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. 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   8.3 (Berkeley) 4/10/94
  34  * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
  35  */
  36
  37 #ifndef _TCP_VAR_H_
  38 #define _TCP_VAR_H_
  39
  40 #include "tcpip.h"
  41 #include "tcp_timer.h"
  42
  43 #if SIZEOF_CHAR_P == 4
  44  typedef struct tcpiphdr *tcpiphdrp_32;
  45 #else
  46  typedef u_int32_t tcpiphdrp_32;
  47 #endif
  48
  49 /*
  50  * Tcp control block, one per tcp; fields:
  51  */
  52 struct tcpcb {
  53         tcpiphdrp_32 seg_next;  /* sequencing queue */
  54         tcpiphdrp_32 seg_prev;
  55         short   t_state;                /* state of this connection */
  56         short   t_timer[TCPT_NTIMERS];  /* tcp timers */
  57         short   t_rxtshift;             /* log(2) of rexmt exp. backoff */
  58         short   t_rxtcur;               /* current retransmit value */
  59         short   t_dupacks;              /* consecutive dup acks recd */
  60         u_short t_maxseg;               /* maximum segment size */
  61         char    t_force;                /* 1 if forcing out a byte */
  62         u_short t_flags;
  63 #define TF_ACKNOW       0x0001          /* ack peer immediately */
  64 #define TF_DELACK       0x0002          /* ack, but try to delay it */
  65 #define TF_NODELAY      0x0004          /* don't delay packets to coalesce */
  66 #define TF_NOOPT        0x0008          /* don't use tcp options */
  67 #define TF_SENTFIN      0x0010          /* have sent FIN */
  68 #define TF_REQ_SCALE    0x0020          /* have/will request window scaling */
  69 #define TF_RCVD_SCALE   0x0040          /* other side has requested scaling */
  70 #define TF_REQ_TSTMP    0x0080          /* have/will request timestamps */
  71 #define TF_RCVD_TSTMP   0x0100          /* a timestamp was received in SYN */
  72 #define TF_SACK_PERMIT  0x0200          /* other side said I could SACK */
  73
  74         /* Make it static  for now */
  75 /*      struct  tcpiphdr *t_template;   / * skeletal packet for transmit */
  76         struct  tcpiphdr t_template;
  77
  78         struct  socket *t_socket;               /* back pointer to socket */
  79 /*
  80  * The following fields are used as in the protocol specification.
  81  * See RFC783, Dec. 1981, page 21.
  82  */
  83 /* send sequence variables */
  84         tcp_seq snd_una;                /* send unacknowledged */
  85         tcp_seq snd_nxt;                /* send next */
  86         tcp_seq snd_up;                 /* send urgent pointer */
  87         tcp_seq snd_wl1;                /* window update seg seq number */
  88         tcp_seq snd_wl2;                /* window update seg ack number */
  89         tcp_seq iss;                    /* initial send sequence number */
  90         u_int32_t snd_wnd;              /* send window */
  91 /* receive sequence variables */
  92         u_int32_t rcv_wnd;              /* receive window */
  93         tcp_seq rcv_nxt;                /* receive next */
  94         tcp_seq rcv_up;                 /* receive urgent pointer */
  95         tcp_seq irs;                    /* initial receive sequence number */
  96 /*
  97  * Additional variables for this implementation.
  98  */
  99 /* receive variables */
 100         tcp_seq rcv_adv;                /* advertised window */
 101 /* retransmit variables */
 102         tcp_seq snd_max;                /* highest sequence number sent;
 103                                          * used to recognize retransmits
 104                                          */
 105 /* congestion control (for slow start, source quench, retransmit after loss) */
 106         u_int32_t snd_cwnd;             /* congestion-controlled window */
 107         u_int32_t snd_ssthresh;         /* snd_cwnd size threshold for
 108                                          * for slow start exponential to
 109                                          * linear switch
 110                                          */
 111 /*
 112  * transmit timing stuff.  See below for scale of srtt and rttvar.
 113  * "Variance" is actually smoothed difference.
 114  */
 115         short   t_idle;                 /* inactivity time */
 116         short   t_rtt;                  /* round trip time */
 117         tcp_seq t_rtseq;                /* sequence number being timed */
 118         short   t_srtt;                 /* smoothed round-trip time */
 119         short   t_rttvar;               /* variance in round-trip time */
 120         u_short t_rttmin;               /* minimum rtt allowed */
 121         u_int32_t max_sndwnd;           /* largest window peer has offered */
 122
 123 /* out-of-band data */
 124         char    t_oobflags;             /* have some */
 125         char    t_iobc;                 /* input character */
 126 #define TCPOOB_HAVEDATA 0x01
 127 #define TCPOOB_HADDATA  0x02
 128         short   t_softerror;            /* possible error not yet reported */
 129
 130 /* RFC 1323 variables */
 131         u_char  snd_scale;              /* window scaling for send window */
 132         u_char  rcv_scale;              /* window scaling for recv window */
 133         u_char  request_r_scale;        /* pending window scaling */
 134         u_char  requested_s_scale;
 135         u_int32_t       ts_recent;              /* timestamp echo data */
 136         u_int32_t       ts_recent_age;          /* when last updated */
 137         tcp_seq last_ack_sent;
 138
 139 };
 140
 141 #define sototcpcb(so)   ((so)->so_tcpcb)
 142
 143 /*
 144  * The smoothed round-trip time and estimated variance
 145  * are stored as fixed point numbers scaled by the values below.
