits */
 313         u_long  tcps_sndacks;           /* ack-only packets sent */
 314         u_long  tcps_sndprobe;          /* window probes sent */
 315         u_long  tcps_sndurg;            /* packets sent with URG only */
 316         u_long  tcps_sndwinup;          /* window update-only packets sent */
 317         u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
 318         u_long  tcps_sndsackpack;       /* packets sent by SACK recovery alg */
 319         u_long  tcps_sndsackbyte;       /* bytes sent by SACK recovery */
 320         u_long  tcps_snduna3;           /* re-retransmit snd_una on 3 new seg */
 321         u_long  tcps_snduna1;           /* re-retransmit snd_una on 1 new seg */
 322
 323         u_long  tcps_rcvtotal;          /* total packets received */
 324         u_long  tcps_rcvpack;           /* packets received in sequence */
 325         u_long  tcps_rcvbyte;           /* bytes received in sequence */
 326         u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
 327         u_long  tcps_rcvbadoff;         /* packets received with bad offset */
 328         u_long  tcps_rcvmemdrop;        /* packets dropped for lack of memory */
 329         u_long  tcps_rcvshort;          /* packets received too short */
 330         u_long  tcps_rcvduppack;        /* duplicate-only packets received */
 331         u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
 332         u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
 333         u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
 334         u_long  tcps_rcvoopack;         /* out-of-order packets received */
 335         u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
 336         u_long  tcps_rcvpackafterwin;   /* packets with data after window */
 337         u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
 338         u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
 339         u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
 340         u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
 341         u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
 342         u_long  tcps_rcvackpack;        /* rcvd ack packets */
 343         u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
 344         u_long  tcps_rcvwinupd;         /* rcvd window update packets */
 345         u_long  tcps_pawsdrop;          /* segments dropped due to PAWS */
 346         u_long  tcps_predack;           /* times hdr predict ok for acks */
 347         u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
 348         u_long  tcps_pcbcachemiss;
 349         u_long  tcps_cachedrtt;         /* times cached RTT in route updated */
 350         u_long  tcps_cachedrttvar;      /* times cached rttvar updated */
 351         u_long  tcps_cachedssthresh;    /* times cached ssthresh updated */
 352         u_long  tcps_usedrtt;           /* times RTT initialized from route */
 353         u_long  tcps_usedrttvar;        /* times RTTVAR initialized from rt */
 354         u_long  tcps_usedssthresh;      /* times ssthresh initialized from rt*/
 355         u_long  tcps_persistdrop;       /* timeout in persist state */
 356         u_long  tcps_badsyn;            /* bogus SYN, e.g. premature ACK */
 357         u_long  tcps_mturesent;         /* resends due to MTU discovery */
 358         u_long  tcps_listendrop;        /* listen queue overflows */
 359
 360         u_long  tcps_sc_added;          /* entry added to syncache */
 361         u_long  tcps_sc_retransmitted;  /* syncache entry was retransmitted */
 362         u_long  tcps_sc_dupsyn;         /* duplicate SYN packet */
 363         u_long  tcps_sc_dropped;        /* could not reply to packet */
 364         u_long  tcps_sc_completed;      /* successful extraction of entry */
 365         u_long  tcps_sc_bucketoverflow; /* syncache per-bucket limit hit */
 366         u_long  tcps_sc_cacheoverflow;  /* syncache cache limit hit */
 367         u_long  tcps_sc_reset;          /* RST removed entry from syncache */
 368         u_long  tcps_sc_stale;          /* timed out or listen socket gone */
 369         u_long  tcps_sc_aborted;        /* syncache entry aborted */
 370         u_long  tcps_sc_badack;         /* removed due to bad ACK */
 371         u_long  tcps_sc_unreach;        /* ICMP unreachable received */
 372         u_long  tcps_sc_zonefail;       /* zalloc() failed */
 373         u_long  tcps_sc_sendcookie;     /* SYN cookie sent */
 374         u_long  tcps_sc_recvcookie;     /* SYN cookie received */
 375 };
 376
 377 #ifdef _KERNEL
 378
 379 #if defined(SMP)
 380 #define tcpstat tcpstats_percpu[mycpuid]
 381 #else
 382 #define tcpstat tcpstats_percpu[0]
 383 #endif
 384
 385 struct sockopt;
 386
 387 extern struct tcp_stats         tcpstats_percpu[MAXCPU];
 388
 389 static const int tcprexmtthresh = 3;
 390 #endif
 391
 392 /*
 393  * Structure to hold TCP options that are only used during segment
 394  * processing (in tcp_input), but not held in the tcpcb.
