|
1
|
/* Copyright 2020 sysmocom s.f.m.c. GmbH
|
|
2
|
* SPDX-License-Identifier: Apache-2.0 */
|
|
3
|
package org.osmocom.IMSIPseudo;
|
|
4
|
|
|
5
|
public class MobileIdentity {
|
|
6
|
public static final byte MI_IMSI = 1;
|
|
7
|
|
|
8
|
/* Convert BCD-encoded digit into printable character
|
|
9
|
* \param[in] bcd A single BCD-encoded digit
|
|
10
|
* \returns single printable character
|
|
11
|
*/
|
|
12
|
public static byte bcd2char(byte bcd)
|
|
13
|
{
|
|
14
|
if (bcd < 0xa)
|
|
15
|
return (byte)('0' + bcd);
|
|
16
|
else
|
|
17
|
return (byte)('A' + (bcd - 0xa));
|
|
18
|
}
|
|
19
|
|
|
20
|
/* Convert BCD to string.
|
|
21
|
* The given nibble offsets are interpreted in BCD order, i.e. nibble 0 is bcd[0] & 0xf, nibble 1 is bcd[0] >> 4, nibble
|
|
22
|
* 3 is bcd[1] & 0xf, etc..
|
|
23
|
* \param[out] dst Output byte array.
|
|
24
|
* \param[in] dst_ofs Where to start writing in dst.
|
|
25
|
* \param[in] dst_len How many bytes are available at dst_ofs.
|
|
26
|
* \param[in] bcd Binary coded data buffer.
|
|
27
|
* \param[in] start_nibble Offset to start from, in nibbles.
|
|
28
|
* \param[in] end_nibble Offset to stop before, in nibbles.
|
|
29
|
* \param[in] allow_hex If false, return false if there are digits other than 0-9.
|
|
30
|
* \returns true on success, false otherwise
|
|
31
|
*/
|
|
32
|
public static boolean bcd2str(byte dst[], byte dst_ofs, byte dst_len,
|
|
33
|
byte bcd[], byte start_nibble, byte end_nibble, boolean allow_hex)
|
|
34
|
{
|
|
35
|
byte nibble_i;
|
|
36
|
byte dst_i = dst_ofs;
|
|
37
|
byte dst_end = (byte)(dst_ofs + dst_len);
|
|
38
|
boolean rc = true;
|
|
39
|
|
|
40
|
for (nibble_i = start_nibble; nibble_i < end_nibble && dst_i < dst_end; nibble_i++, dst_i++) {
|
|
41
|
byte nibble = bcd[(byte)nibble_i >> 1];
|
|
42
|
if ((nibble_i & 1) != 0)
|
|
43
|
nibble >>= 4;
|
|
44
|
nibble &= 0xf;
|
|
45
|
|
|
46
|
if (!allow_hex && nibble > 9)
|
|
47
|
rc = false;
|
|
48
|
|
|
49
|
dst[dst_i] = bcd2char(nibble);
|
|
50
|
}
|
|
51
|
|
|
52
|
return rc;
|
|
53
|
}
|
|
54
|
|
|
55
|
public static byte[] mi2str(byte mi[])
|
|
56
|
{
|
|
57
|
/* The IMSI byte array by example:
|
|
58
|
* 08 99 10 07 00 00 10 74 90
|
|
59
|
*
|
|
60
|
* This is encoded according to 3GPP TS 24.008 10.5.1.4 Mobile
|
|
61
|
* Identity, short the Mobile Identity IEI:
|
|
62
|
*
|
|
63
|
* 08 length for the following MI, in bytes.
|
|
64
|
* 9 = 0b1001
|
|
65
|
* 1 = odd nr of digits
|
|
66
|
* 001 = MI type = IMSI
|
|
67
|
* 9 first IMSI digit (BCD)
|
|
68
|
* 0 second digit
|
|
69
|
* 1 third
|
|
70
|
* ...
|
|
71
|
* 0 14th digit
|
|
72
|
* 9 15th and last digit
|
|
73
|
*
|
|
74
|
* If the IMSI had an even number of digits:
|
|
75
|
*
|
|
76
|
* 08 98 10 07 00 00 10 74 f0
|
|
77
|
*
|
|
78
|
* 08 length for the following MI, in bytes.
