229 lines
6.5 KiB
C
229 lines
6.5 KiB
C
/*
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* OsmocomBB <-> SDR connection bridge
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* TDMA scheduler: common routines for lchan handlers
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*
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* (C) 2017-2020 by Vadim Yanitskiy <axilirator@gmail.com>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (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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*/
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#include <errno.h>
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#include <string.h>
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#include <talloc.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <arpa/inet.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/core/bits.h>
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#include <osmocom/core/gsmtap_util.h>
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#include <osmocom/core/gsmtap.h>
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#include <osmocom/codec/codec.h>
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#include <osmocom/gsm/protocol/gsm_04_08.h>
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#include <osmocom/gsm/protocol/gsm_08_58.h>
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#include <osmocom/bb/trxcon/l1ctl_proto.h>
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#include <osmocom/bb/trxcon/scheduler.h>
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#include <osmocom/bb/trxcon/sched_trx.h>
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#include <osmocom/bb/trxcon/logging.h>
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#include <osmocom/bb/trxcon/trxcon.h>
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#include <osmocom/bb/trxcon/trx_if.h>
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#include <osmocom/bb/trxcon/l1ctl.h>
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/* GSM 05.02 Chapter 5.2.3 Normal Burst (NB) */
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const uint8_t sched_nb_training_bits[8][26] = {
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{
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0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0,
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0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1,
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},
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{
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0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1,
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1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1,
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},
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{
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0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1,
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0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0,
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},
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{
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0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0,
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1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0,
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},
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{
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0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0,
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1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1,
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},
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{
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0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0,
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0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0,
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},
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{
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1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1,
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0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1,
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},
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{
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1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0,
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0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0,
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},
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};
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/* Get a string representation of the burst buffer's completeness.
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* Examples: " ****.." (incomplete, 4/6 bursts)
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* " ****" (complete, all 4 bursts)
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* "**.***.." (incomplete, 5/8 bursts) */
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const char *burst_mask2str(const uint8_t *mask, int bits)
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{
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/* TODO: CSD is interleaved over 22 bursts, so the mask needs to be extended */
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static char buf[8 + 1];
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char *ptr = buf;
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OSMO_ASSERT(bits <= 8 && bits > 0);
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while (--bits >= 0)
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*(ptr++) = (*mask & (1 << bits)) ? '*' : '.';
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*ptr = '\0';
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return buf;
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}
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int sched_gsmtap_send(enum trx_lchan_type lchan_type, uint32_t fn, uint8_t tn,
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uint16_t band_arfcn, int8_t signal_dbm, uint8_t snr,
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const uint8_t *data, size_t data_len)
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{
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const struct trx_lchan_desc *lchan_desc = &trx_lchan_desc[lchan_type];
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/* GSMTAP logging may not be enabled */
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if (gsmtap == NULL)
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return 0;
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/* Omit frames with unknown channel type */
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if (lchan_desc->gsmtap_chan_type == GSMTAP_CHANNEL_UNKNOWN)
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return 0;
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/* TODO: distinguish GSMTAP_CHANNEL_PCH and GSMTAP_CHANNEL_AGCH */
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return gsmtap_send(gsmtap, band_arfcn, tn, lchan_desc->gsmtap_chan_type,
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lchan_desc->ss_nr, fn, signal_dbm, snr, data, data_len);
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}
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int sched_send_dt_ind(struct trx_instance *trx, struct trx_ts *ts,
