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srsRAN_4G/lib/src/upper/rlc_um_lte.cc

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/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE 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 Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include "srslte/upper/rlc_um_lte.h"
#include <sstream>
#define RX_MOD_BASE(x) (((x)-vr_uh - cfg.um.rx_window_size) % cfg.um.rx_mod)
namespace srslte {
rlc_um_lte::rlc_um_lte(srslte::log_ref log_,
uint32_t lcid_,
srsue::pdcp_interface_rlc* pdcp_,
srsue::rrc_interface_rlc* rrc_,
srslte::timer_handler* timers_) :
rlc_um_base(log_, lcid_, pdcp_, rrc_, timers_)
{
}
// Warning: must call stop() to properly deallocate all buffers
rlc_um_lte::~rlc_um_lte()
{
stop();
}
bool rlc_um_lte::configure(const rlc_config_t& cnfg_)
{
// determine bearer name and configure Rx/Tx objects
rb_name = get_rb_name(rrc, lcid, cnfg_.um.is_mrb);
// store config
cfg = cnfg_;
rx.reset(new rlc_um_lte_rx(this));
if (not rx->configure()) {
return false;
}
tx.reset(new rlc_um_lte_tx(this));
if (not tx->configure(cfg, rb_name)) {
return false;
}
log->info("%s configured in %s: t_reordering=%d ms, rx_sn_field_length=%u bits, tx_sn_field_length=%u bits\n",
rb_name.c_str(),
srslte::to_string(cnfg_.rlc_mode).c_str(),
cfg.um.t_reordering,
srslte::to_number(cfg.um.rx_sn_field_length),
srslte::to_number(cfg.um.tx_sn_field_length));
rx_enabled = true;
tx_enabled = true;
return true;
}
/****************************************************************************
* Tx Subclass implementation for LTE
***************************************************************************/
rlc_um_lte::rlc_um_lte_tx::rlc_um_lte_tx(rlc_um_base* parent_) : rlc_um_base_tx(parent_) {}
uint32_t rlc_um_lte::rlc_um_lte_tx::get_buffer_state()
{
std::lock_guard<std::mutex> lock(mutex);
// Bytes needed for tx SDUs
uint32_t n_sdus = tx_sdu_queue.size();
uint32_t n_bytes = tx_sdu_queue.size_bytes();
if (tx_sdu) {
n_sdus++;
n_bytes += tx_sdu->N_bytes;
}
// Room needed for header extensions? (integer rounding)
if (n_sdus > 1) {
n_bytes += ((n_sdus - 1) * 1.5) + 0.5;
}
// Room needed for fixed header?
if (n_bytes > 0)
n_bytes += (cfg.um.is_mrb) ? 2 : 3;
return n_bytes;
}
bool rlc_um_lte::rlc_um_lte_tx::configure(const rlc_config_t& cnfg_, std::string rb_name_)
{
cfg = cnfg_;
if (cfg.um.tx_mod == 0) {
log->error("Error configuring %s RLC UM: tx_mod==0\n", rb_name.c_str());
return false;
}
tx_sdu_queue.resize(cnfg_.tx_queue_length);
rb_name = rb_name_;
return true;
}
int rlc_um_lte::rlc_um_lte_tx::build_data_pdu(unique_byte_buffer_t pdu, uint8_t* payload, uint32_t nof_bytes)
{
std::lock_guard<std::mutex> lock(mutex);
rlc_umd_pdu_header_t header;
header.fi = RLC_FI_FIELD_START_AND_END_ALIGNED;
