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  1. /*
  2.  * Copyright (c) 2009 Lukas Mejdrech
  3.  * 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.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - 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.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup packet
  30.  *  @{
  31.  */
  32.  
  33. /** @file
  34.  *  Packet header.
  35.  */
  36.  
  37. #ifndef __NET_PACKET_HEADER_H__
  38. #define __NET_PACKET_HEADER_H__
  39.  
  40. #include "packet.h"
  41.  
  42. /** Returns the actual packet data length.
  43.  *  @param[in] header The packet header.
  44.  */
  45. #define PACKET_DATA_LENGTH( header )        (( header )->data_end - ( header )->data_start )
  46.  
  47. /** Returns the maximum packet address length.
  48.  *  @param[in] header The packet header.
  49.  */
  50. #define PACKET_MAX_ADDRESS_LENGTH( header )     (( header )->dest_addr - ( header )->src_addr )
  51.  
  52. /** Returns the minimum packet suffix.
  53.  *  @param[in] header The packet header.
  54.  */
  55. #define PACKET_MIN_SUFFIX( header )     (( header )->length - ( header )->data_start - ( header )->max_content )
  56.  
  57. /** Packet integrity check magic value.
  58.  */
  59. #define PACKET_MAGIC_VALUE  0x11227788
  60.  
  61. /** Packet header.
  62.  */
  63. struct packet{
  64.     /** Packet identifier.
  65.      */
  66.     packet_id_t     packet_id;
  67.     /** Packet queue sorting value.
  68.      *  The packet queue is sorted the ascending order.
  69.      */
  70.     size_t          order;
  71.     /** Packet metric.
  72.      */
  73.     size_t          metric;
  74.     /** Previous packet in the queue.
  75.      */
  76.     packet_id_t     previous;
  77.     /** Next packet in the queue.
  78.      */
  79.     packet_id_t     next;
  80.     /** Total length of the packet.
  81.      *  Contains the header, the addresses and the data of the packet.
  82.      *  Corresponds to the mapped sharable memory block.
  83.      */
  84.     size_t          length;
  85.     /** Stored source and destination addresses length.
  86.      */
  87.     size_t          addr_len;
  88.     /** Souce address offset in bytes from the beginning of the packet header.
  89.      */
  90.     size_t          src_addr;
  91.     /** Destination address offset in bytes from the beginning of the packet header.
  92.      */
  93.     size_t          dest_addr;
  94.     /** Reserved data prefix length in bytes.
  95.      */
  96.     size_t          max_prefix;
  97.     /** Reserved content length in bytes.
  98.      */
  99.     size_t          max_content;
  100.     /** Actual data start offset in bytes from the beginning of the packet header.
  101.      */
  102.     size_t          data_start;
  103.     /** Actual data end offset in bytes from the beginning of the packet header.
  104.      */
  105.     size_t          data_end;
  106.     /** Integrity check magic value.
  107.      */
  108.     int             magic_value;
  109. };
  110.  
  111. /** Returns whether the packet is valid.
  112.  *  @param[in] packet The packet to be checked.
  113.  *  @returns true if the packet is not NULL and the magic value is correct.
  114.  *  @returns false otherwise.
  115.  */
  116. static inline int   packet_is_valid( const packet_t packet ){
  117.     return packet && ( packet->magic_value == PACKET_MAGIC_VALUE );
  118. }
  119.  
  120. #endif
  121.  
  122. /** @}
  123.  */
  124.