libosmogsm  0.9.3
Osmocom GSM library
include/osmocom/gsm/a5.h
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00001 /*
00002  * a5.h
00003  *
00004  * Copyright (C) 2011  Sylvain Munaut <tnt@246tNt.com>
00005  *
00006  * All Rights Reserved
00007  *
00008  * This program is free software; you can redistribute it and/or modify
00009  * it under the terms of the GNU General Public License as published by
00010  * the Free Software Foundation; either version 2 of the License, or
00011  * (at your option) any later version.
00012  *
00013  * This program is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  * GNU General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU General Public License along
00019  * with this program; if not, write to the Free Software Foundation, Inc.,
00020  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00021  */
00022 
00023 #pragma once
00024 
00025 #include <stdint.h>
00026 
00027 #include <osmocom/core/bits.h>
00028 
00041 static inline uint32_t
00042 osmo_a5_fn_count(uint32_t fn)
00043 {
00044         int t1 = fn / (26 * 51);
00045         int t2 = fn % 26;
00046         int t3 = fn % 51;
00047         return (t1 << 11) | (t3 << 5) | t2;
00048 }
00049 
00050         /* Notes:
00051          *  - key must be 8 or 16 (for a5/4) bytes long (or NULL for A5/0)
00052          *  - the dl and ul pointer must be either NULL or 114 bits long
00053          *  - fn is the _real_ GSM frame number.
00054          *    (converted internally to fn_count)
00055          */
00056 int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul);
00057 void osmo_a5_1(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul);
00058 void osmo_a5_2(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul);
00059