diff options
Diffstat (limited to 'src/rlc_window_ul.cpp')
| -rw-r--r-- | src/rlc_window_ul.cpp | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/rlc_window_ul.cpp b/src/rlc_window_ul.cpp new file mode 100644 index 00000000..32810d1b --- /dev/null +++ b/src/rlc_window_ul.cpp @@ -0,0 +1,125 @@ +/* RLC Window (UL TBF), 3GPP TS 44.060 + * + * Copyright (C) 2013 by Holger Hans Peter Freyther + * Copyright (C) 2023 sysmocom - s.f.m.c. GmbH <info@sysmocom.de> + * + * 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. + */ + +#include "gprs_debug.h" +#include "rlc_window_ul.h" + +extern "C" { +#include <osmocom/core/utils.h> +#include <osmocom/core/bitvec.h> +#include <osmocom/core/logging.h> +} + +void gprs_rlc_v_n::reset() +{ + for (size_t i = 0; i < ARRAY_SIZE(m_v_n); ++i) + m_v_n[i] = GPRS_RLC_UL_BSN_INVALID; +} + +/* Raise V(R) to highest received sequence number not received. */ +void gprs_rlc_ul_window::raise_v_r(const uint16_t bsn) +{ + uint16_t offset_v_r; + offset_v_r = mod_sns(bsn + 1 - v_r()); + /* Positive offset, so raise. */ + if (offset_v_r < (sns() >> 1)) { + while (offset_v_r--) { + const uint16_t _v_r = v_r(); + const uint16_t bsn_no_longer_in_ws = mod_sns(_v_r - ws()); + LOGP(DRLCMACUL, LOGL_DEBUG, "- Mark BSN %u as INVALID\n", bsn_no_longer_in_ws); + m_v_n.mark_invalid(bsn_no_longer_in_ws); + if (offset_v_r) {/* all except the received block */ + LOGP(DRLCMACUL, LOGL_DEBUG, "- Mark BSN %u as MISSING\n", _v_r); + m_v_n.mark_missing(_v_r); + } + raise_v_r_to(1); + } + LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n", v_r()); + } +} + +/* + * Raise V(Q) if possible. This is looped until there is a gap + * (non received block) or the window is empty. + */ +uint16_t gprs_rlc_ul_window::raise_v_q() +{ + uint16_t count = 0; + + while (v_q() != v_r()) { + if (!m_v_n.is_received(v_q())) + break; + LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising " + "V(Q) to %d\n", v_q(), mod_sns(v_q() + 1)); + raise_v_q(1); + count += 1; + } + + return count; +} + +void gprs_rlc_ul_window::receive_bsn(const uint16_t bsn) +{ + m_v_n.mark_received(bsn); + raise_v_r(bsn); +} + +bool gprs_rlc_ul_window::invalidate_bsn(const uint16_t bsn) +{ + bool was_valid = m_v_n.is_received(bsn); + m_v_n.mark_missing(bsn); + + return was_valid; +} + + +/* Update the receive block bitmap */ +uint16_t gprs_rlc_ul_window::update_egprs_rbb(uint8_t *rbb) +{ + uint16_t i; + uint16_t bsn; + uint16_t bitmask = 0x80; + int8_t pos = 0; + int8_t bit_pos = 0; + for (i = 0, bsn = (v_q()+1); ((bsn < (v_r())) && (i < ws())); i++, + bsn = this->mod_sns(bsn + 1)) { + if (m_v_n.is_received(bsn)) { + rbb[pos] = rbb[pos] | bitmask; + } else { + rbb[pos] = rbb[pos] & (~bitmask); + } + bitmask = bitmask >> 1; + bit_pos++; + bit_pos = bit_pos % 8; + if (bit_pos == 0) { + pos++; + bitmask = 0x80; + } + } + return i; +} + +/* Update the receive block bitmap */ +void gprs_rlc_ul_window::update_rbb(char *rbb) +{ + int i; + for (i=0; i < ws(); i++) { + if (m_v_n.is_received((ssn()-1-i) & mod_sns())) + rbb[ws()-1-i] = 'R'; + else + rbb[ws()-1-i] = 'I'; + } +}
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