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