/src/wireshark/epan/crc8-tvb.c
Line | Count | Source |
1 | | /* crc8.c |
2 | | * |
3 | | * Checks the checksum (FCS) of the 3G TS 27.010 Multiplexing protocol. |
4 | | * The algorithm to check the FCS is described in "3G TS 27.010 V2.0.0 (1999-06)" |
5 | | * See: www.3gpp.org/ftp/tsg_t/TSG_T/TSGT_04/docs/PDFs/TP-99119.pdf |
6 | | * or: http://www.3gpp.org/ftp/Specs/html-info/27010.htm |
7 | | * |
8 | | * Polynom: (x^8 + x^2 + x^1 + 1) |
9 | | * |
10 | | * 2011 Hans-Christoph Schemmel <hans-christoph.schemmel[AT]cinterion.com> |
11 | | * |
12 | | * |
13 | | * Wireshark - Network traffic analyzer |
14 | | * By Gerald Combs <gerald@wireshark.org> |
15 | | * Copyright 1998 Gerald Combs |
16 | | * |
17 | | * SPDX-License-Identifier: GPL-2.0-or-later |
18 | | * |
19 | | */ |
20 | | |
21 | | #include "config.h" |
22 | | |
23 | | #include <glib.h> |
24 | | #include <epan/tvbuff.h> |
25 | | #include <epan/crc8-tvb.h> |
26 | | |
27 | | /** |
28 | | * Reversed CRC table |
29 | | *****************************************************************************/ |
30 | | static const uint8_t crctable[256] = { /*reversed, 8-bit, poly=0x07*/ |
31 | | 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, |
32 | | 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, |
33 | | 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, |
34 | | 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, |
35 | | 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, |
36 | | 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, |
37 | | 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, |
38 | | 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, |
39 | | 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, |
40 | | 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, |
41 | | 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, |
42 | | 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, |
43 | | 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, |
44 | | 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, |
45 | | 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, |
46 | | 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF |
47 | | }; |
48 | | |
49 | | |
50 | 21 | bool check_fcs(tvbuff_t *p, uint8_t len, uint8_t offset, uint8_t received_fcs){ |
51 | | /*Init*/ |
52 | 21 | uint8_t FCS = 0xFF; |
53 | | /*len is the number of bytes in the message, p points to message*/ |
54 | 625 | while (len--) { |
55 | 604 | uint8_t tmp; |
56 | | |
57 | 604 | tmp = FCS^tvb_get_uint8(p,offset); |
58 | 604 | offset++; |
59 | 604 | FCS=crctable[tmp]; |
60 | 604 | } |
61 | | /*Ones complement*/ |
62 | 21 | FCS=crctable[FCS^received_fcs]; |
63 | | /*0xCF is the reversed order of 11110011.*/ |
64 | 21 | if (FCS==0xCF) { |
65 | | /*FCS is OK*/ |
66 | 0 | return true; |
67 | 0 | } |
68 | 21 | else { |
69 | | /*FCS is not OK*/ |
70 | 21 | return false; |
71 | 21 | } |
72 | 21 | } |
73 | | |
74 | 0 | uint8_t get_crc8_ieee8023_epon(tvbuff_t *p, uint8_t len, uint8_t offset) { |
75 | 0 | uint8_t FCS = 0x00; |
76 | |
|
77 | 0 | while (len--) { |
78 | 0 | uint8_t tmp; |
79 | |
|
80 | 0 | tmp = FCS^tvb_get_uint8(p,offset); |
81 | 0 | offset++; |
82 | 0 | FCS=crctable[tmp]; |
83 | 0 | } |
84 | |
|
85 | 0 | return FCS; |
86 | 0 | } |
87 | | |
88 | | /* |
89 | | * Editor modelines - https://www.wireshark.org/tools/modelines.html |
90 | | * |
91 | | * Local variables: |
92 | | * c-basic-offset: 8 |
93 | | * tab-width: 8 |
94 | | * indent-tabs-mode: t |
95 | | * End: |
96 | | * |
97 | | * vi: set shiftwidth=8 tabstop=8 noexpandtab: |
98 | | * :indentSize=8:tabSize=8:noTabs=false: |
99 | | */ |