header.sn = vt_us;
header.N_li = 0;
header.sn_size = cfg.um.tx_sn_field_length;
uint32_t to_move = 0;
uint32_t last_li = 0;
uint8_t* pdu_ptr = pdu->msg;
int head_len = rlc_um_packed_length(&header);
int pdu_space = SRSLTE_MIN(nof_bytes, pdu->get_tailroom());
if (pdu_space <= head_len + 1) {
log->warning("%s Cannot build a PDU - %d bytes available, %d bytes required for header\n",
rb_name.c_str(),
nof_bytes,
head_len);
return 0;
}
// Check for SDU segment
if (tx_sdu) {
uint32_t space = pdu_space - head_len;
to_move = space >= tx_sdu->N_bytes ? tx_sdu->N_bytes : space;
log->debug(
"%s adding remainder of SDU segment - %d bytes of %d remaining\n", rb_name.c_str(), to_move, tx_sdu->N_bytes);
memcpy(pdu_ptr, tx_sdu->msg, to_move);
last_li = to_move;
pdu_ptr += to_move;
pdu->N_bytes += to_move;
tx_sdu->N_bytes -= to_move;
tx_sdu->msg += to_move;
if (tx_sdu->N_bytes == 0) {
log->debug(
"%s Complete SDU scheduled for tx. Stack latency: %ld us\n", rb_name.c_str(), tx_sdu->get_latency_us());
tx_sdu.reset();
}
pdu_space -= SRSLTE_MIN(to_move, pdu->get_tailroom());
header.fi |= RLC_FI_FIELD_NOT_START_ALIGNED; // First byte does not correspond to first byte of SDU
}
// Pull SDUs from queue
while (pdu_space > head_len + 1 && tx_sdu_queue.size() > 0) {
log->debug("pdu_space=%d, head_len=%d\n", pdu_space, head_len);
if (last_li > 0) {
header.li[header.N_li++] = last_li;
}
head_len = rlc_um_packed_length(&header);
uint32_t space = pdu_space - head_len;
if (space == 0) {
// we cannot even fit a single byte of the newly added SDU, remove it again
header.N_li--;
break;
}
tx_sdu = tx_sdu_queue.read();
to_move = (space >= tx_sdu->N_bytes) ? tx_sdu->N_bytes : space;
log->debug("%s adding new SDU segment - %d bytes of %d remaining\n", rb_name.c_str(), to_move, tx_sdu->N_bytes);
memcpy(pdu_ptr, tx_sdu->msg, to_move);
last_li = to_move;
pdu_ptr += to_move;
pdu->N_bytes += to_move;
tx_sdu->N_bytes -= to_move;
tx_sdu->msg += to_move;
if (tx_sdu->N_bytes == 0) {
log->debug(
"%s Complete SDU scheduled for tx. Stack latency: %ld us\n", rb_name.c_str(), tx_sdu->get_latency_us());
tx_sdu.reset();
}
pdu_space -= to_move;
}
if (tx_sdu) {
header.fi |= RLC_FI_FIELD_NOT_END_ALIGNED; // Last byte does not correspond to last byte of SDU
}
// Set SN
header.sn = vt_us;
vt_us = (vt_us + 1) % cfg.um.tx_mod;
// Add header and TX
rlc_um_write_data_pdu_header(&header, pdu.get());
memcpy(payload, pdu->msg, pdu->N_bytes);
log->info_hex(payload, pdu->N_bytes, "%s Tx PDU SN=%d (%d B)\n", rb_name.c_str(), header.sn, pdu->N_bytes);
debug_state();
return pdu->N_bytes;
}
void rlc_um_lte::rlc_um_lte_tx::debug_state()
{
log->debug("%s vt_us = %d\n", rb_name.c_str(), vt_us);
}
/****************************************************************************
