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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 "../../messages.h"
  41.  
  42. #include "packet.h"
  43.  
  44. /** Packet integrity check magic value.
  45.  */
  46. #define PACKET_MAGIC_VALUE  0x11227788
  47.  
  48. /** Packet header.
  49.  */
  50. struct packet{
  51.     /** Packet identifier.
  52.      */
  53.     packet_id_t     packet_id;
  54.     /** Packet queue sorting value.
  55.      *  The packet queue is sorted the ascending order.
  56.      */
  57.     int             order;
  58.     /** Packet metric.
  59.      */
  60.     size_t          metric;
  61.     /** Previous packet in the queue.
  62.      */
  63.     packet_id_t     previous;
  64.     /** Next packet in the queue.
  65.      */
  66.     packet_id_t     next;
  67.     /** Total length of the packet.
  68.      *  Contains the header, the addresses and the data of the packet.
  69.      *  Corresponds to the mapped sharable memory block.
  70.      */
  71.     size_t          length;
  72.     /** Stored source and destination addresses length.
  73.      */
  74.     size_t          addr_len;
  75.     /** Souce address offset in bytes from the beginning of the packet header.
  76.      */
  77.     size_t          src_addr;
  78.     /** Destination address offset in bytes from the beginning of the packet header.
  79.      */
  80.     size_t          dest_addr;
  81.     /** Reserved data prefix length in bytes.
  82.      */
  83.     size_t          max_prefix;
  84.     /** Reserved content length in bytes.
  85.      */
  86.     size_t          max_content;
  87.     /** Actual data start offset in bytes from the beginning of the packet header.
  88.      */
  89.     size_t          data_start;
  90.     /** Actual data end offset in bytes from the beginning of the packet header.
  91.      */
  92.     size_t          data_end;
  93.     /** Integrity check magic value.
  94.      */
  95.     int             magic_value;
  96. };
  97.  
  98. /** Returns whether the packet is valid.
  99.  *  @param packet The packet to be checked. Input parameter.
  100.  *  @returns true if the packet is not NULL and the magic value is correct.
  101.  *  @returns false otherwise.
  102.  */
  103. static inline int   packet_is_valid( const packet_t packet ){
  104.     return packet && ( packet->magic_value == PACKET_MAGIC_VALUE );
  105. }
  106.  
  107. #endif
  108.  
  109. /** @}
  110.  */
  111.