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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 udp
  30.  *  @{
  31.  */
  32.  
  33. /** @file
  34.  *  UDP header definition.
  35.  *  Names according to the linux src/include/linux/udp.h header file.
  36.  */
  37.  
  38. #ifndef __NET_UDP_HEADER_H__
  39. #define __NET_UDP_HEADER_H__
  40.  
  41. #include <sys/types.h>
  42.  
  43. /** Type definition of the user datagram header.
  44.  *  @see udp_header
  45.  */
  46. typedef struct udp_header   udp_header_t;
  47.  
  48. /** Type definition of the user datagram header pointer.
  49.  *  @see udp_header
  50.  */
  51. typedef udp_header_t *      udp_header_ref;
  52.  
  53. /** User datagram header.
  54.  */
  55. struct udp_header{
  56.     /** Source Port is an optional field, when meaningful, it indicates the port of the sending process, and may be assumed to be the port to which a reply should be addressed in the absence of any other information.
  57.      *  If not used, a value of zero is inserted.
  58.      */
  59.     uint16_t    source;
  60.     /** Destination port has a meaning within the context of a particular internet destination address.
  61.      */
  62.     uint16_t    dest;
  63.     /** Length is the length in octets of this user datagram including this header and the data.
  64.      *  This means the minimum value of the length is eight.
  65.      */
  66.     uint16_t    len;
  67.     /** Checksum is the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded with zero octets at the end (if necessary) to make a multiple of two octets.
  68.      *  The pseudo header conceptually prefixed to the UDP header contains the source address, the destination address, the protocol, and the UDP length.
  69.      *  This information gives protection against misrouted datagrams.
  70.      *  If the computed checksum is zero, it is transmitted as all ones (the equivalent in one's complement arithmetic).
  71.      *  An all zero transmitted checksum value means that the transmitter generated no checksum (for debugging or for higher level protocols that don't care).
  72.      */
  73.     uint16_t    check;
  74. } __attribute__ ((packed));
  75.  
  76. #endif
  77.  
  78. /** @}
  79.  */
  80.