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Introduce LLC layer that has been completely missign so far

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All our MM/CMCE/SNDCP 'decodes' were broken previously, as they
assumed that the MM/CMCE/SNDCP message follows immediately after the
MAC header.  However, there's the LLC layer in between.

This is just simple LLC decoding and does not do re-assembly yet.
This commit is contained in:
Harald Welte 2011-04-24 11:10:52 +02:00
parent 2c6eab8f48
commit b5d6edbb82
4 changed files with 264 additions and 4 deletions
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166
src/tetra_llc_pdu.c Normal file
View file

@ -0,0 +1,166 @@
/* Implementation of some PDU parsing of the TETRA LLC */
/* (C) 2011 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 Affero General Public License as published by
* the Free Software Foundation; either version 3 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/>.
*
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <osmocom/core/utils.h>
#include "tetra_common.h"
#include "tetra_llc_pdu.h"
static const struct value_string tetra_llc_pdut_names[] = {
{ TLLC_PDUT_BL_ADATA, "BL-ADATA" },
{ TLLC_PDUT_BL_DATA, "BL-DATA" },
{ TLLC_PDUT_BL_UDATA, "BL-UDATA" },
{ TLLC_PDUT_BL_ACK, "BL-ACK" },
{ TLLC_PDUT_BL_ADATA_FCS, "BL-ADATA-FCS" },
{ TLLC_PDUT_BL_DATA_FCS, "BL-DATA-FCS" },
{ TLLC_PDUT_BL_UDATA_FCS, "BL-UDATA-FCS" },
{ TLLC_PDUT_BL_ACK_FCS, "BL-ACK-FCS" },
{ TLLC_PDUT_AL_SETUP, "AL-SETUP" },
{ TLLC_PDUT_AL_DATA_FINAL, "AL-DATA/FINAL" },
{ TLLC_PDUT_AL_UDATA_UFINAL, "AL-UDATA/FINAL" },
{ TLLC_PDUT_AL_ACK_RNR, "AL-ACK/AL-RNR" },
{ TLLC_PDUT_AL_RECONNECT, "AL-RECONNECT" },
{ TLLC_PDUT_SUPPL, "AL-SUPPLEMENTARY" },
{ TLLC_PDUT_L2SIG, "AL-L2SIG" },
{ TLLD_PDUT_AL_DISC, "AL-DISC" },
{ 0, NULL }
};
const char *tetra_get_llc_pdut_name(uint8_t pdut)
{
return get_value_string(tetra_llc_pdut_names, pdut);
}
static const struct value_string pdut_dec_names[] = {
{ TLLC_PDUT_DEC_BL_ADATA, "BL-ADATA" },
{ TLLC_PDUT_DEC_BL_DATA, "BL-DATA" },
{ TLLC_PDUT_DEC_BL_UDATA, "BL-UDATA" },
{ TLLC_PDUT_DEC_BL_ACK, "BL-ACK" },
{ TLLC_PDUT_DEC_AL_SETUP, "AL-SETUP" },
{ TLLC_PDUT_DEC_AL_DATA, "AL-DATA" },
{ TLLC_PDUT_DEC_AL_FINAL, "AL-FINAL" },
{ TLLC_PDUT_DEC_AL_UDATA, "AL-UDATA" },
{ TLLC_PDUT_DEC_AL_UFINAL, "AL-UFINAL" },
{ TLLC_PDUT_DEC_AL_ACK, "AL-ACK" },
{ TLLC_PDUT_DEC_AL_RNR, "AL-RNR" },
{ TLLC_PDUT_DEC_AL_RECONNECT, "AL-RECONNECT" },
{ TLLC_PDUT_DEC_AL_DISC, "AL-DISC" },
{ TLLC_PDUT_DEC_ALX_DATA, "ALX-DATA" },
{ TLLC_PDUT_DEC_ALX_FINAL, "ALX-FINAL" },
{ TLLC_PDUT_DEC_ALX_UDATA, "ALX-UDATA" },
{ TLLC_PDUT_DEC_ALX_UFINAL, "ALX-UFINAL" },
{ TLLC_PDUT_DEC_ALX_ACK, "ALX-ACK" },
{ TLLC_PDUT_DEC_ALX_RNR, "ALX-RNR" },
{ 0, NULL }
};
const char *tetra_get_llc_pdut_dec_name(enum tllc_pdut_dec pdut)
{
return get_value_string(pdut_dec_names, pdut);
}
int tetra_llc_pdu_parse(struct tetra_llc_pdu *lpp, uint8_t *buf, int len)
{
uint8_t *cur = buf;
uint8_t pdu_type;
pdu_type = bits_to_uint(cur, 4);
cur += 4;
switch (pdu_type) {
case TLLC_PDUT_BL_ADATA_FCS:
/* FIXME */
len -= 32;
case TLLC_PDUT_BL_ADATA:
lpp->nr = *cur++;
lpp->ns = *cur++;
lpp->tl_sdu = cur;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_BL_ADATA;
break;
case TLLC_PDUT_BL_DATA_FCS:
/* FIXME */
len -= 32;
case TLLC_PDUT_BL_DATA:
lpp->ns = *cur++;
lpp->tl_sdu = cur;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_BL_DATA;
break;
case TLLC_PDUT_BL_UDATA_FCS:
/* FIXME */
len -= 32;
case TLLC_PDUT_BL_UDATA:
lpp->tl_sdu = cur;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_BL_UDATA;
break;
case TLLC_PDUT_AL_DATA_FINAL:
if (*cur++) {
/* FINAL */
cur++;
cur += 2;
lpp->ns = bits_to_uint(cur, 5); cur += 5;
lpp->ss = bits_to_uint(cur, 8); cur += 8;
if (*cur++) {
/* FIXME: FCS */
len -= 32;
}
lpp->tl_sdu = cur;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_AL_FINAL;
} else {
/* DATA Table 21.19 */
cur++;
lpp->ns = bits_to_uint(cur, 3); cur += 3;
lpp->ss = bits_to_uint(cur, 8); cur += 8;
lpp->tl_sdu = cur;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_AL_DATA;
}
break;
case TLLC_PDUT_AL_UDATA_UFINAL:
if (*cur++) {
/* UFINAL 21.2.3.7 / Table 21.26 */
lpp->ns = bits_to_uint(cur, 8); cur+= 8;
lpp->ss = bits_to_uint(cur, 8); cur+= 8;
lpp->tl_sdu = cur;
/* FIXME: FCS */
len -= 32;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_AL_UFINAL;
} else {
/* UDATA 21.2.3.6 / Table 21.24 */
lpp->ns = bits_to_uint(cur, 8); cur+= 8;
lpp->ss = bits_to_uint(cur, 8); cur+= 8;
lpp->tl_sdu = cur;
lpp->tl_sdu_len = len - (cur - buf);
lpp->pdu_type = TLLC_PDUT_DEC_AL_UDATA;
}
break;
}
return (cur - buf);
}