* Rx subclass implementation
***************************************************************************/
rlc_um_lte::rlc_um_lte_rx::rlc_um_lte_rx(rlc_um_base* parent_) :
rlc_um_base_rx(parent_),
reordering_timer(timers->get_unique_timer())
{
}
rlc_um_lte::rlc_um_lte_rx::~rlc_um_lte_rx() {}
bool rlc_um_lte::rlc_um_lte_rx::configure()
{
if (cfg.um.rx_mod == 0) {
log->error("Error configuring %s RLC UM: rx_mod==0\n", rb_name.c_str());
return false;
}
// check timer
if (not reordering_timer.is_valid()) {
log->error("Configuring RLC UM RX: timers not configured\n");
return false;
}
// configure timer
if (cfg.um.t_reordering > 0) {
reordering_timer.set(static_cast<uint32_t>(cfg.um.t_reordering), [this](uint32_t tid) { timer_expired(tid); });
}
return true;
}
void rlc_um_lte::rlc_um_lte_rx::reestablish()
{
// try to reassemble any SDUs if possible
if (reordering_timer.is_valid() && reordering_timer.is_running()) {
reordering_timer.stop();
timer_expired(reordering_timer.id());
}
reset();
}
void rlc_um_lte::rlc_um_lte_rx::stop()
{
reset();
reordering_timer.stop();
}
void rlc_um_lte::rlc_um_lte_rx::reset()
{
vr_ur = 0;
vr_ux = 0;
vr_uh = 0;
pdu_lost = false;
rx_sdu.reset();
// Drop all messages in RX window
rx_window.clear();
}
void rlc_um_lte::rlc_um_lte_rx::handle_data_pdu(uint8_t* payload, uint32_t nof_bytes)
{
rlc_umd_pdu_header_t header;
rlc_um_read_data_pdu_header(payload, nof_bytes, cfg.um.rx_sn_field_length, &header);
log->info_hex(payload, nof_bytes, "RX %s Rx data PDU SN: %d (%d B)", rb_name.c_str(), header.sn, nof_bytes);
if (RX_MOD_BASE(header.sn) >= RX_MOD_BASE(vr_uh - cfg.um.rx_window_size) &&
RX_MOD_BASE(header.sn) < RX_MOD_BASE(vr_ur)) {
log->info("%s SN: %d outside rx window [%d:%d] - discarding\n", rb_name.c_str(), header.sn, vr_ur, vr_uh);
return;
}
std::map<uint32_t, rlc_umd_pdu_t>::iterator it = rx_window.find(header.sn);
if (rx_window.end() != it) {
log->info("%s Discarding duplicate SN: %d\n", rb_name.c_str(), header.sn);
return;
}
// Write to rx window
rlc_umd_pdu_t pdu = {};
pdu.buf = allocate_unique_buffer(*pool);
if (!pdu.buf) {
log->error("Discarting packet: no space in buffer pool\n");
return;
}
memcpy(pdu.buf->msg, payload, nof_bytes);
pdu.buf->N_bytes = nof_bytes;
// Strip header from PDU
int header_len = rlc_um_packed_length(&header);
pdu.buf->msg += header_len;
pdu.buf->N_bytes -= header_len;
pdu.header = header;
rx_window[header.sn] = std::move(pdu);
// Update vr_uh
if (!inside_reordering_window(header.sn)) {
vr_uh = (header.sn + 1) % cfg.um.rx_mod;
}
// Reassemble and deliver SDUs, while updating vr_ur
log->debug("Entering Reassemble from received PDU\n");
reassemble_rx_sdus();
log->debug("Finished reassemble from received PDU\n");
// Update reordering variables and timers
