slirp/tcp_var.h

   1 /*
   2  * Copyright (c) 1982, 1986, 1993, 1994
   3  *      The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)tcp_var.h   8.3 (Berkeley) 4/10/94
  30  * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
  31  */
  32
  33 #ifndef _TCP_VAR_H_
  34 #define _TCP_VAR_H_
  35
  36 #include "tcpip.h"
  37 #include "tcp_timer.h"
  38
  39 /*
  40  * Tcp control block, one per tcp; fields:
  41  */
  42 struct tcpcb {
  43         struct tcpiphdr *seg_next;      /* sequencing queue */
  44         struct tcpiphdr *seg_prev;
  45         short   t_state;                /* state of this connection */
  46         short   t_timer[TCPT_NTIMERS];  /* tcp timers */
  47         short   t_rxtshift;             /* log(2) of rexmt exp. backoff */
  48         short   t_rxtcur;               /* current retransmit value */
  49         short   t_dupacks;              /* consecutive dup acks recd */
  50         u_short t_maxseg;               /* maximum segment size */
  51         char    t_force;                /* 1 if forcing out a byte */
  52         u_short t_flags;
  53 #define TF_ACKNOW       0x0001          /* ack peer immediately */
  54 #define TF_DELACK       0x0002          /* ack, but try to delay it */
  55 #define TF_NODELAY      0x0004          /* don't delay packets to coalesce */
  56 #define TF_NOOPT        0x0008          /* don't use tcp options */
  57 #define TF_SENTFIN      0x0010          /* have sent FIN */
  58 #define TF_REQ_SCALE    0x0020          /* have/will request window scaling */
  59 #define TF_RCVD_SCALE   0x0040          /* other side has requested scaling */
  60 #define TF_REQ_TSTMP    0x0080          /* have/will request timestamps */
  61 #define TF_RCVD_TSTMP   0x0100          /* a timestamp was received in SYN */
  62 #define TF_SACK_PERMIT  0x0200          /* other side said I could SACK */
  63
  64         /* Make it static  for now */
  65 /*      struct  tcpiphdr *t_template;   / * skeletal packet for transmit */
  66         struct  tcpiphdr t_template;
  67
  68         struct  socket *t_socket;               /* back pointer to socket */
  69 /*
  70  * The following fields are used as in the protocol specification.
  71  * See RFC783, Dec. 1981, page 21.
  72  */
  73 /* send sequence variables */
  74         tcp_seq snd_una;                /* send unacknowledged */
  75         tcp_seq snd_nxt;                /* send next */
  76         tcp_seq snd_up;                 /* send urgent pointer */
  77         tcp_seq snd_wl1;                /* window update seg seq number */
  78         tcp_seq snd_wl2;                /* window update seg ack number */
  79         tcp_seq iss;                    /* initial send sequence number */
  80         u_int32_t snd_wnd;              /* send window */
  81 /* receive sequence variables */
  82         u_int32_t rcv_wnd;              /* receive window */
  83         tcp_seq rcv_nxt;                /* receive next */
  84         tcp_seq rcv_up;                 /* receive urgent pointer */
  85         tcp_seq irs;                    /* initial receive sequence number */
  86 /*
  87  * Additional variables for this implementation.
  88  */
  89 /* receive variables */
  90         tcp_seq rcv_adv;                /* advertised window */
  91 /* retransmit variables */
  92         tcp_seq snd_max;                /* highest sequence number sent;
  93                                          * used to recognize retransmits
  94                                          */
  95 /* congestion control (for slow start, source quench, retransmit after loss) */
  96         u_int32_t snd_cwnd;             /* congestion-controlled window */
  97         u_int32_t snd_ssthresh;         /* snd_cwnd size threshold for
  98                                          * for slow start exponential to
  99                                          * linear switch
 100                                          */
 101 /*
 102  * transmit timing stuff.  See below for scale of srtt and rttvar.
 103  * "Variance" is actually smoothed difference.
 104  */
 105         short   t_idle;                 /* inactivity time */
 106         short   t_rtt;                  /* round trip time */
 107         tcp_seq t_rtseq;                /* sequence number being timed */
 108         short   t_srtt;                 /* smoothed round-trip time */
 109         short   t_rttvar;               /* variance in round-trip time */
 110         u_short t_rttmin;               /* minimum rtt allowed */
 111         u_int32_t max_sndwnd;           /* largest window peer has offered */
 112
 113 /* out-of-band data */
 114         char    t_oobflags;             /* have some */
 115         char    t_iobc;                 /* input character */
 116 #define TCPOOB_HAVEDATA 0x01
 117 #define TCPOOB_HADDATA  0x02
 118         short   t_softerror;            /* possible error not yet reported */
 119
 120 /* RFC 1323 variables */
 121         u_char  snd_scale;              /* window scaling for send window */
 122         u_char  rcv_scale;              /* window scaling for recv window */
 123         u_char  request_r_scale;        /* pending window scaling */
 124         u_char  requested_s_scale;
 125         u_int32_t       ts_recent;              /* timestamp echo data */
 126         u_int32_t       ts_recent_age;          /* when last updated */
 127         tcp_seq last_ack_sent;
 128
 129 };
 130
 131 #define sototcpcb(so)   ((so)->so_tcpcb)
 132
 133 /*
 134  * The smoothed round-trip time and estimated variance
 135  * are stored as fixed point numbers scaled by the values below.
