GNU Radio's GSM Package
a5.h
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1 /*
2  * Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com>
3  *
4  * All Rights Reserved
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License along
17  * with this program; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19  */
20 
21 #pragma once
22 
23 #include <stdint.h>
24 
25 #include <osmocom/core/defs.h>
26 #include <osmocom/core/bits.h>
27 
28 /*! \defgroup a5 GSM A5 ciphering algorithm
29  * @{
30  * \file a5.h */
31 
32 /*! Converts a frame number into the 22 bit number used in A5/x
33  * \param[in] fn The true framenumber
34  * \return 22 bit word
35  */
36 static inline uint32_t
37 osmo_a5_fn_count(uint32_t fn)
38 {
39  int t1 = fn / (26 * 51);
40  int t2 = fn % 26;
41  int t3 = fn % 51;
42  return (t1 << 11) | (t3 << 5) | t2;
43 }
44 
45  /* Notes:
46  * - key must be 8 or 16 (for a5/4) bytes long (or NULL for A5/0)
47  * - the dl and ul pointer must be either NULL or 114 bits long
48  * - fn is the _real_ GSM frame number.
49  * (converted internally to fn_count)
50  */
51 int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul);
52 void osmo_a5_1(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead");
53 void osmo_a5_2(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead");
54 
55 /*! @} */
OSMO_DEPRECATED
#define OSMO_DEPRECATED(text)
Definition: defs.h:41
osmo_a5_1
void osmo_a5_1(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead")
osmo_a5
int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul)
bits.h
t1
uint8_t t1
Definition: gsm_04_08.h:2
t3
uint8_t t3
Definition: gsm_04_08.h:5
t2
uint8_t t2
Definition: gsm_04_08.h:4
ubit_t
uint8_t ubit_t
Definition: bits.h:24
osmo_a5_2
void osmo_a5_2(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead")
defs.h
osmo_a5_fn_count
static uint32_t osmo_a5_fn_count(uint32_t fn)
Definition: a5.h:37