if (reordering_timer.is_running()) {
if (RX_MOD_BASE(vr_ux) <= RX_MOD_BASE(vr_ur) || (!inside_reordering_window(vr_ux) && vr_ux != vr_uh)) {
reordering_timer.stop();
}
}
if (!reordering_timer.is_running()) {
if (RX_MOD_BASE(vr_uh) > RX_MOD_BASE(vr_ur)) {
reordering_timer.run();
vr_ux = vr_uh;
}
}
debug_state();
}
// No locking required as only called from within handle_data_pdu and timer_expired which lock
void rlc_um_lte::rlc_um_lte_rx::reassemble_rx_sdus()
{
if (!rx_sdu) {
rx_sdu = allocate_unique_buffer(*pool);
if (!rx_sdu) {
log->error("Fatal Error: Couldn't allocate buffer in rlc_um::reassemble_rx_sdus().\n");
return;
}
}
// First catch up with lower edge of reordering window
while (!inside_reordering_window(vr_ur)) {
log->debug("SN=%d is not inside reordering windows\n", vr_ur);
if (rx_window.end() == rx_window.find(vr_ur)) {
log->debug("SN=%d not in rx_window. Reset received SDU\n", vr_ur);
rx_sdu->clear();
} else {
// Handle any SDU segments
for (uint32_t i = 0; i < rx_window[vr_ur].header.N_li; i++) {
int len = rx_window[vr_ur].header.li[i];
log->debug_hex(rx_window[vr_ur].buf->msg,
len,
"Handling segment %d/%d of length %d B of SN=%d\n",
i + 1,
rx_window[vr_ur].header.N_li,
len,
vr_ur);
// Check if we received a middle or end segment
if (rx_sdu->N_bytes == 0 && i == 0 && !rlc_um_start_aligned(rx_window[vr_ur].header.fi)) {
log->warning("Dropping PDU %d in reassembly due to lost start segment\n", vr_ur);
// Advance data pointers and continue with next segment
rx_window[vr_ur].buf->msg += len;
rx_window[vr_ur].buf->N_bytes -= len;
rx_sdu->clear();
metrics.num_lost_pdus++;
break;
}
memcpy(&rx_sdu->msg[rx_sdu->N_bytes], rx_window[vr_ur].buf->msg, len);
rx_sdu->N_bytes += len;
rx_window[vr_ur].buf->msg += len;
rx_window[vr_ur].buf->N_bytes -= len;
if ((pdu_lost && !rlc_um_start_aligned(rx_window[vr_ur].header.fi)) ||
(vr_ur != ((vr_ur_in_rx_sdu + 1) % cfg.um.rx_mod))) {
log->warning("Dropping remainder of lost PDU (lower edge middle segments, vr_ur=%d, vr_ur_in_rx_sdu=%d)\n",
vr_ur,
vr_ur_in_rx_sdu);
rx_sdu->clear();
metrics.num_lost_pdus++;
} else {
log->info_hex(rx_sdu->msg,
rx_sdu->N_bytes,
"%s Rx SDU vr_ur=%d, i=%d (lower edge middle segments)",
rb_name.c_str(),
vr_ur,
i);
rx_sdu->set_timestamp();
metrics.num_rx_sdus++;
metrics.num_rx_sdu_bytes += rx_sdu->N_bytes;
if (cfg.um.is_mrb) {
pdcp->write_pdu_mch(lcid, std::move(rx_sdu));
} else {
pdcp->write_pdu(lcid, std::move(rx_sdu));
}
rx_sdu = allocate_unique_buffer(*pool);
if (!rx_sdu) {
log->error("Fatal Error: Couldn't allocate buffer in rlc_um::reassemble_rx_sdus().\n");
return;
}
}
pdu_lost = false;
}
// Handle last segment
if (rx_sdu->N_bytes > 0 || rlc_um_start_aligned(rx_window[vr_ur].header.fi)) {
