wsutil/crc32.h

   1 /** @file
   2  * Declaration of CRC-32 routine and table
   3  *
   4  * Wireshark - Network traffic analyzer
   5  * By Gerald Combs <gerald@wireshark.org>
   6  * Copyright 1998 Gerald Combs
   7  *
   8  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #ifndef __CRC32_H__
  12 #define __CRC32_H__
  13
  14 #include <wireshark.h>
  15
  16 #ifdef __cplusplus
  17 extern "C" {
  18 #endif /* __cplusplus */
  19
  20 #define CRC32_CCITT_SEED 0xFFFFFFFF
  21 #define CRC32C_PRELOAD   0xffffffff
  22 #define CRC32_MPEG2_SEED 0xFFFFFFFF
  23
  24 /*
  25  * Byte swap fix contributed by Dave Wysochanski <davidw@netapp.com>.
  26  */
  27 #define CRC32C_SWAP(crc32c_value)                               \
  28         (((crc32c_value & 0xff000000) >> 24)    |       \
  29          ((crc32c_value & 0x00ff0000) >>  8)    |       \
  30          ((crc32c_value & 0x0000ff00) <<  8)    |       \
  31          ((crc32c_value & 0x000000ff) << 24))
  32
  33 /** Lookup the crc value in the crc32_ccitt_table
  34  @param pos Position in the table. */
  35 WS_DLL_PUBLIC uint32_t crc32_ccitt_table_lookup (unsigned char pos);
  36
  37 /** Lookup the crc value in the crc32c_table
  38  @param pos Position in the table. */
  39 WS_DLL_PUBLIC uint32_t crc32c_table_lookup (unsigned char pos);
  40
  41 /** Compute CRC32C checksum of a buffer of data.
  42  @param buf The buffer containing the data.
  43  @param len The number of bytes to include in the computation.
  44  @param crc The preload value for the CRC32C computation.
  45  @return The CRC32C checksum. */
  46 WS_DLL_PUBLIC uint32_t crc32c_calculate(const void *buf, int len, uint32_t crc);
  47
  48 /** Compute CRC32C checksum of a buffer of data without swapping seed crc
  49  or completed checksum
  50  @param buf The buffer containing the data.
  51  @param len The number of bytes to include in the computation.
  52  @param crc The preload value for the CRC32C computation.
  53  @return The CRC32C checksum. */
  54 WS_DLL_PUBLIC uint32_t crc32c_calculate_no_swap(const void *buf, int len, uint32_t crc);
  55
  56 /** Compute CRC32 CCITT checksum of a buffer of data.
  57  @param buf The buffer containing the data.
  58  @param len The number of bytes to include in the computation.
  59  @return The CRC32 CCITT checksum. */
  60 WS_DLL_PUBLIC uint32_t crc32_ccitt(const uint8_t *buf, unsigned len);
  61
  62 /** Compute CRC32 CCITT checksum of a buffer of data.  If computing the
  63  *  checksum over multiple buffers and you want to feed the partial CRC32
  64  *  back in, remember to take the 1's complement of the partial CRC32 first.
  65  @param buf The buffer containing the data.
  66  @param len The number of bytes to include in the computation.
  67  @param seed The seed to use.
  68  @return The CRC32 CCITT checksum (using the given seed). */
  69 WS_DLL_PUBLIC uint32_t crc32_ccitt_seed(const uint8_t *buf, unsigned len, uint32_t seed);
  70
  71 /** Compute MPEG-2 CRC32 checksum of a buffer of data.
  72  @param buf The buffer containing the data.
  73  @param len The number of bytes to include in the computation.
  74  @param seed The seed to use.
  75  @return The CRC32 MPEG-2 checksum (using the given seed). */
  76 WS_DLL_PUBLIC uint32_t crc32_mpeg2_seed(const uint8_t *buf, unsigned len, uint32_t seed);
  77
  78 /** Computes CRC32 checksum for the given data with the polynom 0x0AA725CF using
  79  *  precompiled CRC table
  80  * @param buf a pointer to a buffer of the given length
  81  * @param len the length of the given buffer
  82  * @param seed The seed to use.
  83  * @return the CRC32 checksum for the buffer
  84  */
  85 WS_DLL_PUBLIC uint32_t crc32_0x0AA725CF_seed(const uint8_t *buf, unsigned len, uint32_t seed);
  86
  87 /** Computes CRC32 checksum for the given data with the polynom 0x5D6DCB using
  88  *  precompiled CRC table
  89  * @param buf a pointer to a buffer of the given length
  90  * @param len the length of the given buffer
  91  * @param seed The seed to use.
  92  * @return the CRC32 checksum for the buffer
  93  */
  94 WS_DLL_PUBLIC uint32_t crc32_0x5D6DCB_seed(const uint8_t *buf, unsigned len, uint32_t seed);
  95
  96 WS_DLL_PUBLIC int Dot11DecryptWepDecrypt(
  97         const unsigned char *seed,
  98         const size_t seed_len,
  99         unsigned char *cypher_text,
 100         const size_t data_len);
 101
 102 #ifdef __cplusplus
 103 }
 104 #endif /* __cplusplus */
 105
 106 #endif /* crc32.h */