slirp/src/tcp.h

   1 /* SPDX-License-Identifier: BSD-3-Clause */
   2 /*
   3  * Copyright (c) 1982, 1986, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the University nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  *      @(#)tcp.h       8.1 (Berkeley) 6/10/93
  31  * tcp.h,v 1.3 1994/08/21 05:27:34 paul Exp
  32  */
  33
  34 #ifndef TCP_H
  35 #define TCP_H
  36
  37 #include <glib.h>
  38
  39 typedef uint32_t tcp_seq;
  40
  41 #define      PR_SLOWHZ       2               /* 2 slow timeouts per second (approx) */
  42 #define      PR_FASTHZ       5               /* 5 fast timeouts per second (not important) */
  43
  44 #define TCP_SNDSPACE 8192
  45 #define TCP_RCVSPACE 8192
  46
  47 /*
  48  * TCP header.
  49  * Per RFC 793, September, 1981.
  50  */
  51 #define tcphdr slirp_tcphdr
  52 struct tcphdr {
  53         uint16_t th_sport;              /* source port */
  54         uint16_t th_dport;              /* destination port */
  55         tcp_seq th_seq;                 /* sequence number */
  56         tcp_seq th_ack;                 /* acknowledgement number */
  57 #if G_BYTE_ORDER == G_BIG_ENDIAN
  58         uint8_t th_off:4,               /* data offset */
  59                 th_x2:4;                /* (unused) */
  60 #else
  61         uint8_t th_x2:4,                /* (unused) */
  62                 th_off:4;               /* data offset */
  63 #endif
  64         uint8_t th_flags;
  65         uint16_t th_win;                /* window */
  66         uint16_t th_sum;                /* checksum */
  67         uint16_t th_urp;                /* urgent pointer */
  68 };
  69
  70 #include "tcp_var.h"
  71
  72 #ifndef TH_FIN
  73 #define TH_FIN  0x01
  74 #define TH_SYN  0x02
  75 #define TH_RST  0x04
  76 #define TH_PUSH 0x08
  77 #define TH_ACK  0x10
  78 #define TH_URG  0x20
  79 #endif
  80
  81 #ifndef TCPOPT_EOL
  82 #define TCPOPT_EOL              0
  83 #define TCPOPT_NOP              1
  84 #define TCPOPT_MAXSEG           2
  85 #define TCPOPT_WINDOW           3
  86 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
  87 #define TCPOPT_SACK             5               /* Experimental */
  88 #define TCPOPT_TIMESTAMP        8
  89
  90 #define TCPOPT_TSTAMP_HDR       \
  91     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
  92 #endif
  93
  94 #ifndef TCPOLEN_MAXSEG
  95 #define    TCPOLEN_MAXSEG               4
  96 #define    TCPOLEN_WINDOW               3
  97 #define    TCPOLEN_SACK_PERMITTED       2
  98 #define    TCPOLEN_TIMESTAMP            10
  99 #define    TCPOLEN_TSTAMP_APPA          (TCPOLEN_TIMESTAMP+2) /* appendix A */
 100 #endif
 101
 102 /*
 103  * Default maximum segment size for TCP.
 104  * With an IP MSS of 576, this is 536,
 105  * but 512 is probably more convenient.
 106  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 107  *
 108  * We make this 1460 because we only care about Ethernet in the qemu context.
 109  */
 110 #undef TCP_MSS
 111 #define TCP_MSS 1460
 112 #undef TCP6_MSS
 113 #define TCP6_MSS 1440
 114
 115 #undef TCP_MAXWIN
 116 #define TCP_MAXWIN      65535   /* largest value for (unscaled) window */
 117
 118 #undef TCP_MAX_WINSHIFT
 119 #define TCP_MAX_WINSHIFT        14      /* maximum window shift */
 120
 121 /*
 122  * User-settable options (used with setsockopt).
 123  *
 124  * We don't use the system headers on unix because we have conflicting
 125  * local structures. We can't avoid the system definitions on Windows,
 126  * so we undefine them.
 127  */
 128 #undef TCP_NODELAY
 129 #define TCP_NODELAY     0x01    /* don't delay send to coalesce packets */
 130 #undef TCP_MAXSEG
 131
 132 /*
 133  * TCP FSM state definitions.
 134  * Per RFC793, September, 1981.
 135  */
 136
 137 #define TCP_NSTATES     11
 138
 139 #define TCPS_CLOSED             0       /* closed */
 140 #define TCPS_LISTEN             1       /* listening for connection */
 141 #define TCPS_SYN_SENT           2       /* active, have sent syn */
 142 #define TCPS_SYN_RECEIVED       3       /* have send and received syn */
 143 /* states < TCPS_ESTABLISHED are those where connections not established */
 144 #define TCPS_ESTABLISHED        4       /* established */
 145 #define TCPS_CLOSE_WAIT         5       /* rcvd fin, waiting for close */
 146 /* states > TCPS_CLOSE_WAIT are those where user has closed */
 147 #define TCPS_FIN_WAIT_1         6       /* have closed, sent fin */
 148 #define TCPS_CLOSING            7       /* closed xchd FIN; await FIN ACK */
 149 #define TCPS_LAST_ACK           8       /* had fin and close; await FIN ACK */
 150 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
 151 #define TCPS_FIN_WAIT_2         9       /* have closed, fin is acked */
 152 #define TCPS_TIME_WAIT          10      /* in 2*msl quiet wait after close */
 153
 154 #define TCPS_HAVERCVDSYN(s)     ((s) >= TCPS_SYN_RECEIVED)
 155 #define TCPS_HAVEESTABLISHED(s) ((s) >= TCPS_ESTABLISHED)
 156 #define TCPS_HAVERCVDFIN(s)     ((s) >= TCPS_TIME_WAIT)
 157
 158 /*
 159  * TCP sequence numbers are 32 bit integers operated
 160  * on with modular arithmetic.  These macros can be
 161  * used to compare such integers.
 162  */
 163 #define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
 164 #define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
 165 #define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
 166 #define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
 167
 168 /*
 169  * Macros to initialize tcp sequence numbers for
 170  * send and receive from initial send and receive
 171  * sequence numbers.
 172  */
 173 #define tcp_rcvseqinit(tp) \
 174      (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
 175
 176 #define tcp_sendseqinit(tp) \
 177     (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = (tp)->iss
 178
 179 #define TCP_ISSINCR     (125*1024)      /* increment for tcp_iss each second */
 180
 181 #endif