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#include "Octetstring.hh"
#include "Error.hh"
#include "Logger.hh"
#include "IuUP_Types.hh"
#include <stdint.h>
extern "C" {
typedef uint8_t ubit_t;
typedef uint8_t pbit_t;
static int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits)
{
unsigned int i;
ubit_t *cur = out;
ubit_t *limit = out + num_bits;
for (i = 0; i < (num_bits/8)+1; i++) {
pbit_t byte = in[i];
*cur++ = (byte >> 7) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 6) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 5) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 4) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 3) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 2) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 1) & 1;
if (cur >= limit)
break;
*cur++ = (byte >> 0) & 1;
if (cur >= limit)
break;
}
return cur - out;
}
struct osmo_crc8gen_code {
int bits; /*!< Actual number of bits of the CRC */
uint8_t poly; /*!< Polynom (normal representation, MSB omitted */
uint8_t init; /*!< Initialization value of the CRC state */
uint8_t remainder; /*!< Remainder of the CRC (final XOR) */
};
static uint8_t
osmo_crc8gen_compute_bits(const struct osmo_crc8gen_code *code,
const ubit_t *in, int len)
{
const uint8_t poly = code->poly;
uint8_t crc = code->init;
int i, n = code->bits-1;
for (i=0; i<len; i++) {
uint8_t bit = in[i] & 1;
crc ^= (bit << n);
if (crc & ((uint8_t)1 << n)) {
crc <<= 1;
crc ^= poly;
} else {
crc <<= 1;
}
crc &= ((uint8_t)1 << code->bits) - 1;
}
crc ^= code->remainder;
return crc;
}
struct osmo_crc16gen_code {
int bits; /*!< Actual number of bits of the CRC */
uint16_t poly; /*!< Polynom (normal representation, MSB omitted */
uint16_t init; /*!< Initialization value of the CRC state */
uint16_t remainder; /*!< Remainder of the CRC (final XOR) */
};
static uint16_t
osmo_crc16gen_compute_bits(const struct osmo_crc16gen_code *code,
const ubit_t *in, int len)
{
const uint16_t poly = code->poly;
uint16_t crc = code->init;
int i, n = code->bits-1;
for (i=0; i<len; i++) {
uint16_t bit = in[i] & 1;
crc ^= (bit << n);
if (crc & ((uint16_t)1 << n)) {
crc <<= 1;
crc ^= poly;
} else {
crc <<= 1;
}
crc &= ((uint16_t)1 << code->bits) - 1;
}
crc ^= code->remainder;
return crc;
}
}
static const struct osmo_crc8gen_code iuup_hdr_crc_code = {
.bits = 6,
.poly = 47,
.init = 0,
.remainder = 0,
};
static const struct osmo_crc16gen_code iuup_data_crc_code = {
.bits = 10,
.poly = 563,
.init = 0,
.remainder = 0,
};
static int iuup_get_payload_offset(const uint8_t *iuup_pdu)
{
uint8_t pdu_type = iuup_pdu[0] >> 4;
switch (pdu_type) {
case 0:
case 14:
return 4;
case 1:
return 3;
default:
return -1;
}
}
int osmo_iuup_compute_payload_crc(const uint8_t *iuup_pdu, unsigned int pdu_len)
{
ubit_t buf[1024*8];
uint8_t pdu_type;
int offset, payload_len_bytes;
if (pdu_len < 1)
return -1;
pdu_type = iuup_pdu[0] >> 4;
/* Type 1 has no CRC */
if (pdu_type == 1)
return 0;
offset = iuup_get_payload_offset(iuup_pdu);
if (offset < 0)
return offset;
if (pdu_len < (unsigned int)offset)
return -1;
payload_len_bytes = pdu_len - offset;
osmo_pbit2ubit(buf, iuup_pdu+offset, payload_len_bytes*8);
return osmo_crc16gen_compute_bits(&iuup_data_crc_code, buf, payload_len_bytes*8);
}
int osmo_iuup_compute_header_crc(const uint8_t *iuup_pdu, unsigned int pdu_len)
{
ubit_t buf[2*8];
if (pdu_len < 2)
return -1;
osmo_pbit2ubit(buf, iuup_pdu, 2*8);
return osmo_crc8gen_compute_bits(&iuup_hdr_crc_code, buf, 2*8);
}
/* IuUP CRC Implementation */
/* (C) 2017 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace IuUP__Types {
INTEGER f__IuUP__compute__crc__payload(OCTETSTRING const &in)
{
int crc_calc;
const unsigned char *data = (const unsigned char *)in;
int len = in.lengthof();
crc_calc = osmo_iuup_compute_payload_crc(data, len);
return INTEGER(crc_calc);
}
INTEGER f__IuUP__compute__crc__header(OCTETSTRING const &in)
{
int crc_calc;
const unsigned char *data = (const unsigned char *)in;
int len = in.lengthof();
crc_calc = osmo_iuup_compute_header_crc(data, len);
return INTEGER(crc_calc);
}
OCTETSTRING f__enc__IuUP__PDU(const IuUP__PDU& pdu)
{
TTCN_Buffer buf;
int crc_hdr, crc_payload;
uint8_t in[2];
pdu.encode(IuUP__PDU_descr_, buf, TTCN_EncDec::CT_RAW);
OCTETSTRING ret_val(buf.get_len(), buf.get_data());
crc_hdr = osmo_iuup_compute_header_crc(buf.get_data(), buf.get_len());
crc_payload = osmo_iuup_compute_payload_crc(buf.get_data(), buf.get_len());
in[0] = (crc_hdr & 0x3f) << 2;
in[0] |= (crc_payload & 0x3ff) >> 8;
in[1] = crc_payload & 0xff;
OCTETSTRING CHECKSUM(2, in);
ret_val = substr(ret_val, 0, 2) + CHECKSUM + substr(ret_val, 4, ret_val.lengthof()-4);
return ret_val;
}
}
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