 395  * It's basically used to reduce the number of parameters
 396  * to tcp_dooptions.
 397  */
 398 struct tcpopt {
 399         u_long          to_flags;       /* which options are present */
 400 #define TOF_TS                  0x0001          /* timestamp */
 401 #define TOF_MSS                 0x0010
 402 #define TOF_SCALE               0x0020
 403 #define TOF_SACK_PERMITTED      0x0040
 404 #define TOF_SACK                0x0080
 405         u_int32_t       to_tsval;
 406         u_int32_t       to_tsecr;
 407         u_int16_t       to_mss;
 408         u_int8_t        to_requested_s_scale;
 409         u_int8_t        to_nsackblocks;
 410         struct raw_sackblock *to_sackblocks;
 411 };
 412
 413 struct syncache {
 414         inp_gen_t       sc_inp_gencnt;          /* pointer check */
 415         struct          tcpcb *sc_tp;           /* tcb for listening socket */
 416         struct          mbuf *sc_ipopts;        /* source route */
 417         struct          in_conninfo sc_inc;     /* addresses */
 418 #define sc_route        sc_inc.inc_route
 419 #define sc_route6       sc_inc.inc6_route
 420         u_int32_t       sc_tsrecent;
 421         tcp_seq         sc_irs;                 /* seq from peer */
 422         tcp_seq         sc_iss;                 /* our ISS */
 423         u_long          sc_rxttime;             /* retransmit time */
 424         u_int16_t       sc_rxtslot;             /* retransmit counter */
 425         u_int16_t       sc_peer_mss;            /* peer's MSS */
 426         u_int16_t       sc_wnd;                 /* advertised window */
 427         u_int8_t        sc_requested_s_scale:4,
 428                         sc_request_r_scale:4;
 429         u_int8_t        sc_flags;
 430 #define SCF_NOOPT               0x01            /* no TCP options */
 431 #define SCF_WINSCALE            0x02            /* negotiated window scaling */
 432 #define SCF_TIMESTAMP           0x04            /* negotiated timestamps */
 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 #define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
 445 #define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
 446
 447 /*
 448  * The smoothed round-trip time and estimated variance
 449  * are stored as fixed point numbers scaled by the values below.
 450  * For convenience, these scales are also used in smoothing the average
 451  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 452  * With these scales, srtt has 3 bits to the right of the binary point,
 453  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 454  * binary point, and is smoothed with an ALPHA of 0.75.
 455  */
 456 #define TCP_RTT_SCALE           32      /* multiplier for srtt; 3 bits frac. */
 457 #define TCP_RTT_SHIFT           5       /* shift for srtt; 3 bits frac. */
 458 #define TCP_RTTVAR_SCALE        16      /* multiplier for rttvar; 2 bits */
 459 #define TCP_RTTVAR_SHIFT        4       /* shift for rttvar; 2 bits */
 460 #define TCP_DELTA_SHIFT         2       /* see tcp_input.c */
 461
 462 /*
 463  * The initial retransmission should happen at rtt + 4 * rttvar.
 464  * Because of the way we do the smoothing, srtt and rttvar
 465  * will each average +1/2 tick of bias.  When we compute
 466  * the retransmit timer, we want 1/2 tick of rounding and
 467  * 1 extra tick because of +-1/2 tick uncertainty in the
 468  * firing of the timer.  The bias will give us exactly the
 469  * 1.5 tick we need.  But, because the bias is
 470  * statistical, we have to test that we don't drop below
 471  * the minimum feasible timer (which is 2 ticks).
