diff options
Diffstat (limited to 'src/rlc_window_dl.cpp')
| -rw-r--r-- | src/rlc_window_dl.cpp | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/src/rlc_window_dl.cpp b/src/rlc_window_dl.cpp new file mode 100644 index 00000000..41f9887d --- /dev/null +++ b/src/rlc_window_dl.cpp @@ -0,0 +1,182 @@ +/* RLC Window (DL 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 "bts.h" +#include "rlc_window_dl.h" + +extern "C" { +#include <osmocom/core/utils.h> +#include <osmocom/core/bitvec.h> +#include <osmocom/core/logging.h> +} + +static uint16_t bitnum_to_bsn(int bitnum, uint16_t ssn) +{ + return (ssn - 1 - bitnum); +} + +void gprs_rlc_v_b::reset() +{ + for (size_t i = 0; i < ARRAY_SIZE(m_v_b); ++i) + mark_invalid(i); +} + +void gprs_rlc_dl_window::reset() +{ + m_v_s = 0; + m_v_a = 0; + m_v_b.reset(); +} + +int gprs_rlc_dl_window::resend_needed() const +{ + for (uint16_t bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) { + if (m_v_b.is_nacked(bsn) || m_v_b.is_resend(bsn)) + return bsn; + } + + return -1; +} + +int gprs_rlc_dl_window::mark_for_resend() +{ + int resend = 0; + + for (uint16_t bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) { + if (m_v_b.is_unacked(bsn)) { + /* mark to be re-send */ + m_v_b.mark_resend(bsn); + resend += 1; + } + } + + return resend; +} + +int gprs_rlc_dl_window::count_unacked() +{ + uint16_t unacked = 0; + uint16_t bsn; + + for (bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) { + if (!m_v_b.is_acked(bsn)) + unacked += 1; + } + + return unacked; +} + +void gprs_rlc_dl_window::update(struct gprs_rlcmac_bts *bts, const struct bitvec *rbb, + uint16_t first_bsn, uint16_t *lost, + uint16_t *received) +{ + unsigned dist = distance(); + unsigned num_blocks = rbb->cur_bit > dist + ? dist : rbb->cur_bit; + unsigned bsn; + + /* first_bsn is in range V(A)..V(S) */ + + for (unsigned int bitpos = 0; bitpos < num_blocks; bitpos++) { + bool is_ack; + bsn = mod_sns(first_bsn + bitpos); + if (bsn == mod_sns(v_a() - 1)) + break; + + is_ack = bitvec_get_bit_pos(rbb, bitpos) == 1; + + if (is_ack) { + LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn); + if (!m_v_b.is_acked(bsn)) + *received += 1; + m_v_b.mark_acked(bsn); + } else { + LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn); + m_v_b.mark_nacked(bsn); + bts_do_rate_ctr_inc(bts, CTR_RLC_NACKED); + *lost += 1; + } + } +} + +void gprs_rlc_dl_window::update(struct gprs_rlcmac_bts *bts, char *show_rbb, uint16_t ssn, + uint16_t *lost, uint16_t *received) +{ + /* SSN - 1 is in range V(A)..V(S)-1 */ + for (int bitpos = 0; bitpos < ws(); bitpos++) { + uint16_t bsn = mod_sns(bitnum_to_bsn(bitpos, ssn)); + + if (bsn == mod_sns(v_a() - 1)) + break; + + if (show_rbb[ws() - 1 - bitpos] == 'R') { + LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn); + if (!m_v_b.is_acked(bsn)) + *received += 1; + m_v_b.mark_acked(bsn); + } else { + LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn); + m_v_b.mark_nacked(bsn); + bts_do_rate_ctr_inc(bts, CTR_RLC_NACKED); + *lost += 1; + } + } +} + +int gprs_rlc_dl_window::move_window() +{ + int i; + uint16_t bsn; + int moved = 0; + + for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = mod_sns(bsn + 1)) { + if (m_v_b.is_acked(bsn)) { + m_v_b.mark_invalid(bsn); + moved += 1; + } else + break; + } + + return moved; +} + +void gprs_rlc_dl_window::show_state(char *show_v_b) +{ + int i; + uint16_t bsn; + + for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = mod_sns(bsn + 1)) { + uint16_t index = bsn & mod_sns_half(); + switch(m_v_b.get_state(index)) { + case GPRS_RLC_DL_BSN_INVALID: + show_v_b[i] = 'I'; + break; + case GPRS_RLC_DL_BSN_ACKED: + show_v_b[i] = 'A'; + break; + case GPRS_RLC_DL_BSN_RESEND: + show_v_b[i] = 'X'; + break; + case GPRS_RLC_DL_BSN_NACKED: + show_v_b[i] = 'N'; + break; + default: + show_v_b[i] = '?'; + } + } + show_v_b[i] = '\0'; +}
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