|
|
79
|
* 8 = 0b0001
|
|
80
|
* 0 = even nr of digits
|
|
81
|
* 001 = MI type = IMSI
|
|
82
|
* 9 first IMSI digit
|
|
83
|
* 0 second digit
|
|
84
|
* 1 third
|
|
85
|
* ...
|
|
86
|
* 0 14th and last digit
|
|
87
|
* f filler
|
|
88
|
*/
|
|
89
|
byte bytelen = mi[0];
|
|
90
|
byte mi_type = (byte)(mi[1] & 0xf);
|
|
91
|
boolean odd_nr_of_digits = ((mi_type & 0x08) != 0);
|
|
92
|
byte start_nibble = 2 + 1; // 2 to skip the bytelen, 1 to skip the mi_type
|
|
93
|
byte end_nibble = (byte)(2 + bytelen * 2 - (odd_nr_of_digits ? 0 : 1));
|
|
94
|
byte str[] = new byte[end_nibble - start_nibble];
|
|
95
|
bcd2str(str, (byte)0, (byte)str.length, mi, start_nibble, end_nibble, true);
|
|
96
|
return str;
|
|
97
|
}
|
|
98
|
|
|
99
|
public static byte char2bcd(byte c)
|
|
100
|
{
|
|
101
|
if (c >= '0' && c <= '9')
|
|
102
|
return (byte)(c - '0');
|
|
103
|
else if (c >= 'A' && c <= 'F')
|
|
104
|
return (byte)(0xa + (c - 'A'));
|
|
105
|
else if (c >= 'a' && c <= 'f')
|
|
106
|
return (byte)(0xa + (c - 'a'));
|
|
107
|
else
|
|
108
|
return 0;
|
|
109
|
}
|
|
110
|
|
|
111
|
public static byte[] str2mi(byte str[], byte mi_type, byte min_buflen)
|
|
112
|
{
|
|
113
|
boolean odd_digits = ((str.length & 1) != 0);
|
|
114
|
/* 1 nibble of mi_type.
|
|
115
|
* str.length nibbles of MI BCD.
|
|
116
|
*/
|
|
117
|
byte mi_nibbles = (byte)(1 + str.length);
|
|
118
|
byte mi_bytes = (byte)(mi_nibbles / 2 + ((mi_nibbles & 1) != 0? 1 : 0));
|
|
119
|
/* 1 byte of total MI length in bytes, plus the MI nibbles */
|
|
120
|
byte buflen = (byte)(1 + mi_bytes);
|
|
121
|
/* Fill up with 0xff to the requested buffer size */
|
|
122
|
if (buflen < min_buflen)
|
|
123
|
buflen = min_buflen;
|
|
124
|
byte buf[] = new byte[buflen];
|
|
125
|
|
|
126
|
for (byte i = 0; i < buf.length; i++)
|
|
127
|
buf[i] = (byte)0xff;
|
|
128
|
|
|
129
|
/* 1 byte of following MI length in bytes */
|
|
130
|
buf[0] = mi_bytes;
|
|
131
|
|
|
132
|
/* first MI byte: low nibble has the MI type and odd/even indicator bit,
|
|
133
|
* high nibble has the first BCD digit.
|
|
134
|
*/
|
|
135
|
mi_type = (byte)(mi_type & 0x07);
|
|
136
|
if (odd_digits)
|
|
137
|
mi_type |= 0x08;
|
|
138
|
buf[1] = (byte)((char2bcd(str[0]) << 4) + mi_type);
|
|
139
|
|
|
140
|
/* fill in the remaining MI nibbles */
|
|
141
|
byte str_i = 1;
|
|
142
|
for (byte mi_i = 1; mi_i < mi_bytes; mi_i++) {
|
|
143
|
byte data = char2bcd(str[str_i++]);
|
|
144
|
if (str_i < str.length)
|
|
145
|
data |= char2bcd(str[str_i++]) << 4;
|
|
146
|
else
|
|
147
|
data |= 0xf0;
|
|
148
|
buf[1 + mi_i] = data;
|
|
149
|
}
|
|
150
|
return buf;
|
|
151
|
}
|
|
152
|
}
|