 472  * This version of the macro adapted from a paper by Lawrence
 473  * Brakmo and Larry Peterson which outlines a problem caused
 474  * by insufficient precision in the original implementation,
 475  * which results in inappropriately large RTO values for very
 476  * fast networks.
 477  */
 478 #define TCP_REXMTVAL(tp) \
 479         max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
 480           + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
 481
 482 /*
 483  * TCB structure exported to user-land via sysctl(3).
 484  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
 485  * included.  Not all of our clients do.
 486  */
 487 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
 488 struct  xtcpcb {
 489         size_t  xt_len;
 490         struct  inpcb   xt_inp;
 491         struct  tcpcb   xt_tp;
 492         struct  xsocket xt_socket;
 493         u_quad_t        xt_alignment_hack;
 494 };
 495 #endif
 496
 497 /*
 498  * Names for TCP sysctl objects
 499  */
 500 #define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
 501 /* 2 was TCPCTL_DO_RFC1644 */
 502 #define TCPCTL_MSSDFLT          3       /* MSS default */
 503 #define TCPCTL_STATS            4       /* statistics (read-only) */
 504 #define TCPCTL_RTTDFLT          5       /* default RTT estimate */
 505 #define TCPCTL_KEEPIDLE         6       /* keepalive idle timer */
 506 #define TCPCTL_KEEPINTVL        7       /* interval to send keepalives */
 507 #define TCPCTL_SENDSPACE        8       /* send buffer space */
 508 #define TCPCTL_RECVSPACE        9       /* receive buffer space */
 509 #define TCPCTL_KEEPINIT         10      /* timeout for establishing syn */
 510 #define TCPCTL_PCBLIST          11      /* list of all outstanding PCBs */
 511 #define TCPCTL_DELACKTIME       12      /* time before sending delayed ACK */
 512 #define TCPCTL_V6MSSDFLT        13      /* MSS default for IPv6 */
 513 #define TCPCTL_MAXID            14
 514
 515 #define TCPCTL_NAMES { \
 516         { 0, 0 }, \
 517         { "rfc1323", CTLTYPE_INT }, \
 518           { "reserved", CTLTYPE_INT},   /* was rfc1644 */       \
 519         { "mssdflt", CTLTYPE_INT }, \
 520         { "stats", CTLTYPE_STRUCT }, \
 521         { "rttdflt", CTLTYPE_INT }, \
 522         { "keepidle", CTLTYPE_INT }, \
 523         { "keepintvl", CTLTYPE_INT }, \
 524         { "sendspace", CTLTYPE_INT }, \
 525         { "recvspace", CTLTYPE_INT }, \
 526         { "keepinit", CTLTYPE_INT }, \
 527         { "pcblist", CTLTYPE_STRUCT }, \
 528         { "delacktime", CTLTYPE_INT }, \
 529         { "v6mssdflt", CTLTYPE_INT }, \
 530 }
 531
 532 #ifdef _KERNEL
 533 #ifdef SYSCTL_DECL
 534 SYSCTL_DECL(_net_inet_tcp);
 535 #endif
 536
 537 #define TCP_DO_SACK(tp)         ((tp)->t_flags & TF_SACK_PERMITTED)
 538
 539 TAILQ_HEAD(tcpcbackqhead,tcpcb);
 540
 541 extern  struct inpcbinfo tcbinfo[];
 542 extern  struct tcpcbackqhead tcpcbackq[];
 543
 544 extern  int tcp_mssdflt;        /* XXX */
 545 extern  int tcp_minmss;
 546 extern  int tcp_delack_enabled;
 547 extern  int path_mtu_discovery;
 548
 549 int      tcp_addrcpu(in_addr_t faddr, in_port_t fport,
 550             in_addr_t laddr, in_port_t lport);
 551 struct lwkt_port *
 552         tcp_addrport(in_addr_t faddr, in_port_t fport,
 553             in_addr_t laddr, in_port_t lport);
 554 struct lwkt_port *tcp_addrport0(void);
 555 void     tcp_canceltimers (struct tcpcb *);
 556 struct tcpcb *
 557          tcp_close (struct tcpcb *);
 558 void     tcpmsg_service_loop (void *);
 559 void     tcp_ctlinput (int, struct sockaddr *, void *);