log->info("Writing last segment in SDU buffer. Lower edge vr_ur=%d, Buffer size=%d, segment size=%d\n",
vr_ur,
rx_sdu->N_bytes,
rx_window[vr_ur].buf->N_bytes);
memcpy(&rx_sdu->msg[rx_sdu->N_bytes], rx_window[vr_ur].buf->msg, rx_window[vr_ur].buf->N_bytes);
rx_sdu->N_bytes += rx_window[vr_ur].buf->N_bytes;
vr_ur_in_rx_sdu = vr_ur;
if (rlc_um_end_aligned(rx_window[vr_ur].header.fi)) {
if (pdu_lost && !rlc_um_start_aligned(rx_window[vr_ur].header.fi)) {
log->warning("Dropping remainder of lost PDU (lower edge last segments)\n");
rx_sdu->clear();
metrics.num_lost_pdus++;
} else {
log->info_hex(
rx_sdu->msg, rx_sdu->N_bytes, "%s Rx SDU vr_ur=%d (lower edge last segments)", rb_name.c_str(), vr_ur);
rx_sdu->set_timestamp();
metrics.num_rx_sdus++;
metrics.num_rx_sdu_bytes += rx_sdu->N_bytes;
if (cfg.um.is_mrb) {
pdcp->write_pdu_mch(lcid, std::move(rx_sdu));
} else {
pdcp->write_pdu(lcid, std::move(rx_sdu));
}
rx_sdu = allocate_unique_buffer(*pool);
if (!rx_sdu) {
log->error("Fatal Error: Couldn't allocate buffer in rlc_um::reassemble_rx_sdus().\n");
return;
}
}
pdu_lost = false;
}
}
// Clean up rx_window
rx_window.erase(vr_ur);
}
vr_ur = (vr_ur + 1) % cfg.um.rx_mod;
}
// Now update vr_ur until we reach an SN we haven't yet received
while (rx_window.end() != rx_window.find(vr_ur)) {
log->debug("Reassemble loop for vr_ur=%d\n", vr_ur);
if (not pdu_belongs_to_rx_sdu()) {
log->warning(
"PDU SN=%d lost, stop reassambling SDU (vr_ur_in_rx_sdu=%d)\n", vr_ur_in_rx_sdu + 1, vr_ur_in_rx_sdu);
pdu_lost = false; // Reset flag to not prevent reassembling of further segments
rx_sdu->clear();
}
// Handle any SDU segments
for (uint32_t i = 0; i < rx_window[vr_ur].header.N_li; i++) {
uint16_t len = rx_window[vr_ur].header.li[i];
log->debug("Handling SDU segment i=%d with len=%d of vr_ur=%d N_li=%d [%s]\n",
i,
len,
vr_ur,
rx_window[vr_ur].header.N_li,
rlc_fi_field_text[rx_window[vr_ur].header.fi]);
// Check if the first part of the PDU is a middle or end segment
if (rx_sdu->N_bytes == 0 && i == 0 && !rlc_um_start_aligned(rx_window[vr_ur].header.fi)) {
log->warning_hex(
rx_window[vr_ur].buf->msg, len, "Dropping first %d B of SN %d due to lost start segment\n", len, vr_ur);
if (rx_window[vr_ur].buf->N_bytes < len) {
log->error("Dropping remaining remainder of SN %d too (N_bytes=%u < len=%d)\n",
vr_ur,
rx_window[vr_ur].buf->N_bytes,
len);
goto clean_up_rx_window;
}
// Advance data pointers and continue with next segment
rx_window[vr_ur].buf->msg += len;
rx_window[vr_ur].buf->N_bytes -= len;
rx_sdu->clear();
metrics.num_lost_pdus++;
// Reset flag, it is safe to process all remaining segments of this PDU
pdu_lost = false;
continue;
}
// Check available space in SDU
if ((uint32_t)len > rx_sdu->get_tailroom()) {
