workbench/network/stacks/AROSTCP/bsdsocket/netinet/tcp_var.h

   1 /*
   2  * Copyright (c) 1982, 1986 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)tcp_var.h   7.10 (Berkeley) 6/28/90
  34  */
  35
  36 #ifndef TCP_VAR_H
  37 #define TCP_VAR_H
  38
  39 /*
  40  * Kernel variables for tcp.
  41  */
  42
  43 /*
  44  * Tcp control block, one per tcp; fields:
  45  */
  46 struct tcpcb {
  47         struct  tcpiphdr *seg_next;     /* sequencing queue */
  48         struct  tcpiphdr *seg_prev;
  49         short   t_state;                /* state of this connection */
  50         short   t_timer[TCPT_NTIMERS];  /* tcp timers */
  51         short   t_rxtshift;             /* log(2) of rexmt exp. backoff */
  52         short   t_rxtcur;               /* current retransmit value */
  53         short   t_dupacks;              /* consecutive dup acks recd */
  54         u_short t_maxseg;               /* maximum segment size */
  55         char    t_force;                /* 1 if forcing out a byte */
  56         u_char  t_flags;
  57 #define TF_ACKNOW       0x01            /* ack peer immediately */
  58 #define TF_DELACK       0x02            /* ack, but try to delay it */
  59 #define TF_NODELAY      0x04            /* don't delay packets to coalesce */
  60 #define TF_NOOPT        0x08            /* don't use tcp options */
  61 #define TF_SENTFIN      0x10            /* have sent FIN */
  62         struct  tcpiphdr *t_template;   /* skeletal packet for transmit */
  63         struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
  64 /*
  65  * The following fields are used as in the protocol specification.
  66  * See RFC783, Dec. 1981, page 21.
  67  */
  68 /* send sequence variables */
  69         tcp_seq snd_una;                /* send unacknowledged */
  70         tcp_seq snd_nxt;                /* send next */
  71         tcp_seq snd_up;                 /* send urgent pointer */
  72         tcp_seq snd_wl1;                /* window update seg seq number */
  73         tcp_seq snd_wl2;                /* window update seg ack number */
  74         tcp_seq iss;                    /* initial send sequence number */
  75         u_short snd_wnd;                /* send window */
  76 /* receive sequence variables */
  77         u_short rcv_wnd;                /* receive window */
  78         tcp_seq rcv_nxt;                /* receive next */
  79         tcp_seq rcv_up;                 /* receive urgent pointer */
  80         tcp_seq irs;                    /* initial receive sequence number */
  81 /*
  82  * Additional variables for this implementation.
  83  */
  84 /* receive variables */
  85         tcp_seq rcv_adv;                /* advertised window */
  86 /* retransmit variables */
  87         tcp_seq snd_max;                /* highest sequence number sent;
  88                                          * used to recognize retransmits
  89                                          */
  90 /* congestion control (for slow start, source quench, retransmit after loss) */
  91         u_short snd_cwnd;               /* congestion-controlled window */
  92         u_short snd_ssthresh;           /* snd_cwnd size threshhold for
  93                                          * for slow start exponential to
  94                                          * linear switch
  95                                          */
  96 /*
  97  * transmit timing stuff.  See below for scale of srtt and rttvar.
  98  * "Variance" is actually smoothed difference.
  99  */
 100         short   t_idle;                 /* inactivity time */
 101         short   t_rtt;                  /* round trip time */
 102         tcp_seq t_rtseq;                /* sequence number being timed */
 103         short   t_srtt;                 /* smoothed round-trip time */
 104         short   t_rttvar;               /* variance in round-trip time */
 105         u_short t_rttmin;               /* minimum rtt allowed */
 106         u_short max_sndwnd;             /* largest window peer has offered */
 107
 108 /* out-of-band data */
 109         char    t_oobflags;             /* have some */
 110         char    t_iobc;                 /* input character */
 111 #define TCPOOB_HAVEDATA 0x01
 112 #define TCPOOB_HADDATA  0x02
 113         short   t_softerror;            /* possible error not yet reported */
 114 };
 115
 116 #define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
 117 #define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
 118
 119 /*
 120  * The smoothed round-trip time and estimated variance
 121  * are stored as fixed point numbers scaled by the values below.
 122  * For convenience, these scales are also used in smoothing the average
 123  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 124  * With these scales, srtt has 3 bits to the right of the binary point,
 125  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 126  * binary point, and is smoothed with an ALPHA of 0.75.
