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/*
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: common routines for lchan handlers
*
* (C) 2017 by Vadim Yanitskiy <axilirator@gmail.com>
*
* 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 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <errno.h>
#include <string.h>
#include <talloc.h>
#include <stdint.h>
#include <stdbool.h>
#include <arpa/inet.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/bits.h>
#include <osmocom/codec/codec.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include "l1ctl_proto.h"
#include "scheduler.h"
#include "sched_trx.h"
#include "logging.h"
#include "trx_if.h"
#include "l1ctl.h"
/* GSM 05.02 Chapter 5.2.3 Normal Burst (NB) */
const uint8_t sched_nb_training_bits[8][26] = {
{
0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0,
0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1,
},
{
0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1,
1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1,
},
{
0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1,
0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0,
},
{
0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0,
},
{
0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0,
1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1,
},
{
0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0,
0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0,
},
{
1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1,
0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1,
},
{
1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0,
0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0,
},
};
int sched_send_dt_ind(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint8_t *l2, size_t l2_len,
int bit_error_count, bool dec_failed, bool traffic)
{
const struct trx_lchan_desc *lchan_desc;
struct l1ctl_info_dl dl_hdr;
int dbm_avg;
/* Set up pointers */
lchan_desc = &trx_lchan_desc[lchan->type];
/* Fill in known downlink info */
dl_hdr.chan_nr = lchan_desc->chan_nr | ts->index;
dl_hdr.link_id = lchan_desc->link_id;
dl_hdr.band_arfcn = htons(trx->band_arfcn);
dl_hdr.frame_nr = htonl(lchan->rx_first_fn);
dl_hdr.num_biterr = bit_error_count;
/* Convert average RSSI to RX level */
if (lchan->meas.rssi_num) {
/* RX level: 0 .. 63 in typical GSM notation (dBm + 110) */
dbm_avg = lchan->meas.rssi_sum / lchan->meas.rssi_num;
dl_hdr.rx_level = dbm2rxlev(dbm_avg);
} else {
/* No measurements, assuming the worst */
dl_hdr.rx_level = 0;
}
/* FIXME: set proper values */
dl_hdr.snr = 0;
/* Mark frame as broken if so */
dl_hdr.fire_crc = dec_failed ? 2 : 0;
/* Put a packet to higher layers */
l1ctl_tx_dt_ind(trx->l1l, &dl_hdr, l2, l2_len, traffic);
return 0;
}
int sched_send_dt_conf(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, bool traffic)
{
const struct trx_lchan_desc *lchan_desc;
struct l1ctl_info_dl dl_hdr;
/* Set up pointers */
lchan_desc = &trx_lchan_desc[lchan->type];
/* Zero-initialize DL header, because we don't set all fields */
memset(&dl_hdr, 0x00, sizeof(struct l1ctl_info_dl));
/* Fill in known downlink info */
dl_hdr.chan_nr = lchan_desc->chan_nr | ts->index;
dl_hdr.link_id = lchan_desc->link_id;
dl_hdr.band_arfcn = htons(trx->band_arfcn);
dl_hdr.frame_nr = htonl(fn);
l1ctl_tx_dt_conf(trx->l1l, &dl_hdr, traffic);
return 0;
}
/**
* Composes a bad frame indication message
* according to the current tch_mode.
*
* @param l2 Caller-allocated byte array
* @param lchan Logical channel to generate BFI for
* @return How much bytes were written
*/
size_t sched_bad_frame_ind(uint8_t *l2, struct trx_lchan_state *lchan)
{
switch (lchan->tch_mode) {
case GSM48_CMODE_SPEECH_V1:
if (lchan->type == TRXC_TCHF) { /* Full Rate */
memset(l2, 0x00, GSM_FR_BYTES);
l2[0] = 0xd0;
return GSM_FR_BYTES;
} else { /* Half Rate */
memset(l2 + 1, 0x00, GSM_HR_BYTES);
l2[0] = 0x70; /* F = 0, FT = 111 */
return GSM_HR_BYTES + 1;
}
case GSM48_CMODE_SPEECH_EFR: /* Enhanced Full Rate */
memset(l2, 0x00, GSM_EFR_BYTES);
l2[0] = 0xc0;
return GSM_EFR_BYTES;
case GSM48_CMODE_SPEECH_AMR: /* Adaptive Multi Rate */
/* FIXME: AMR is not implemented yet */
return 0;
case GSM48_CMODE_SIGN:
LOGP(DSCH, LOGL_ERROR, "BFI is not allowed in signalling mode\n");
return 0;
default:
LOGP(DSCH, LOGL_ERROR, "Invalid TCH mode: %u\n", lchan->tch_mode);
return 0;
}
}
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