diff options
Diffstat (limited to 'epan/crc8-tvb.c')
| -rw-r--r-- | epan/crc8-tvb.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/epan/crc8-tvb.c b/epan/crc8-tvb.c new file mode 100644 index 00000000..fa994cc0 --- /dev/null +++ b/epan/crc8-tvb.c @@ -0,0 +1,99 @@ +/* crc8.c + * + * Checks the checksum (FCS) of the 3G TS 27.010 Multiplexing protocol. + * The algorithm to check the FCS is described in "3G TS 27.010 V2.0.0 (1999-06)" + * See: www.3gpp.org/ftp/tsg_t/TSG_T/TSGT_04/docs/PDFs/TP-99119.pdf + * or: http://www.3gpp.org/ftp/Specs/html-info/27010.htm + * + * Polynom: (x^8 + x^2 + x^1 + 1) + * + * 2011 Hans-Christoph Schemmel <hans-christoph.schemmel[AT]cinterion.com> + * + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * SPDX-License-Identifier: GPL-2.0-or-later + * +*/ + +#include "config.h" + +#include <glib.h> +#include <epan/tvbuff.h> +#include <epan/crc8-tvb.h> + +/** + * Reversed CRC table + *****************************************************************************/ +static const guint8 crctable[256] = { /*reversed, 8-bit, poly=0x07*/ + 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, + 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, + 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, + 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, + 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, + 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, + 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, + 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, + 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, + 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, + 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, + 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, + 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, + 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, + 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, + 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF +}; + + +gboolean check_fcs(tvbuff_t *p, guint8 len, guint8 offset, guint8 received_fcs){ + /*Init*/ + guint8 FCS = 0xFF; + /*len is the number of bytes in the message, p points to message*/ + while (len--) { + guint8 tmp; + + tmp = FCS^tvb_get_guint8(p,offset); + offset++; + FCS=crctable[tmp]; + } + /*Ones complement*/ + FCS=crctable[FCS^received_fcs]; + /*0xCF is the reversed order of 11110011.*/ + if (FCS==0xCF) { + /*FCS is OK*/ + return TRUE; + } + else { + /*FCS is not OK*/ + return FALSE; + } +} + +guint8 get_crc8_ieee8023_epon(tvbuff_t *p, guint8 len, guint8 offset) { + guint8 FCS = 0x00; + + while (len--) { + guint8 tmp; + + tmp = FCS^tvb_get_guint8(p,offset); + offset++; + FCS=crctable[tmp]; + } + + return FCS; +} + +/* + * Editor modelines - https://www.wireshark.org/tools/modelines.html + * + * Local variables: + * c-basic-offset: 8 + * tab-width: 8 + * indent-tabs-mode: t + * End: + * + * vi: set shiftwidth=8 tabstop=8 noexpandtab: + * :indentSize=8:tabSize=8:noTabs=false: + */ |