 560 int      tcp_ctloutput (struct socket *, struct sockopt *);
 561 struct lwkt_port *
 562          tcp_cport(int cpu);
 563 struct tcpcb *
 564          tcp_drop (struct tcpcb *, int);
 565 void     tcp_drain (void);
 566 void     tcp_fasttimo (void);
 567 void     tcp_init (void);
 568 void     tcp_thread_init (void);
 569 void     tcp_input (struct mbuf *, ...);
 570 void     tcp_mss (struct tcpcb *, int);
 571 int      tcp_mssopt (struct tcpcb *);
 572 void     tcp_drop_syn_sent (struct inpcb *, int);
 573 void     tcp_mtudisc (struct inpcb *, int);
 574 struct tcpcb *
 575          tcp_newtcpcb (struct inpcb *);
 576 int      tcp_output (struct tcpcb *);
 577 void     tcp_quench (struct inpcb *, int);
 578 void     tcp_respond (struct tcpcb *, void *,
 579             struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
 580 struct rtentry *
 581          tcp_rtlookup (struct in_conninfo *);
 582 int      tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq);
 583 void     tcp_sack_cleanup(struct scoreboard *scb);
 584 int      tcp_sack_ndsack_blocks(struct raw_sackblock *blocks,
 585             const int numblocks, tcp_seq snd_una);
 586 void     tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen);
 587 boolean_t
 588          tcp_sack_has_sacked(struct scoreboard *scb, u_int amount);
 589 void     tcp_sack_tcpcb_init(struct tcpcb *tp);
 590 uint32_t tcp_sack_compute_pipe(struct tcpcb *tp);
 591 boolean_t
 592          tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *len,
 593                           boolean_t *losdup);
 594 #ifdef later
 595 void     tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una,
 596                                     u_int maxseg);
 597 void     tcp_sack_save_scoreboard(struct scoreboard *scb);
 598 #endif
 599 void     tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt);
 600 void     tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to);
 601 void     tcp_save_congestion_state(struct tcpcb *tp);
 602 void     tcp_revert_congestion_state(struct tcpcb *tp);
 603 void     tcp_setpersist (struct tcpcb *);
 604 void     tcp_slowtimo (void);
 605 struct tcptemp *tcp_maketemplate (struct tcpcb *);
 606 void     tcp_freetemplate (struct tcptemp *);
 607 void     tcp_fillheaders (struct tcpcb *, void *, void *);
 608 struct lwkt_port *
 609          tcp_soport(struct socket *, struct sockaddr *, struct mbuf **);
 610 struct lwkt_port *
 611          tcp_soport_attach(struct socket *);
 612 struct lwkt_port *
 613          tcp_ctlport(int, struct sockaddr *, void *);
 614 struct tcpcb *
 615          tcp_timers (struct tcpcb *, int);
 616 void     tcp_trace (short, short, struct tcpcb *, void *, struct tcphdr *,
 617                         int);
 618 void     tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
 619 void     syncache_init(void);
 620 void     syncache_unreach(struct in_conninfo *, struct tcphdr *);
 621 int      syncache_expand(struct in_conninfo *, struct tcphdr *,
 622              struct socket **, struct mbuf *);
 623 int      syncache_add(struct in_conninfo *, struct tcpopt *,
 624              struct tcphdr *, struct socket **, struct mbuf *);
 625 void     syncache_chkrst(struct in_conninfo *, struct tcphdr *);
 626 void     syncache_badack(struct in_conninfo *);
 627 void     syncache_destroy(struct tcpcb *tp);
 628
 629
 630 extern  struct pr_usrreqs tcp_usrreqs;
 631 extern  u_long tcp_sendspace;
 632 extern  u_long tcp_recvspace;
 633 tcp_seq tcp_new_isn (struct tcpcb *);
 634
 635 #endif /* _KERNEL */
 636
 637 #endif /* _NETINET_TCP_VAR_H_ */