wireshark/wsutil/crc6.c

84 lines
3.1 KiB
C

/*
* crc6.c
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
Patch by Ross Jacobs <rossbjacobs@gmail.com>:
Fixed CRC6 0x6F lookup table + function per Wireshark bug 14875
*/
#include "config.h"
#include <glib.h>
#include "crc6.h"
/**
* Functions and types for CRC checks.
*
* Generated on Wed Jan 2 2019,
* by pycrc v0.9.1, http://www.tty1.net/pycrc/
* using the configuration:
* Width = 6
* Poly = 0x6f
* XorIn = 0
* ReflectIn = False
* XorOut = 0
* ReflectOut = False
*/
static const guint8 crc6_table[256] = {
0x00, 0x2f, 0x31, 0x1e, 0x0d, 0x22, 0x3c, 0x13, 0x1a, 0x35, 0x2b, 0x04, 0x17, 0x38, 0x26, 0x09,
0x34, 0x1b, 0x05, 0x2a, 0x39, 0x16, 0x08, 0x27, 0x2e, 0x01, 0x1f, 0x30, 0x23, 0x0c, 0x12, 0x3d,
0x07, 0x28, 0x36, 0x19, 0x0a, 0x25, 0x3b, 0x14, 0x1d, 0x32, 0x2c, 0x03, 0x10, 0x3f, 0x21, 0x0e,
0x33, 0x1c, 0x02, 0x2d, 0x3e, 0x11, 0x0f, 0x20, 0x29, 0x06, 0x18, 0x37, 0x24, 0x0b, 0x15, 0x3a,
0x0e, 0x21, 0x3f, 0x10, 0x03, 0x2c, 0x32, 0x1d, 0x14, 0x3b, 0x25, 0x0a, 0x19, 0x36, 0x28, 0x07,
0x3a, 0x15, 0x0b, 0x24, 0x37, 0x18, 0x06, 0x29, 0x20, 0x0f, 0x11, 0x3e, 0x2d, 0x02, 0x1c, 0x33,
0x09, 0x26, 0x38, 0x17, 0x04, 0x2b, 0x35, 0x1a, 0x13, 0x3c, 0x22, 0x0d, 0x1e, 0x31, 0x2f, 0x00,
0x3d, 0x12, 0x0c, 0x23, 0x30, 0x1f, 0x01, 0x2e, 0x27, 0x08, 0x16, 0x39, 0x2a, 0x05, 0x1b, 0x34,
0x1c, 0x33, 0x2d, 0x02, 0x11, 0x3e, 0x20, 0x0f, 0x06, 0x29, 0x37, 0x18, 0x0b, 0x24, 0x3a, 0x15,
0x28, 0x07, 0x19, 0x36, 0x25, 0x0a, 0x14, 0x3b, 0x32, 0x1d, 0x03, 0x2c, 0x3f, 0x10, 0x0e, 0x21,
0x1b, 0x34, 0x2a, 0x05, 0x16, 0x39, 0x27, 0x08, 0x01, 0x2e, 0x30, 0x1f, 0x0c, 0x23, 0x3d, 0x12,
0x2f, 0x00, 0x1e, 0x31, 0x22, 0x0d, 0x13, 0x3c, 0x35, 0x1a, 0x04, 0x2b, 0x38, 0x17, 0x09, 0x26,
0x12, 0x3d, 0x23, 0x0c, 0x1f, 0x30, 0x2e, 0x01, 0x08, 0x27, 0x39, 0x16, 0x05, 0x2a, 0x34, 0x1b,
0x26, 0x09, 0x17, 0x38, 0x2b, 0x04, 0x1a, 0x35, 0x3c, 0x13, 0x0d, 0x22, 0x31, 0x1e, 0x00, 0x2f,
0x15, 0x3a, 0x24, 0x0b, 0x18, 0x37, 0x29, 0x06, 0x0f, 0x20, 0x3e, 0x11, 0x02, 0x2d, 0x33, 0x1c,
0x21, 0x0e, 0x10, 0x3f, 0x2c, 0x03, 0x1d, 0x32, 0x3b, 0x14, 0x0a, 0x25, 0x36, 0x19, 0x07, 0x28
};
/**
* CRC6 is used by 3GPP (TS 25.415, TS 25.446) for header CRCs
* Poly: D^6 + D^5 + D^3 + D^2 + D^1 + 1
*
* TS 25.415 docs: https://www.etsi.org/deliver/etsi_ts/125400_125499/125415/04.06.00_60/ts_125415v040600p.pdf
* TS 25.446 docs: https://www.etsi.org/deliver/etsi_ts/125400_125499/125446/10.01.00_60/ts_125446v100100p.pdf
*/
guint16 crc6_0X6F(guint16 crc, const guint8 *data, int data_len)
{
guint8 tbl_idx;
while (data_len--) {
tbl_idx = (crc << 2) ^ *data;
crc = crc6_table[tbl_idx] & 0x3f;
data++;
}
return crc & 0x3f;
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/