slirp/tcp.h

   1 /*
   2  * Copyright (c) 1982, 1986, 1993
   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.h       8.1 (Berkeley) 6/10/93
  34  * tcp.h,v 1.3 1994/08/21 05:27:34 paul Exp
  35  */
  36
  37 #ifndef _TCP_H_
  38 #define _TCP_H_
  39
  40 typedef u_int32_t       tcp_seq;
  41
  42 #define      PR_SLOWHZ       2               /* 2 slow timeouts per second (approx) */
  43 #define      PR_FASTHZ       5               /* 5 fast timeouts per second (not important) */
  44
  45 extern int tcp_rcvspace;
  46 extern int tcp_sndspace;
  47 extern struct socket *tcp_last_so;
  48
  49 #define TCP_SNDSPACE 8192
  50 #define TCP_RCVSPACE 8192
  51
  52 /*
  53  * TCP header.
  54  * Per RFC 793, September, 1981.
  55  */
  56 struct tcphdr {
  57         u_int16_t       th_sport;               /* source port */
  58         u_int16_t       th_dport;               /* destination port */
  59         tcp_seq th_seq;                 /* sequence number */
  60         tcp_seq th_ack;                 /* acknowledgement number */
  61 #ifdef WORDS_BIGENDIAN
  62         u_int   th_off:4,               /* data offset */
  63                 th_x2:4;                /* (unused) */
  64 #else
  65         u_int   th_x2:4,                /* (unused) */
  66                 th_off:4;               /* data offset */
  67 #endif
  68         u_int8_t        th_flags;
  69 #define TH_FIN  0x01
  70 #define TH_SYN  0x02
  71 #define TH_RST  0x04
  72 #define TH_PUSH 0x08
  73 #define TH_ACK  0x10
  74 #define TH_URG  0x20
  75         u_int16_t       th_win;                 /* window */
  76         u_int16_t       th_sum;                 /* checksum */
  77         u_int16_t       th_urp;                 /* urgent pointer */
  78 };
  79
  80 #include "tcp_var.h"
  81
  82 #define TCPOPT_EOL              0
  83 #define TCPOPT_NOP              1
  84 #define TCPOPT_MAXSEG           2
  85 #define    TCPOLEN_MAXSEG               4
  86 #define TCPOPT_WINDOW           3
  87 #define    TCPOLEN_WINDOW               3
  88 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
  89 #define    TCPOLEN_SACK_PERMITTED       2
  90 #define TCPOPT_SACK             5               /* Experimental */
  91 #define TCPOPT_TIMESTAMP        8
  92 #define    TCPOLEN_TIMESTAMP            10
  93 #define    TCPOLEN_TSTAMP_APPA          (TCPOLEN_TIMESTAMP+2) /* appendix A */
  94
  95 #define TCPOPT_TSTAMP_HDR       \
  96     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
  97
  98 /*
  99  * Default maximum segment size for TCP.
 100  * With an IP MSS of 576, this is 536,
 101  * but 512 is probably more convenient.
 102  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 103  */
 104 #define TCP_MSS 512
 105
 106 #define TCP_MAXWIN      65535   /* largest value for (unscaled) window */
 107
 108 #define TCP_MAX_WINSHIFT        14      /* maximum window shift */
 109
 110 /*
 111  * User-settable options (used with setsockopt).
 112  */
 113 /* #define      TCP_NODELAY     0x01 */ /* don't delay send to coalesce packets */
 114 /* #define      TCP_MAXSEG      0x02 */ /* set maximum segment size */
 115
 116 /*
 117  * TCP FSM state definitions.
 118  * Per RFC793, September, 1981.
 119  */
 120
 121 #define TCP_NSTATES     11
 122
 123 #define TCPS_CLOSED             0       /* closed */
 124 #define TCPS_LISTEN             1       /* listening for connection */
 125 #define TCPS_SYN_SENT           2       /* active, have sent syn */
 126 #define TCPS_SYN_RECEIVED       3       /* have send and received syn */
 127 /* states < TCPS_ESTABLISHED are those where connections not established */
 128 #define TCPS_ESTABLISHED        4       /* established */
 129 #define TCPS_CLOSE_WAIT         5       /* rcvd fin, waiting for close */
 130 /* states > TCPS_CLOSE_WAIT are those where user has closed */
 131 #define TCPS_FIN_WAIT_1         6       /* have closed, sent fin */
 132 #define TCPS_CLOSING            7       /* closed xchd FIN; await FIN ACK */
 133 #define TCPS_LAST_ACK           8       /* had fin and close; await FIN ACK */
 134 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
 135 #define TCPS_FIN_WAIT_2         9       /* have closed, fin is acked */
 136 #define TCPS_TIME_WAIT          10      /* in 2*msl quiet wait after close */
 137
 138 #define TCPS_HAVERCVDSYN(s)     ((s) >= TCPS_SYN_RECEIVED)
 139 #define TCPS_HAVEESTABLISHED(s) ((s) >= TCPS_ESTABLISHED)
 140 #define TCPS_HAVERCVDFIN(s)     ((s) >= TCPS_TIME_WAIT)
 141
 142 /*
 143  * TCP sequence numbers are 32 bit integers operated
 144  * on with modular arithmetic.  These macros can be
 145  * used to compare such integers.
 146  */
 147 #define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
 148 #define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
 149 #define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
 150 #define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
 151
 152 /*
 153  * Macros to initialize tcp sequence numbers for
 154  * send and receive from initial send and receive
 155  * sequence numbers.
 156  */
 157 #define tcp_rcvseqinit(tp) \
 158      (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
 159
 160 #define tcp_sendseqinit(tp) \
 161     (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = (tp)->iss
 162
 163 #define TCP_ISSINCR     (125*1024)      /* increment for tcp_iss each second */
 164
 165 extern tcp_seq tcp_iss;                /* tcp initial send seq # */
 166
 167 extern char *tcpstates[];
 168
 169 #endif