root/net/tcp/tcp.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. before
  2. after
  3. between
  4. tcp_connected

   1 /* tcp.h */
   2 /*
   3     Copyright (C) 1992  Ross Biro
   4 
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2, or (at your option)
   8     any later version.
   9 
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14 
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 
  18 
  19     The Author may be reached as bir7@leland.stanford.edu or
  20     C/O Department of Mathematics; Stanford University; Stanford, CA 94305
  21 */
  22 /* $Id: tcp.h,v 0.8.4.6 1992/12/12 19:25:04 bir7 Exp $ */
  23 /* $Log: tcp.h,v $
  24  * Revision 0.8.4.6  1992/12/12  19:25:04  bir7
  25  * Fixed anti-memory Leak in shutdown.
  26  *
  27  * Revision 0.8.4.5  1992/12/12  01:50:49  bir7
  28  * Fixed several bugs including half-duplex connections.
  29  *
  30  * Revision 0.8.4.4  1992/12/08  20:49:15  bir7
  31  * Fixed minor bugs and checked out MSS.
  32  *
  33  * Revision 0.8.4.3  1992/12/06  23:29:59  bir7
  34  * Added support for mss and half completed packets.  Also added
  35  * support for shrinking windows.
  36  *
  37  * Revision 0.8.4.2  1992/12/03  19:54:12  bir7
  38  * Added paranoid queue checking.
  39  *
  40  * Revision 0.8.4.1  1992/11/10  00:17:18  bir7
  41  * version change only.
  42  *
  43  * Revision 0.8.3.2  1992/11/10  00:14:47  bir7
  44  * Changed malloc to kmalloc and added Id and Log
  45  *
  46  */
  47 
  48 #ifndef _TCP_TCP_H
  49 #define _TCP_TCP_H
  50 
  51 struct tcp_header
  52 {
  53   unsigned short source;
  54   unsigned short dest;
  55   unsigned long seq;
  56   unsigned long ack_seq;
  57   unsigned short res1:4, doff:4, fin:1, syn:1, rst:1, psh:1,
  58                  ack:1, urg:1,res2:2;
  59   unsigned short window;
  60   unsigned short check;
  61   unsigned short urg_ptr;
  62 };
  63 
  64 enum {
  65   TCP_ESTABLISHED=1,
  66   TCP_SYN_SENT,
  67   TCP_SYN_RECV,
  68 #if 0
  69   TCP_CLOSING, /* not a valid state, just a seperator so we can use
  70                   < tcp_closing or > tcp_closing for checks. */
  71 #endif
  72   TCP_FIN_WAIT1,
  73   TCP_FIN_WAIT2,
  74   TCP_TIME_WAIT,
  75   TCP_CLOSE,
  76   TCP_CLOSE_WAIT,
  77   TCP_LAST_ACK,
  78   TCP_LISTEN
  79 };
  80 
  81 #define MAX_SYN_SIZE 44 + sizeof (struct sk_buff) + MAX_HEADER
  82 #define MAX_FIN_SIZE 40 + sizeof (struct sk_buff) + MAX_HEADER
  83 #define MAX_ACK_SIZE 40 + sizeof (struct sk_buff) + MAX_HEADER
  84 #define MAX_RESET_SIZE 40 + sizeof (struct sk_buff) + MAX_HEADER
  85 #define MAX_WINDOW  12000
  86 #define MIN_WINDOW   2048
  87 #define MAX_ACK_BACKLOG 2
  88 #define MIN_WRITE_SPACE 2048
  89 #define TCP_WINDOW_DIFF 2048
  90 
  91 #define TCP_RETR1      10       /* this is howmany retries it does
  92                                    before it tries to figure out
  93                                    if the gateway is down. */
  94 
  95 #define TCP_RETR2      25       /* this should take at least
  96                                    90 minutes to time out. */
  97 
  98 
  99 #define TCP_TIMEOUT_LEN 720000 /* should be about 2 hrs. */
 100 #define TCP_TIMEWAIT_LEN 6000 /* How long to wait to sucessfully 
 101                                  close the socket, about 60 seconds. */
 102 #define TCP_ACK_TIME 35 /* time to delay before sending an ack. */
 103 #define TCP_DONE_TIME 250 /* maximum time to wait before actually destroying
 104                              a socket. */
 105 #define TCP_WRITE_TIME 100 /* initial time to wait for an ack,
 106                               after last transmit. */
 107 #define TCP_CONNECT_TIME 200 /* time to retransmit first syn. */
 108 #define TCP_SYN_RETRIES 30 /* number of times to retry openning a connection.
 109                               */
 110 #define TCP_PROBEWAIT_LEN 250 /* time to wait between probes when I've got
 111                                  something to write and there is no window. */
 112 
 113 #define TCP_NO_CHECK 0 /* turn to one if you want the default to be no
 114                           checksum . */
 115 
 116 void print_th (struct tcp_header *);
 117 #define HEADER_SIZE 64 /* Maximum header size we need to deal with. */
 118 
 119 #define TCP_WRITE_QUEUE_MAGIC 0xa5f23477
 120 
 121  /* this next routines deal with comparing 32 bit unsigned ints and
 122     worry about wrap around. The general strategy is to do a normal
 123     compare so long as neither of the numbers is within 4k of wrapping.
 124     Otherwise we must check for the wrap. */
 125 
 126  static inline int
 127  before (unsigned long seq1, unsigned long seq2)
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 128  {
 129    /* this inequality is strict. */
 130    if (seq1 == seq2) return (0);
 131    if (seq1 < seq2) 
 132      {
 133        if ((unsigned long)seq2-(unsigned long)seq1 < 32767UL) 
 134          {
 135            return (1);
 136          }
 137        else
 138          {
 139            return (0);
 140          }
 141      }
 142    /* now we know seq1 > seq2.  So all we need to do is check to see
 143       if seq1 has wrapped. */
 144    if (seq2 < 4096UL && seq1 > (0xffffffUL - 4096UL))
 145      {
 146        return (1);
 147      }
 148    return (0);
 149 
 150  }
 151 
 152  static inline int
 153  after (unsigned long seq1, unsigned long seq2)
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 154  {
 155    return (before (seq2, seq1));
 156  }
 157 
 158  /* is s2<=s1<=s3 ? */
 159  static inline int
 160  between (unsigned long seq1, unsigned long seq2, unsigned long seq3)
     /* [previous][next][first][last][top][bottom][index][help] */
 161  {
 162    return (after (seq1+1, seq2) && before (seq1, seq3+1));
 163  }
 164 
 165 static inline const int
 166 tcp_connected (const int state)
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 167 {
 168   return (state == TCP_ESTABLISHED || state == TCP_CLOSE_WAIT ||
 169           state == TCP_FIN_WAIT1   || state == TCP_FIN_WAIT2);
 170 }
 171 
 172 #endif

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