text: /****************************************************************************
   *******                                                              *******
   *******            P A C K E T   H E A D E R   F I L E
   *******                                                              *******
   ****************************************************************************
  
   Author  : Ian Nandhra / Jeremy Rolls
   Date    :
  
   *
   *  (C) 1990 - 2000 Specialix International Ltd., Byfleet, Surrey, UK.
   *
   *      This program is free software; you can redistribute it and/or modify
   *      it under the terms of the GNU General Public License as published by
   *      the Free Software Foundation; either version 2 of the License, or
   *      (at your option) any later version.
   *
   *      This program is distributed in the hope that it will be useful,
   *      but WITHOUT ANY WARRANTY; without even the implied warranty of
   *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *      GNU General Public License for more details.
   *
   *      You should have received a copy of the GNU General Public License
   *      along with this program; if not, write to the Free Software
   *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  
   Version : 0.01
  
  
                              Mods
   ----------------------------------------------------------------------------
    Date     By                Description
   ----------------------------------------------------------------------------
  
   ***************************************************************************/
  
  #ifndef _pkt_h
  #define _pkt_h 1
  
  
  #ifdef SCCS_LABELS
  #ifndef lint
  /* static char *_rio_pkt_h_sccs = "@(#)pkt.h	1.8"; */
  #endif
  #endif
  
  #define MAX_TTL         0xf
  #define PKT_CMD_BIT     ((ushort) 0x080)
  #define PKT_CMD_DATA    ((ushort) 0x080)
  
  #define PKT_ACK         ((ushort) 0x040)
  
  #define PKT_TGL         ((ushort) 0x020)
  
  #define PKT_LEN_MASK    ((ushort) 0x07f)
  
  #define DATA_WNDW       ((ushort) 0x10)
  #define PKT_TTL_MASK    ((ushort) 0x0f)
  
  #define PKT_MAX_DATA_LEN   72
  
  #define PKT_LENGTH         sizeof(struct PKT)
  #define SYNC_PKT_LENGTH    (PKT_LENGTH + 4)
  
  #define CONTROL_PKT_LEN_MASK PKT_LEN_MASK
  #define CONTROL_PKT_CMD_BIT  PKT_CMD_BIT
  #define CONTROL_PKT_ACK (PKT_ACK << 8)
  #define CONTROL_PKT_TGL (PKT_TGL << 8)
  #define CONTROL_PKT_TTL_MASK (PKT_TTL_MASK << 8)
  #define CONTROL_DATA_WNDW  (DATA_WNDW << 8)
  
  struct PKT    {
  #ifdef INKERNEL
                     BYTE    dest_unit ;    /* Destination Unit Id */
                     BYTE    dest_port ;    /* Destination POrt */
                     BYTE    src_unit ;     /* Source Unit Id */
                     BYTE    src_port ;     /* Source POrt */
  #else
                     union       
                     {
                         ushort destination;         /* Complete destination */
                         struct
                         {
                             unsigned char unit;     /* Destination unit */
                             unsigned char port;     /* Destination port */
                         } s1;
                     } u1;
                     union       
                     {
                         ushort source;              /* Complete source */
                         struct
                         {
                             unsigned char unit;     /* Source unit */
                             unsigned char port;     /* Source port */
                         } s2;
                     } u2;
  #endif
  #ifdef INKERNEL
                     BYTE len ;
                     BYTE control;
  #else
                     union
                     {
                          ushort      control;
                          struct
                          {
                              unsigned char len;
                              unsigned char control;
                          } s3;
                      } u3;
  #endif
                     BYTE    data[PKT_MAX_DATA_LEN] ;     
                                                     /* Actual data :-) */
                     WORD  csum ;                  /* C-SUM */
                 } ;
  #endif
  
  /*********** end of file ***********/
  
  
  