log->error("Dropping PDU %d due to buffer mis-alignment (current segment len %d B, received %d B)\n",
vr_ur,
rx_sdu->N_bytes,
len);
rx_sdu->clear();
metrics.num_lost_pdus++;
goto clean_up_rx_window;
}
if (not pdu_belongs_to_rx_sdu()) {
log->info_hex(rx_window[vr_ur].buf->msg, len, "Copying first %d bytes of new SDU\n", len);
log->info("Updating vr_ur_in_rx_sdu. old=%d, new=%d\n", vr_ur_in_rx_sdu, vr_ur);
vr_ur_in_rx_sdu = vr_ur;
} else {
log->info_hex(rx_window[vr_ur].buf->msg,
len,
"Concatenating %d bytes in to current length %d. rx_window remaining bytes=%d, "
"vr_ur_in_rx_sdu=%d, vr_ur=%d, rx_mod=%d, last_mod=%d\n",
len,
rx_sdu->N_bytes,
rx_window[vr_ur].buf->N_bytes,
vr_ur_in_rx_sdu,
vr_ur,
cfg.um.rx_mod,
(vr_ur_in_rx_sdu + 1) % cfg.um.rx_mod);
}
memcpy(&rx_sdu->msg[rx_sdu->N_bytes], rx_window[vr_ur].buf->msg, len);
rx_sdu->N_bytes += len;
rx_window[vr_ur].buf->msg += len;
rx_window[vr_ur].buf->N_bytes -= len;
vr_ur_in_rx_sdu = vr_ur;
if (pdu_belongs_to_rx_sdu()) {
log->info_hex(rx_sdu->msg,
rx_sdu->N_bytes,
"%s Rx SDU vr_ur=%d, i=%d, (update vr_ur middle segments)",
rb_name.c_str(),
vr_ur,
i);
rx_sdu->set_timestamp();
metrics.num_rx_sdus++;
metrics.num_rx_sdu_bytes += rx_sdu->N_bytes;
if (cfg.um.is_mrb) {
pdcp->write_pdu_mch(lcid, std::move(rx_sdu));
} else {
pdcp->write_pdu(lcid, std::move(rx_sdu));
}
rx_sdu = allocate_unique_buffer(*pool);
if (!rx_sdu) {
log->error("Fatal Error: Couldn't allocate buffer in rlc_um::reassemble_rx_sdus().\n");
return;
}
} else {
log->warning("Dropping remainder of lost PDU (update vr_ur middle segments, vr_ur=%d, vr_ur_in_rx_sdu=%d)\n",
vr_ur,
vr_ur_in_rx_sdu);
// Advance data pointers and continue with next segment
rx_window[vr_ur].buf->msg += len;
rx_window[vr_ur].buf->N_bytes -= len;
metrics.num_lost_pdus++;
}
pdu_lost = false;
}
// Handle last segment
if (rx_sdu->N_bytes == 0 && rx_window[vr_ur].header.N_li == 0 &&
!rlc_um_start_aligned(rx_window[vr_ur].header.fi)) {
log->warning("Dropping PDU %d during last segment handling due to lost start segment\n", vr_ur);
rx_sdu->clear();
metrics.num_lost_pdus++;
goto clean_up_rx_window;
}
if (rx_sdu->N_bytes < SRSLTE_MAX_BUFFER_SIZE_BYTES &&
rx_window[vr_ur].buf->N_bytes < SRSLTE_MAX_BUFFER_SIZE_BYTES &&
rx_window[vr_ur].buf->N_bytes + rx_sdu->N_bytes < SRSLTE_MAX_BUFFER_SIZE_BYTES) {
log->info_hex(rx_window[vr_ur].buf->msg,
rx_window[vr_ur].buf->N_bytes,
"Writing last segment in SDU buffer. Updating vr_ur=%d, vr_ur_in_rx_sdu=%d, Buffer size=%d, "
"segment size=%d\n",
vr_ur,
vr_ur_in_rx_sdu,
rx_sdu->N_bytes,
rx_window[vr_ur].buf->N_bytes);
memcpy(&rx_sdu->msg[rx_sdu->N_bytes], rx_window[vr_ur].buf->msg, rx_window[vr_ur].buf->N_bytes);
rx_sdu->N_bytes += rx_window[vr_ur].buf->N_bytes;
} else {
log->error("Out of bounds while reassembling SDU buffer in UM: sdu_len=%d, window_buffer_len=%d, vr_ur=%d\n",
