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. 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.h       8.1 (Berkeley) 6/10/93
  30  * tcp.h,v 1.3 1994/08/21 05:27:34 paul Exp
  31  */
  32
  33 #ifndef _TCP_H_
  34 #define _TCP_H_
  35
  36 typedef uint32_t tcp_seq;
  37
  38 #define      PR_SLOWHZ       2               /* 2 slow timeouts per second (approx) */
  39 #define      PR_FASTHZ       5               /* 5 fast timeouts per second (not important) */
  40
  41 #define TCP_SNDSPACE 8192
  42 #define TCP_RCVSPACE 8192
  43
  44 /*
  45  * TCP header.
  46  * Per RFC 793, September, 1981.
  47  */
  48 struct tcphdr {
  49         uint16_t th_sport;              /* source port */
  50         uint16_t th_dport;              /* destination port */
  51         tcp_seq th_seq;                 /* sequence number */
  52         tcp_seq th_ack;                 /* acknowledgement number */
  53 #ifdef HOST_WORDS_BIGENDIAN
  54         u_int   th_off:4,               /* data offset */
  55                 th_x2:4;                /* (unused) */
  56 #else
  57         u_int   th_x2:4,                /* (unused) */
  58                 th_off:4;               /* data offset */
  59 #endif
  60         uint8_t th_flags;
  61 #define TH_FIN  0x01
  62 #define TH_SYN  0x02
  63 #define TH_RST  0x04
  64 #define TH_PUSH 0x08
  65 #define TH_ACK  0x10
  66 #define TH_URG  0x20
  67         uint16_t th_win;                /* window */
  68         uint16_t th_sum;                /* checksum */
  69         uint16_t th_urp;                /* urgent pointer */
  70 };
  71
  72 #include "tcp_var.h"
  73
  74 #define TCPOPT_EOL              0
  75 #define TCPOPT_NOP              1
  76 #define TCPOPT_MAXSEG           2
  77 #define    TCPOLEN_MAXSEG               4
  78 #define TCPOPT_WINDOW           3
  79 #define    TCPOLEN_WINDOW               3
  80 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
  81 #define    TCPOLEN_SACK_PERMITTED       2
  82 #define TCPOPT_SACK             5               /* Experimental */
  83 #define TCPOPT_TIMESTAMP        8
  84 #define    TCPOLEN_TIMESTAMP            10
  85 #define    TCPOLEN_TSTAMP_APPA          (TCPOLEN_TIMESTAMP+2) /* appendix A */
  86
  87 #define TCPOPT_TSTAMP_HDR       \
  88     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
  89
  90 /*
  91  * Default maximum segment size for TCP.
  92  * With an IP MSS of 576, this is 536,
  93  * but 512 is probably more convenient.
  94  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
  95  *
  96  * We make this 1460 because we only care about Ethernet in the qemu context.
  97  */
  98 #define TCP_MSS 1460
  99
 100 #define TCP_MAXWIN      65535   /* largest value for (unscaled) window */
 101
 102 #define TCP_MAX_WINSHIFT        14      /* maximum window shift */
 103
 104 /*
 105  * User-settable options (used with setsockopt).
 106  *
 107  * We don't use the system headers on unix because we have conflicting
 108  * local structures. We can't avoid the system definitions on Windows,
 109  * so we undefine them.
 110  */
 111 #undef TCP_NODELAY
 112 #define TCP_NODELAY     0x01    /* don't delay send to coalesce packets */
 113 #undef TCP_MAXSEG
 114
 115 /*
 116  * TCP FSM state definitions.
 117  * Per RFC793, September, 1981.
 118  */
 119
 120 #define TCP_NSTATES     11
 121
 122 #define TCPS_CLOSED             0       /* closed */
 123 #define TCPS_LISTEN             1       /* listening for connection */
 124 #define TCPS_SYN_SENT           2       /* active, have sent syn */
 125 #define TCPS_SYN_RECEIVED       3       /* have send and received syn */
 126 /* states < TCPS_ESTABLISHED are those where connections not established */
 127 #define TCPS_ESTABLISHED        4       /* established */
 128 #define TCPS_CLOSE_WAIT         5       /* rcvd fin, waiting for close */
 129 /* states > TCPS_CLOSE_WAIT are those where user has closed */
 130 #define TCPS_FIN_WAIT_1         6       /* have closed, sent fin */
 131 #define TCPS_CLOSING            7       /* closed xchd FIN; await FIN ACK */
 132 #define TCPS_LAST_ACK           8       /* had fin and close; await FIN ACK */
 133 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
 134 #define TCPS_FIN_WAIT_2         9       /* have closed, fin is acked */
 135 #define TCPS_TIME_WAIT          10      /* in 2*msl quiet wait after close */
 136
 137 #define TCPS_HAVERCVDSYN(s)     ((s) >= TCPS_SYN_RECEIVED)
 138 #define TCPS_HAVEESTABLISHED(s) ((s) >= TCPS_ESTABLISHED)
 139 #define TCPS_HAVERCVDFIN(s)     ((s) >= TCPS_TIME_WAIT)
 140
 141 /*
 142  * TCP sequence numbers are 32 bit integers operated
 143  * on with modular arithmetic.  These macros can be
 144  * used to compare such integers.
 145  */
 146 #define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
 147 #define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
 148 #define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
 149 #define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
 150
 151 /*
 152  * Macros to initialize tcp sequence numbers for
 153  * send and receive from initial send and receive
 154  * sequence numbers.
 155  */
 156 #define tcp_rcvseqinit(tp) \
 157      (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
 158
 159 #define tcp_sendseqinit(tp) \
 160     (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = (tp)->iss
 161
 162 #define TCP_ISSINCR     (125*1024)      /* increment for tcp_iss each second */
 163
 164 #endif