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struct trx_lchan_state *lchan, uint8_t *l2, size_t l2_len,
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int bit_error_count, bool dec_failed, bool traffic)
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{
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const struct trx_meas_set *meas = &lchan->meas_avg;
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const struct trx_lchan_desc *lchan_desc;
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struct l1ctl_info_dl dl_hdr;
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/* Set up pointers */
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lchan_desc = &trx_lchan_desc[lchan->type];
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/* Fill in known downlink info */
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dl_hdr.chan_nr = lchan_desc->chan_nr | ts->index;
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dl_hdr.link_id = lchan_desc->link_id;
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dl_hdr.band_arfcn = htons(trx->band_arfcn);
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dl_hdr.num_biterr = bit_error_count;
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/* sched_trx_meas_avg() gives us TDMA frame number of the first burst */
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dl_hdr.frame_nr = htonl(meas->fn);
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/* RX level: 0 .. 63 in typical GSM notation (dBm + 110) */
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dl_hdr.rx_level = dbm2rxlev(meas->rssi);
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/* FIXME: set proper values */
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dl_hdr.snr = 0;
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/* Mark frame as broken if so */
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dl_hdr.fire_crc = dec_failed ? 2 : 0;
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/* Put a packet to higher layers */
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l1ctl_tx_dt_ind(trx->l1l, &dl_hdr, l2, l2_len, traffic);
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/* Optional GSMTAP logging */
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if (l2_len > 0 && (!traffic || lchan_desc->chan_nr == RSL_CHAN_OSMO_PDCH)) {
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sched_gsmtap_send(lchan->type, meas->fn, ts->index,
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trx->band_arfcn, meas->rssi, 0, l2, l2_len);
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}
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return 0;
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}
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int sched_send_dt_conf(struct trx_instance *trx, struct trx_ts *ts,
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struct trx_lchan_state *lchan, uint32_t fn, bool traffic)
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{
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const struct trx_lchan_desc *lchan_desc;
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struct l1ctl_info_dl dl_hdr;
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/* Set up pointers */
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lchan_desc = &trx_lchan_desc[lchan->type];
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/* Zero-initialize DL header, because we don't set all fields */
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memset(&dl_hdr, 0x00, sizeof(struct l1ctl_info_dl));
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/* Fill in known downlink info */
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dl_hdr.chan_nr = lchan_desc->chan_nr | ts->index;
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dl_hdr.link_id = lchan_desc->link_id;
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dl_hdr.band_arfcn = htons(trx->band_arfcn);
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dl_hdr.frame_nr = htonl(fn);
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l1ctl_tx_dt_conf(trx->l1l, &dl_hdr, traffic);
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/* Optional GSMTAP logging */
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if (!traffic || lchan_desc->chan_nr == RSL_CHAN_OSMO_PDCH) {
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sched_gsmtap_send(lchan->type, fn, ts->index,
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trx->band_arfcn | ARFCN_UPLINK,
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0, 0, lchan->prim->payload,
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lchan->prim->payload_len);
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}
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return 0;
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}
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/**
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* Composes a bad frame indication message
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* according to the current tch_mode.
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*
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* @param l2 Caller-allocated byte array
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* @param lchan Logical channel to generate BFI for
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* @return How much bytes were written
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*/
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size_t sched_bad_frame_ind(uint8_t *l2, struct trx_lchan_state *lchan)
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{
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switch (lchan->tch_mode) {
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case GSM48_CMODE_SPEECH_V1:
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if (lchan->type == TRXC_TCHF) { /* Full Rate */
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memset(l2, 0x00, GSM_FR_BYTES);
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l2[0] = 0xd0;
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return GSM_FR_BYTES;
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} else { /* Half Rate */
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memset(l2 + 1, 0x00, GSM_HR_BYTES);
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l2[0] = 0x70; /* F = 0, FT = 111 */
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return GSM_HR_BYTES + 1;
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}
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case GSM48_CMODE_SPEECH_EFR: /* Enhanced Full Rate */
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memset(l2, 0x00, GSM_EFR_BYTES);
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l2[0] = 0xc0;
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return GSM_EFR_BYTES;
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case GSM48_CMODE_SPEECH_AMR: /* Adaptive Multi Rate */
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/* FIXME: AMR is not implemented yet */
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return 0;
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case GSM48_CMODE_SIGN:
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LOGP(DSCH, LOGL_ERROR, "BFI is not allowed in signalling mode\n");
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return 0;
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default:
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LOGP(DSCH, LOGL_ERROR, "Invalid TCH mode: %u\n", lchan->tch_mode);
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return 0;
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}
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}
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