 136  * For convenience, these scales are also used in smoothing the average
 137  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 138  * With these scales, srtt has 3 bits to the right of the binary point,
 139  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 140  * binary point, and is smoothed with an ALPHA of 0.75.
 141  */
 142 #define TCP_RTT_SCALE           8       /* multiplier for srtt; 3 bits frac. */
 143 #define TCP_RTT_SHIFT           3       /* shift for srtt; 3 bits frac. */
 144 #define TCP_RTTVAR_SCALE        4       /* multiplier for rttvar; 2 bits */
 145 #define TCP_RTTVAR_SHIFT        2       /* multiplier for rttvar; 2 bits */
 146
 147 /*
 148  * The initial retransmission should happen at rtt + 4 * rttvar.
 149  * Because of the way we do the smoothing, srtt and rttvar
 150  * will each average +1/2 tick of bias.  When we compute
 151  * the retransmit timer, we want 1/2 tick of rounding and
 152  * 1 extra tick because of +-1/2 tick uncertainty in the
 153  * firing of the timer.  The bias will give us exactly the
 154  * 1.5 tick we need.  But, because the bias is
 155  * statistical, we have to test that we don't drop below
 156  * the minimum feasible timer (which is 2 ticks).
 157  * This macro assumes that the value of TCP_RTTVAR_SCALE
 158  * is the same as the multiplier for rttvar.
 159  */
 160 #define TCP_REXMTVAL(tp) \
 161         (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
 162
 163 #ifdef LOG_ENABLED
 164 /*
 165  * TCP statistics.
 166  * Many of these should be kept per connection,
 167  * but that's inconvenient at the moment.
 168  */
 169 struct tcpstat {
 170         u_long  tcps_connattempt;       /* connections initiated */
 171         u_long  tcps_accepts;           /* connections accepted */
 172         u_long  tcps_connects;          /* connections established */
 173         u_long  tcps_drops;             /* connections dropped */
 174         u_long  tcps_conndrops;         /* embryonic connections dropped */
 175         u_long  tcps_closed;            /* conn. closed (includes drops) */
 176         u_long  tcps_segstimed;         /* segs where we tried to get rtt */
 177         u_long  tcps_rttupdated;        /* times we succeeded */
 178         u_long  tcps_delack;            /* delayed acks sent */
 179         u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
 180         u_long  tcps_rexmttimeo;        /* retransmit timeouts */
 181         u_long  tcps_persisttimeo;      /* persist timeouts */
 182         u_long  tcps_keeptimeo;         /* keepalive timeouts */
 183         u_long  tcps_keepprobe;         /* keepalive probes sent */
 184         u_long  tcps_keepdrops;         /* connections dropped in keepalive */
 185
 186         u_long  tcps_sndtotal;          /* total packets sent */
 187         u_long  tcps_sndpack;           /* data packets sent */
 188         u_long  tcps_sndbyte;           /* data bytes sent */
 189         u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
 190         u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
 191         u_long  tcps_sndacks;           /* ack-only packets sent */
 192         u_long  tcps_sndprobe;          /* window probes sent */
 193         u_long  tcps_sndurg;            /* packets sent with URG only */
 194         u_long  tcps_sndwinup;          /* window update-only packets sent */
 195         u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
 196
 197         u_long  tcps_rcvtotal;          /* total packets received */
 198         u_long  tcps_rcvpack;           /* packets received in sequence */
 199         u_long  tcps_rcvbyte;           /* bytes received in sequence */
 200         u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
 201         u_long  tcps_rcvbadoff;         /* packets received with bad offset */
 202 /*      u_long  tcps_rcvshort;  */      /* packets received too short */
 203         u_long  tcps_rcvduppack;        /* duplicate-only packets received */
 204         u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
 205         u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
 206         u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
 207         u_long  tcps_rcvoopack;         /* out-of-order packets received */
 208         u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
 209         u_long  tcps_rcvpackafterwin;   /* packets with data after window */
 210         u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
 211         u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
 212         u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
 213         u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
 214         u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
 215         u_long  tcps_rcvackpack;        /* rcvd ack packets */
 216         u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
 217         u_long  tcps_rcvwinupd;         /* rcvd window update packets */
 218 /*      u_long  tcps_pawsdrop;  */      /* segments dropped due to PAWS */
 219         u_long  tcps_predack;           /* times hdr predict ok for acks */
 220         u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
 221         u_long  tcps_socachemiss;       /* tcp_last_so misses */
 222         u_long  tcps_didnuttin;         /* Times tcp_output didn't do anything XXX */
 223 };
 224
 225 extern struct   tcpstat tcpstat;        /* tcp statistics */
 226 #endif
 227
 228 extern u_int32_t        tcp_now;                /* for RFC 1323 timestamps */
 229
 230 #endif