rx_sdu->N_bytes,
rx_window[vr_ur].buf->N_bytes,
vr_ur);
}
vr_ur_in_rx_sdu = vr_ur;
if (rlc_um_end_aligned(rx_window[vr_ur].header.fi)) {
if (pdu_lost && !rlc_um_start_aligned(rx_window[vr_ur].header.fi)) {
log->warning("Dropping remainder of lost PDU (update vr_ur last segments)\n");
rx_sdu->clear();
metrics.num_lost_pdus++;
} else {
log->info_hex(
rx_sdu->msg, rx_sdu->N_bytes, "%s Rx SDU vr_ur=%d (update vr_ur last segments)", rb_name.c_str(), vr_ur);
rx_sdu->set_timestamp();
metrics.num_rx_sdus++;
metrics.num_rx_sdu_bytes += rx_sdu->N_bytes;
if (cfg.um.is_mrb) {
pdcp->write_pdu_mch(lcid, std::move(rx_sdu));
} else {
pdcp->write_pdu(lcid, std::move(rx_sdu));
}
rx_sdu = allocate_unique_buffer(*pool);
if (!rx_sdu) {
log->error("Fatal Error: Couldn't allocate buffer in rlc_um::reassemble_rx_sdus().\n");
return;
}
}
pdu_lost = false;
}
clean_up_rx_window:
// Clean up rx_window
rx_window.erase(vr_ur);
vr_ur = (vr_ur + 1) % cfg.um.rx_mod;
}
}
// Only called when lock is hold
bool rlc_um_lte::rlc_um_lte_rx::pdu_belongs_to_rx_sdu()
{
// return true if the currently received SDU
if (((vr_ur_in_rx_sdu + 1) % cfg.um.rx_mod == vr_ur) || (vr_ur == vr_ur_in_rx_sdu)) {
return true;
}
return false;
}
// Only called when lock is hold
// 36.322 Section 5.1.2.2.1
bool rlc_um_lte::rlc_um_lte_rx::inside_reordering_window(uint16_t sn)
{
if (cfg.um.rx_window_size == 0 || rx_window.empty()) {
return true;
}
if (RX_MOD_BASE(vr_uh - cfg.um.rx_window_size) <= RX_MOD_BASE(sn) && RX_MOD_BASE(sn) < RX_MOD_BASE(vr_uh)) {
return true;
} else {
return false;
}
}
/****************************************************************************
* Timeout callback interface
***************************************************************************/
void rlc_um_lte::rlc_um_lte_rx::timer_expired(uint32_t timeout_id)
{
if (reordering_timer.id() == timeout_id) {
// 36.322 v10 Section 5.1.2.2.4
log->info("%s reordering timeout expiry - updating vr_ur and reassembling\n", rb_name.c_str());
log->warning("Lost PDU SN: %d\n", vr_ur);
pdu_lost = true;
if (rx_sdu != NULL) {
rx_sdu->clear();
}
while (RX_MOD_BASE(vr_ur) < RX_MOD_BASE(vr_ux)) {
vr_ur = (vr_ur + 1) % cfg.um.rx_mod;
log->debug("Entering Reassemble from timeout id=%d\n", timeout_id);
reassemble_rx_sdus();
log->debug("Finished reassemble from timeout id=%d\n", timeout_id);
}
if (RX_MOD_BASE(vr_uh) > RX_MOD_BASE(vr_ur)) {
reordering_timer.run();
vr_ux = vr_uh;
}
debug_state();
}
}
/****************************************************************************
* Helper functions
***************************************************************************/
void rlc_um_lte::rlc_um_lte_rx::debug_state()
{
log->debug("%s vr_ur = %d, vr_ux = %d, vr_uh = %d\n", rb_name.c_str(), vr_ur, vr_ux, vr_uh);
