125 lines
3.1 KiB
C++
125 lines
3.1 KiB
C++
/* RLC Window (UL TBF), 3GPP TS 44.060
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*
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* Copyright (C) 2013 by Holger Hans Peter Freyther
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* Copyright (C) 2023 sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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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#include "gprs_debug.h"
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#include "rlc_window_ul.h"
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extern "C" {
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#include <osmocom/core/utils.h>
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#include <osmocom/core/bitvec.h>
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#include <osmocom/core/logging.h>
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}
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void gprs_rlc_v_n::reset()
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{
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for (size_t i = 0; i < ARRAY_SIZE(m_v_n); ++i)
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m_v_n[i] = GPRS_RLC_UL_BSN_INVALID;
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}
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/* Raise V(R) to highest received sequence number not received. */
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void gprs_rlc_ul_window::raise_v_r(const uint16_t bsn)
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{
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uint16_t offset_v_r;
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offset_v_r = mod_sns(bsn + 1 - v_r());
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/* Positive offset, so raise. */
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if (offset_v_r < (sns() >> 1)) {
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while (offset_v_r--) {
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const uint16_t _v_r = v_r();
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const uint16_t bsn_no_longer_in_ws = mod_sns(_v_r - ws());
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LOGP(DRLCMACUL, LOGL_DEBUG, "- Mark BSN %u as INVALID\n", bsn_no_longer_in_ws);
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m_v_n.mark_invalid(bsn_no_longer_in_ws);
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if (offset_v_r) {/* all except the received block */
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LOGP(DRLCMACUL, LOGL_DEBUG, "- Mark BSN %u as MISSING\n", _v_r);
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m_v_n.mark_missing(_v_r);
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}
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raise_v_r_to(1);
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}
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LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n", v_r());
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}
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}
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/*
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* Raise V(Q) if possible. This is looped until there is a gap
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* (non received block) or the window is empty.
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*/
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uint16_t gprs_rlc_ul_window::raise_v_q()
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{
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uint16_t count = 0;
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while (v_q() != v_r()) {
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if (!m_v_n.is_received(v_q()))
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break;
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LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising "
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"V(Q) to %d\n", v_q(), mod_sns(v_q() + 1));
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raise_v_q(1);
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count += 1;
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}
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return count;
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}
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void gprs_rlc_ul_window::receive_bsn(const uint16_t bsn)
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{
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m_v_n.mark_received(bsn);
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raise_v_r(bsn);
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}
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bool gprs_rlc_ul_window::invalidate_bsn(const uint16_t bsn)
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{
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bool was_valid = m_v_n.is_received(bsn);
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m_v_n.mark_missing(bsn);
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return was_valid;
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}
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/* Update the receive block bitmap */
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uint16_t gprs_rlc_ul_window::update_egprs_rbb(uint8_t *rbb)
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{
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uint16_t i;
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uint16_t bsn;
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uint16_t bitmask = 0x80;
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int8_t pos = 0;
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int8_t bit_pos = 0;
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for (i = 0, bsn = (v_q()+1); ((bsn < (v_r())) && (i < ws())); i++,
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bsn = this->mod_sns(bsn + 1)) {
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if (m_v_n.is_received(bsn)) {
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rbb[pos] = rbb[pos] | bitmask;
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} else {
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rbb[pos] = rbb[pos] & (~bitmask);
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}
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bitmask = bitmask >> 1;
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bit_pos++;
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bit_pos = bit_pos % 8;
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if (bit_pos == 0) {
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pos++;
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bitmask = 0x80;
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}
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}
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return i;
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}
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/* Update the receive block bitmap */
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void gprs_rlc_ul_window::update_rbb(char *rbb)
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{
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int i;
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for (i=0; i < ws(); i++) {
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if (m_v_n.is_received((ssn()-1-i) & mod_sns()))
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rbb[ws()-1-i] = 'R';
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else
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rbb[ws()-1-i] = 'I';
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}
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} |