 127  */
 128 #define TCP_RTT_SCALE           8       /* multiplier for srtt; 3 bits frac. */
 129 #define TCP_RTT_SHIFT           3       /* shift for srtt; 3 bits frac. */
 130 #define TCP_RTTVAR_SCALE        4       /* multiplier for rttvar; 2 bits */
 131 #define TCP_RTTVAR_SHIFT        2       /* multiplier for rttvar; 2 bits */
 132
 133 /*
 134  * The initial retransmission should happen at rtt + 4 * rttvar.
 135  * Because of the way we do the smoothing, srtt and rttvar
 136  * will each average +1/2 tick of bias.  When we compute
 137  * the retransmit timer, we want 1/2 tick of rounding and
 138  * 1 extra tick because of +-1/2 tick uncertainty in the
 139  * firing of the timer.  The bias will give us exactly the
 140  * 1.5 tick we need.  But, because the bias is
 141  * statistical, we have to test that we don't drop below
 142  * the minimum feasible timer (which is 2 ticks).
 143  * This macro assumes that the value of TCP_RTTVAR_SCALE
 144  * is the same as the multiplier for rttvar.
 145  */
 146 #define TCP_REXMTVAL(tp) \
 147         (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
 148
 149 /* XXX
 150  * We want to avoid doing m_pullup on incoming packets but that
 151  * means avoiding dtom on the tcp reassembly code.  That in turn means
 152  * keeping an mbuf pointer in the reassembly queue (since we might
 153  * have a cluster).  As a quick hack, the source & destination
 154  * port numbers (which are no longer needed once we've located the
 155  * tcpcb) are overlayed with an mbuf pointer.
 156  */
 157 #define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))
 158
 159 /*
 160  * TCP statistics.
 161  * Many of these should be kept per connection,
 162  * but that's inconvenient at the moment.
 163  */
 164 struct  tcpstat {
 165         u_long  tcps_connattempt;       /* connections initiated */
 166         u_long  tcps_accepts;           /* connections accepted */
 167         u_long  tcps_connects;          /* connections established */
 168         u_long  tcps_drops;             /* connections dropped */
 169         u_long  tcps_conndrops;         /* embryonic connections dropped */
 170         u_long  tcps_closed;            /* conn. closed (includes drops) */
 171         u_long  tcps_segstimed;         /* segs where we tried to get rtt */
 172         u_long  tcps_rttupdated;        /* times we succeeded */
 173         u_long  tcps_delack;            /* delayed acks sent */
 174         u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
 175         u_long  tcps_rexmttimeo;        /* retransmit timeouts */
 176         u_long  tcps_persisttimeo;      /* persist timeouts */
 177         u_long  tcps_keeptimeo;         /* keepalive timeouts */
 178         u_long  tcps_keepprobe;         /* keepalive probes sent */
 179         u_long  tcps_keepdrops;         /* connections dropped in keepalive */
 180
 181         u_long  tcps_sndtotal;          /* total packets sent */
 182         u_long  tcps_sndpack;           /* data packets sent */
 183         u_long  tcps_sndbyte;           /* data bytes sent */
 184         u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
 185         u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
 186         u_long  tcps_sndacks;           /* ack-only packets sent */
 187         u_long  tcps_sndprobe;          /* window probes sent */
 188         u_long  tcps_sndurg;            /* packets sent with URG only */
 189         u_long  tcps_sndwinup;          /* window update-only packets sent */
 190         u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
 191
 192         u_long  tcps_rcvtotal;          /* total packets received */
 193         u_long  tcps_rcvpack;           /* packets received in sequence */
 194         u_long  tcps_rcvbyte;           /* bytes received in sequence */
 195         u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
 196         u_long  tcps_rcvbadoff;         /* packets received with bad offset */
 197         u_long  tcps_rcvshort;          /* packets received too short */
 198         u_long  tcps_rcvduppack;        /* duplicate-only packets received */
 199         u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
 200         u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
 201         u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
 202         u_long  tcps_rcvoopack;         /* out-of-order packets received */
 203         u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
 204         u_long  tcps_rcvpackafterwin;   /* packets with data after window */
 205         u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
 206         u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
 207         u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
 208         u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
 209         u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
 210         u_long  tcps_rcvackpack;        /* rcvd ack packets */
 211         u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
 212         u_long  tcps_rcvwinupd;         /* rcvd window update packets */
 213 };
 214
 215 #ifdef KERNEL
 216 extern struct   inpcb tcb;              /* head of queue of active tcpcb's */
 217 extern struct   tcpstat tcpstat;        /* tcp statistics */
 218 #endif
 219
 220 #endif /* !TCP_VAR_H */