304 lines
7.8 KiB
C
304 lines
7.8 KiB
C
/*
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* OsmocomBB <-> SDR connection bridge
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* TDMA scheduler: handlers for DL / UL bursts on logical channels
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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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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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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 <stdint.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/gsm/protocol/gsm_04_08.h>
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#include <osmocom/gsm/gsm_utils.h>
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#include <osmocom/coding/gsm0503_coding.h>
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#include <osmocom/codec/codec.h>
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#include "l1ctl_proto.h"
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#include "scheduler.h"
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#include "sched_trx.h"
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#include "logging.h"
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#include "trx_if.h"
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#include "l1ctl.h"
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int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
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struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
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const sbit_t *bits, const struct trx_meas_set *meas)
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{
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const struct trx_lchan_desc *lchan_desc;
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int n_errors = -1, n_bits_total, rc;
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sbit_t *buffer, *offset;
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uint8_t l2[128], *mask;
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size_t l2_len;
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/* Set up pointers */
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lchan_desc = &trx_lchan_desc[lchan->type];
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mask = &lchan->rx_burst_mask;
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buffer = lchan->rx_bursts;
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LOGP(DSCHD, LOGL_DEBUG, "Traffic received on %s: fn=%u ts=%u bid=%u\n",
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lchan_desc->name, fn, ts->index, bid);
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/* Align to the first burst of a block */
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if (*mask == 0x00 && bid != 0)
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return 0;
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/* Update mask */
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*mask |= (1 << bid);
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/* Store the measurements */
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sched_trx_meas_push(lchan, meas);
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/* Copy burst to end of buffer of 8 bursts */
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offset = buffer + bid * 116 + 464;
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memcpy(offset, bits + 3, 58);
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memcpy(offset + 58, bits + 87, 58);
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/* Wait until complete set of bursts */
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if (bid != 3)
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return 0;
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/* Calculate AVG of the measurements */
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sched_trx_meas_avg(lchan, 8);
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/* Check for complete set of bursts */
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if ((*mask & 0xff) != 0xff) {
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LOGP(DSCHD, LOGL_ERROR, "Received incomplete (%s) traffic frame at "
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"fn=%u (%u/%u) for %s\n",
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burst_mask2str(mask, 8), lchan->meas_avg.fn,
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lchan->meas_avg.fn % ts->mf_layout->period,
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ts->mf_layout->period,
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lchan_desc->name);
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/* NOTE: do not abort here, give it a try. Maybe we're lucky ;) */
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}
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/* Keep the mask updated */
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*mask = *mask << 4;
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switch (lchan->tch_mode) {
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case GSM48_CMODE_SIGN:
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case GSM48_CMODE_SPEECH_V1: /* FR */
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rc = gsm0503_tch_fr_decode(l2, buffer,
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1, 0, &n_errors, &n_bits_total);
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break;
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case GSM48_CMODE_SPEECH_EFR: /* EFR */
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rc = gsm0503_tch_fr_decode(l2, buffer,
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1, 1, &n_errors, &n_bits_total);
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break;
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case GSM48_CMODE_SPEECH_AMR: /* AMR */
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/**
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* TODO: AMR requires a dedicated loop,
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* which will be implemented later...
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*/
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LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet\n");
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return -ENOTSUP;
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default:
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LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u\n", lchan->tch_mode);
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return -EINVAL;
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}
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/* Shift buffer by 4 bursts for interleaving */
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memcpy(buffer, buffer + 464, 464);
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/* Check decoding result */
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if (rc < 4) {
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LOGP(DSCHD, LOGL_ERROR, "Received bad TCH frame ending at "
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"fn=%u for %s\n", fn, lchan_desc->name);
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/* Send BFI */
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goto bfi;
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} else if (rc == GSM_MACBLOCK_LEN) {
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/* FACCH received, forward it to the higher layers */
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sched_send_dt_ind(trx, ts, lchan, l2, GSM_MACBLOCK_LEN,
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n_errors, false, false);
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/* Send BFI substituting a stolen TCH frame */
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n_errors = -1; /* ensure fake measurements */
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goto bfi;
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} else {
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/* A good TCH frame received */
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l2_len = rc;
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}
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/* Send a traffic frame to the higher layers */
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return sched_send_dt_ind(trx, ts, lchan, l2, l2_len,
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n_errors, false, true);
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bfi:
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/* Didn't try to decode, fake measurements */
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if (n_errors < 0) {
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lchan->meas_avg = (struct trx_meas_set) {
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.fn = lchan->meas_avg.fn,
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.toa256 = 0,
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.rssi = -110,
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};
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/* No bursts => no errors */
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n_errors = 0;