 146  * For convenience, these scales are also used in smoothing the average
 147  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
 148  * With these scales, srtt has 3 bits to the right of the binary point,
 149  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
 150  * binary point, and is smoothed with an ALPHA of 0.75.
 151  */
 152 #define TCP_RTT_SCALE           8       /* multiplier for srtt; 3 bits frac. */
 153 #define TCP_RTT_SHIFT           3       /* shift for srtt; 3 bits frac. */
 154 #define TCP_RTTVAR_SCALE        4       /* multiplier for rttvar; 2 bits */
 155 #define TCP_RTTVAR_SHIFT        2       /* multiplier for rttvar; 2 bits */
 156
 157 /*
 158  * The initial retransmission should happen at rtt + 4 * rttvar.
 159  * Because of the way we do the smoothing, srtt and rttvar
 160  * will each average +1/2 tick of bias.  When we compute
 161  * the retransmit timer, we want 1/2 tick of rounding and
 162  * 1 extra tick because of +-1/2 tick uncertainty in the
 163  * firing of the timer.  The bias will give us exactly the
 164  * 1.5 tick we need.  But, because the bias is
 165  * statistical, we have to test that we don't drop below
 166  * the minimum feasible timer (which is 2 ticks).
 167  * This macro assumes that the value of TCP_RTTVAR_SCALE
 168  * is the same as the multiplier for rttvar.
 169  */
 170 #define TCP_REXMTVAL(tp) \
 171         (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
 172
 173 /* XXX
 174  * We want to avoid doing m_pullup on incoming packets but that
 175  * means avoiding dtom on the tcp reassembly code.  That in turn means
 176  * keeping an mbuf pointer in the reassembly queue (since we might
 177  * have a cluster).  As a quick hack, the source & destination
 178  * port numbers (which are no longer needed once we've located the
 179  * tcpcb) are overlayed with an mbuf pointer.
 180  */
 181 #if SIZEOF_CHAR_P == 4
 182 typedef struct mbuf *mbufp_32;
 183 #else
 184 typedef u_int32_t mbufp_32;
 185 #endif
 186 #define REASS_MBUF(ti) (*(mbufp_32 *)&((ti)->ti_t))
 187
 188 #ifdef LOG_ENABLED
 189 /*
 190  * TCP statistics.
 191  * Many of these should be kept per connection,
 192  * but that's inconvenient at the moment.
 193  */
 194 struct tcpstat {
 195         u_long  tcps_connattempt;       /* connections initiated */
 196         u_long  tcps_accepts;           /* connections accepted */
 197         u_long  tcps_connects;          /* connections established */
 198         u_long  tcps_drops;             /* connections dropped */
 199         u_long  tcps_conndrops;         /* embryonic connections dropped */
 200         u_long  tcps_closed;            /* conn. closed (includes drops) */
 201         u_long  tcps_segstimed;         /* segs where we tried to get rtt */
 202         u_long  tcps_rttupdated;        /* times we succeeded */
 203         u_long  tcps_delack;            /* delayed acks sent */
 204         u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
 205         u_long  tcps_rexmttimeo;        /* retransmit timeouts */
 206         u_long  tcps_persisttimeo;      /* persist timeouts */
 207         u_long  tcps_keeptimeo;         /* keepalive timeouts */
 208         u_long  tcps_keepprobe;         /* keepalive probes sent */
 209         u_long  tcps_keepdrops;         /* connections dropped in keepalive */
 210
 211         u_long  tcps_sndtotal;          /* total packets sent */
 212         u_long  tcps_sndpack;           /* data packets sent */
 213         u_long  tcps_sndbyte;           /* data bytes sent */
 214         u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
 215         u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
 216         u_long  tcps_sndacks;           /* ack-only packets sent */
 217         u_long  tcps_sndprobe;          /* window probes sent */
 218         u_long  tcps_sndurg;            /* packets sent with URG only */
 219         u_long  tcps_sndwinup;          /* window update-only packets sent */
 220         u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
 221
 222         u_long  tcps_rcvtotal;          /* total packets received */
 223         u_long  tcps_rcvpack;           /* packets received in sequence */
 224         u_long  tcps_rcvbyte;           /* bytes received in sequence */
 225         u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
 226         u_long  tcps_rcvbadoff;         /* packets received with bad offset */
 227 /*      u_long  tcps_rcvshort;  */      /* packets received too short */
 228         u_long  tcps_rcvduppack;        /* duplicate-only packets received */
 229         u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
 230         u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
 231         u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
 232         u_long  tcps_rcvoopack;         /* out-of-order packets received */
 233         u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
 234         u_long  tcps_rcvpackafterwin;   /* packets with data after window */
 235         u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
 236         u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
 237         u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
 238         u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
 239         u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
 240         u_long  tcps_rcvackpack;        /* rcvd ack packets */
 241         u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
 242         u_long  tcps_rcvwinupd;         /* rcvd window update packets */
 243 /*      u_long  tcps_pawsdrop;  */      /* segments dropped due to PAWS */
 244         u_long  tcps_predack;           /* times hdr predict ok for acks */
 245         u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
 246         u_long  tcps_socachemiss;       /* tcp_last_so misses */
 247         u_long  tcps_didnuttin;         /* Times tcp_output didn't do anything XXX */
 248 };
 249
 250 extern struct   tcpstat tcpstat;        /* tcp statistics */
 251 #endif
 252
 253 extern u_int32_t        tcp_now;                /* for RFC 1323 timestamps */
 254
 255 #endif