118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
/*
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* Copyright (C) 2019 sysmocom - s.f.m.c. GmbH
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* All Rights Reserved
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*
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* SPDX-License-Identifier: AGPL-3.0+
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*
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* Author: Pau Espin Pedrol <pespin@sysmocom.de>
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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 Affero General Public License as published by
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* the Free Software Foundation, either version 3 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 Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* See the COPYING file in the main directory for details.
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*/
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#include "proto_trxd.h"
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#include <osmocom/core/bits.h>
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static void trxd_fill_common(struct trxd_hdr_common *common, const struct trx_ul_burst_ind *bi, uint8_t version)
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{
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common->version = version & 0b1111;
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common->reserved = 0;
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common->tn = bi->tn;
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osmo_store32be(bi->fn, &common->fn);
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}
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static void trxd_fill_v0_specific(struct trxd_hdr_v0_specific *v0, const struct trx_ul_burst_ind *bi)
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{
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int toa_int;
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/* in 1/256 symbols, round to closest integer */
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toa_int = (int) (bi->toa * 256.0 + 0.5);
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v0->rssi = bi->rssi;
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osmo_store16be(toa_int, &v0->toa);
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}
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static void trxd_fill_v1_specific(struct trxd_hdr_v1_specific *v1, const struct trx_ul_burst_ind *bi)
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{
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int16_t ci_int_cB;
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/* deciBels->centiBels, round to closest integer */
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ci_int_cB = (int16_t)((bi->ci * 10) + 0.5);
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v1->idle = !!bi->idle;
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v1->modulation = (bi->modulation == MODULATION_GMSK) ?
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TRXD_MODULATION_GMSK(bi->tss) :
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TRXD_MODULATION_8PSK(bi->tss);
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v1->tsc = bi->tsc;
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osmo_store16be(ci_int_cB, &v1->ci);
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}
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static void trxd_fill_burst_normalized255(uint8_t* soft_bits, const struct trx_ul_burst_ind *bi)
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{
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unsigned i;
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for (i = 0; i < bi->nbits; i++)
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soft_bits[i] = (uint8_t) round(bi->rx_burst[i] * 255.0);
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}
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bool trxd_send_burst_ind_v0(size_t chan, int fd, const struct trx_ul_burst_ind *bi) {
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int rc;
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/* v0 doesn't support idle frames, they are simply dropped, not sent */
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if (bi->idle)
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return true;
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/* +2: Historically (OpenBTS times), two extra non-used bytes are sent appended to each burst */
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char buf[sizeof(struct trxd_hdr_v0) + bi->nbits + 2];
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struct trxd_hdr_v0* pkt = (struct trxd_hdr_v0*)buf;
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trxd_fill_common(&pkt->common, bi, 0);
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trxd_fill_v0_specific(&pkt->v0, bi);
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trxd_fill_burst_normalized255(&pkt->soft_bits[0], bi);
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/* +1: Historical reason. There's an uninitizalied byte in there: pkt->soft_bits[bi->nbits] */
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pkt->soft_bits[bi->nbits + 1] = '\0';
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rc = write(fd, buf, sizeof(struct trxd_hdr_v0) + bi->nbits + 2);
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if (rc <= 0) {
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CLOGCHAN(chan, DMAIN, LOGL_NOTICE, "mDataSockets write(%d) failed: %d\n", fd, rc);
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return false;
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}
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return true;
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}
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bool trxd_send_burst_ind_v1(size_t chan, int fd, const struct trx_ul_burst_ind *bi) {
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int rc;
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size_t buf_len;
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buf_len = sizeof(struct trxd_hdr_v1);
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if (!bi->idle)
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buf_len += bi->nbits;
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char buf[buf_len];
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struct trxd_hdr_v1* pkt = (struct trxd_hdr_v1*)buf;
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trxd_fill_common(&pkt->common, bi, 1);
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trxd_fill_v0_specific(&pkt->v0, bi);
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trxd_fill_v1_specific(&pkt->v1, bi);
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if (!bi->idle)
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trxd_fill_burst_normalized255(&pkt->soft_bits[0], bi);
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rc = write(fd, buf, buf_len);
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if (rc <= 0) {
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CLOGCHAN(chan, DMAIN, LOGL_NOTICE, "mDataSockets write(%d) failed: %d\n", fd, rc);
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return false;
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}
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return true;
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}
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