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}
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/* BFI is not applicable in signalling mode */
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if (lchan->tch_mode == GSM48_CMODE_SIGN)
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return sched_send_dt_ind(trx, ts, lchan, NULL, 0,
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n_errors, true, false);
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/* Bad frame indication */
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l2_len = sched_bad_frame_ind(l2, lchan);
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/* Send a BFI frame to the higher layers */
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return sched_send_dt_ind(trx, ts, lchan, l2, l2_len,
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n_errors, true, true);
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}
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int tx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
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struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid)
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{
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const struct trx_lchan_desc *lchan_desc;
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ubit_t burst[GSM_BURST_LEN];
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ubit_t *buffer, *offset;
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const uint8_t *tsc;
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uint8_t *mask;
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size_t l2_len;
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int rc;
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/* Set up pointers */
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lchan_desc = &trx_lchan_desc[lchan->type];
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mask = &lchan->tx_burst_mask;
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buffer = lchan->tx_bursts;
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/* If we have encoded bursts */
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if (*mask)
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goto send_burst;
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/* Wait until a first burst in period */
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if (bid > 0)
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return 0;
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/* Check the current TCH mode */
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switch (lchan->tch_mode) {
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case GSM48_CMODE_SIGN:
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case GSM48_CMODE_SPEECH_V1: /* FR */
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l2_len = GSM_FR_BYTES;
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break;
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case GSM48_CMODE_SPEECH_EFR: /* EFR */
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l2_len = GSM_EFR_BYTES;
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break;
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case GSM48_CMODE_SPEECH_AMR: /* AMR */
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/**
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* TODO: AMR requires a dedicated loop,
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* which will be implemented later...
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*/
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LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet, "
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"dropping frame...\n");
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/* Forget this primitive */
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sched_prim_drop(lchan);
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return -ENOTSUP;
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default:
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LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u, "
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"dropping frame...\n", lchan->tch_mode);
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/* Forget this primitive */
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sched_prim_drop(lchan);
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return -EINVAL;
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}
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/* Determine and check the payload length */
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if (lchan->prim->payload_len == GSM_MACBLOCK_LEN) {
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l2_len = GSM_MACBLOCK_LEN; /* FACCH */
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} else if (lchan->prim->payload_len != l2_len) {
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LOGP(DSCHD, LOGL_ERROR, "Primitive has odd length %zu "
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"(expected %zu for TCH or %u for FACCH), so dropping...\n",
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lchan->prim->payload_len, l2_len, GSM_MACBLOCK_LEN);
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sched_prim_drop(lchan);
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return -EINVAL;
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}
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/* Shift buffer by 4 bursts back for interleaving */
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memcpy(buffer, buffer + 464, 464);
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/* Encode payload */
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rc = gsm0503_tch_fr_encode(buffer, lchan->prim->payload, l2_len, 1);
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if (rc) {
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LOGP(DSCHD, LOGL_ERROR, "Failed to encode L2 payload (len=%zu): %s\n",
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lchan->prim->payload_len, osmo_hexdump(lchan->prim->payload,
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lchan->prim->payload_len));
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/* Forget this primitive */
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sched_prim_drop(lchan);
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return -EINVAL;
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}
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send_burst:
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/* Determine which burst should be sent */
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offset = buffer + bid * 116;
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/* Update mask */
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*mask |= (1 << bid);
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/* Choose proper TSC */
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tsc = sched_nb_training_bits[trx->tsc];
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/* Compose a new burst */
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memset(burst, 0, 3); /* TB */
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memcpy(burst + 3, offset, 58); /* Payload 1/2 */
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memcpy(burst + 61, tsc, 26); /* TSC */
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memcpy(burst + 87, offset + 58, 58); /* Payload 2/2 */
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memset(burst + 145, 0, 3); /* TB */
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LOGP(DSCHD, LOGL_DEBUG, "Transmitting %s fn=%u ts=%u burst=%u\n",
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lchan_desc->name, fn, ts->index, bid);
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/* Forward burst to scheduler */
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rc = sched_trx_handle_tx_burst(trx, ts, lchan, fn, burst);
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if (rc) {
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/* Forget this primitive */
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sched_prim_drop(lchan);
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/* Reset mask */
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*mask = 0x00;
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return rc;
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}
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/* If we have sent the last (4/4) burst */
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if (*mask == 0x0f) {
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/* Confirm data / traffic sending */
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sched_send_dt_conf(trx, ts, lchan, fn, PRIM_IS_TCH(lchan->prim));
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/* Forget processed primitive */
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sched_prim_drop(lchan);
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/* Reset mask */
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*mask = 0x00;
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}
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return 0;
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}
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