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82 lines
2.5 KiB
C
82 lines
2.5 KiB
C
/*
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* Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup net_inet_csum Internet Checksum
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* @ingroup net
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* @brief Provides a function to calculate the Internet Checksum
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* @{
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*
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* @file
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* @brief Internet Checksum definitions
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*
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* @author Martine Lenders <mlenders@inf.fu-berlin.de>
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*/
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#ifndef NET_INET_CSUM_H
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#define NET_INET_CSUM_H
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#include <inttypes.h>
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Calculates the unnormalized Internet Checksum of @p buf, where the
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* buffer provides a slice of the full checksum domain, calculated in order.
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*
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* @see <a href="https://tools.ietf.org/html/rfc1071">
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* RFC 1071
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* </a>
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*
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* @details The Internet Checksum is not normalized (i. e. its 1's complement
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* was not taken of the result) to use it for further calculation.
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* This function handles padding an odd number of bytes across the full domain.
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*
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* @param[in] sum An initial value for the checksum.
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* @param[in] buf A buffer.
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* @param[in] len Length of @p buf in byte.
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* @param[in] accum_len Accumulated length of checksum domain that has already
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* been checksummed.
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*
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* @return The unnormalized Internet Checksum of @p buf.
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*/
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uint16_t inet_csum_slice(uint16_t sum, const uint8_t *buf, uint16_t len, size_t accum_len);
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/**
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* @brief Calculates the unnormalized Internet Checksum of @p buf, where the
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* buffer provides a standalone domain for the checksum.
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*
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* @see <a href="https://tools.ietf.org/html/rfc1071">
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* RFC 1071
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* </a>
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*
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* @details The Internet Checksum is not normalized (i. e. its 1's complement
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* was not taken of the result) to use it for further calculation.
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* This function, rather than inet_csum_slice(), has been used historically
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* when we are not concerned with padding for an odd number of bytes.
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*
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*
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* @param[in] sum An initial value for the checksum.
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* @param[in] buf A buffer.
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* @param[in] len Length of @p buf in byte.
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*
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* @return The unnormalized Internet Checksum of @p buf.
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*/
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static inline uint16_t inet_csum(uint16_t sum, const uint8_t *buf, uint16_t len) {
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return inet_csum_slice(sum, buf, len, 0);
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* NET_INET_CSUM_H */
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/** @} */
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