Osmocom Packet control Unit (PCU): Network-side GPRS (RLC/MAC); BTS- or BSC-colocated https://osmocom.org/projects/osmopcu
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osmo-pcu/src/csn1.c

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4.1 KiB

/* csn1_enc.c
* Routines for CSN1 dissection in wireshark.
*
* Copyright (C) 2011 Ivan Klyuchnikov
*
* By Vincent Helfre, based on original code by Jari Sassi
* with the gracious authorization of STE
* Copyright (c) 2011 ST-Ericsson
*
* $Id: packet-csn1.c 39140 2011-09-25 22:01:50Z wmeier $
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <assert.h>
#include <string.h>
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include "csn1.h"
#include <gprs_debug.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/utils.h>
const unsigned char ixBitsTab[] = {0, 1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5};
/* Returns no_of_bits (up to 8) masked with 0x2B */
guint8
get_masked_bits8(struct bitvec *vector, unsigned *readIndex, gint bit_offset, const gint no_of_bits)
{
static const guint8 maskBits[] = {0x00, 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x3F, 0x7F, 0xFF};
//gint byte_offset = bit_offset >> 3; /* divide by 8 */
gint relative_bit_offset = bit_offset & 0x07; /* modulo 8 */
guint8 result;
gint bit_shift = 8 - relative_bit_offset - (gint) no_of_bits;
*readIndex -= relative_bit_offset;
if (bit_shift >= 0)
{
result = (0x2B ^ ((guint8)bitvec_read_field(vector, readIndex, 8))) >> bit_shift;
*readIndex-= bit_shift;
result &= maskBits[no_of_bits];
}
else
{
guint8 hight_part = (0x2B ^ ((guint8)bitvec_read_field(vector, readIndex, 8))) & maskBits[8 - relative_bit_offset];
hight_part = (guint8) (hight_part << (-bit_shift));
result = (0x2B ^ ((guint8)bitvec_read_field(vector, readIndex, 8))) >> (8 + bit_shift);
*readIndex = *readIndex - (8 - (-bit_shift));
result |= hight_part;
}
return result;
}
/**
* ================================================================================================
* set initial/start values in help data structure used for packing/unpacking operation
* ================================================================================================
*/
void
csnStreamInit(csnStream_t* ar, gint bit_offset, gint remaining_bits_len)
{
ar->remaining_bits_len = remaining_bits_len;
ar->bit_offset = bit_offset;
ar->direction = 0;
}
static const struct value_string csn1_error_names[] = {
{ CSN_OK, "General 0" },
{ CSN_ERROR_GENERAL, "General -1" },
{ CSN_ERROR_DATA_NOT_VALID, "DATA_NOT VALID" },
{ CSN_ERROR_IN_SCRIPT, "IN SCRIPT" },
{ CSN_ERROR_INVALID_UNION_INDEX, "INVALID UNION INDEX" },
{ CSN_ERROR_NEED_MORE_BITS_TO_UNPACK, "NEED_MORE BITS TO UNPACK" },
{ CSN_ERROR_ILLEGAL_BIT_VALUE, "ILLEGAL BIT VALUE" },
{ CSN_ERROR_INTERNAL, "INTERNAL" },
{ CSN_ERROR_STREAM_NOT_SUPPORTED, "STREAM_NOT_SUPPORTED" },
{ CSN_ERROR_MESSAGE_TOO_LONG, "MESSAGE_TOO_LONG" },
{ 0, NULL }
};
gint16 ProcessError_impl(const char *file, int line, unsigned *readIndex,
const char* sz, gint16 err, const CSN_DESCR* pDescr)
{
/* Don't add trailing newline, top caller is responsible for appending it */
if (err != CSN_OK)
LOGPSRC(DCSN1, LOGL_ERROR, file, line, "%s: error %s (%d) at %s (idx %u)",
sz, get_value_string(csn1_error_names, err), err,
pDescr ? pDescr->sz : "-", *readIndex);
return err;
}