}
/****************************************************************************
* Header pack/unpack helper functions
* Ref: 3GPP TS 36.322 v10.0.0 Section 6.2.1
***************************************************************************/
void rlc_um_read_data_pdu_header(byte_buffer_t* pdu, rlc_umd_sn_size_t sn_size, rlc_umd_pdu_header_t* header)
{
rlc_um_read_data_pdu_header(pdu->msg, pdu->N_bytes, sn_size, header);
}
void rlc_um_read_data_pdu_header(uint8_t* payload,
uint32_t nof_bytes,
rlc_umd_sn_size_t sn_size,
rlc_umd_pdu_header_t* header)
{
uint8_t ext;
uint8_t* ptr = payload;
// Fixed part
if (sn_size == rlc_umd_sn_size_t::size5bits) {
header->fi = (rlc_fi_field_t)((*ptr >> 6) & 0x03); // 2 bits FI
ext = ((*ptr >> 5) & 0x01); // 1 bit EXT
header->sn = *ptr & 0x1F; // 5 bits SN
ptr++;
} else {
header->fi = (rlc_fi_field_t)((*ptr >> 3) & 0x03); // 2 bits FI
ext = ((*ptr >> 2) & 0x01); // 1 bit EXT
header->sn = (*ptr & 0x03) << 8; // 2 bits SN
ptr++;
header->sn |= (*ptr & 0xFF); // 8 bits SN
ptr++;
}
header->sn_size = sn_size;
// Extension part
header->N_li = 0;
while (ext) {
if (header->N_li % 2 == 0) {
ext = ((*ptr >> 7) & 0x01);
header->li[header->N_li] = (*ptr & 0x7F) << 4; // 7 bits of LI
ptr++;
header->li[header->N_li] |= (*ptr & 0xF0) >> 4; // 4 bits of LI
header->N_li++;
} else {
ext = (*ptr >> 3) & 0x01;
header->li[header->N_li] = (*ptr & 0x07) << 8; // 3 bits of LI
ptr++;
header->li[header->N_li] |= (*ptr & 0xFF); // 8 bits of LI
header->N_li++;
ptr++;
}
}
}
void rlc_um_write_data_pdu_header(rlc_umd_pdu_header_t* header, byte_buffer_t* pdu)
{
uint32_t i;
uint8_t ext = (header->N_li > 0) ? 1 : 0;
// Make room for the header
uint32_t len = rlc_um_packed_length(header);
pdu->msg -= len;
uint8_t* ptr = pdu->msg;
// Fixed part
if (header->sn_size == rlc_umd_sn_size_t::size5bits) {
*ptr = (header->fi & 0x03) << 6; // 2 bits FI
*ptr |= (ext & 0x01) << 5; // 1 bit EXT
*ptr |= header->sn & 0x1F; // 5 bits SN
ptr++;
} else {
*ptr = (header->fi & 0x03) << 3; // 3 Reserved bits | 2 bits FI
*ptr |= (ext & 0x01) << 2; // 1 bit EXT
*ptr |= (header->sn & 0x300) >> 8; // 2 bits SN
ptr++;
*ptr = (header->sn & 0xFF); // 8 bits SN
ptr++;
}
// Extension part
i = 0;
while (i < header->N_li) {
ext = ((i + 1) == header->N_li) ? 0 : 1;
*ptr = (ext & 0x01) << 7; // 1 bit header
*ptr |= (header->li[i] & 0x7F0) >> 4; // 7 bits of LI
ptr++;
*ptr = (header->li[i] & 0x00F) << 4; // 4 bits of LI
i++;
if (i < header->N_li) {
ext = ((i + 1) == header->N_li) ? 0 : 1;
*ptr |= (ext & 0x01) << 3; // 1 bit header
*ptr |= (header->li[i] & 0x700) >> 8; // 3 bits of LI
ptr++;
*ptr = (header->li[i] & 0x0FF); // 8 bits of LI
ptr++;
i++;
}
}
// Pad if N_li is odd
if (header->N_li % 2 == 1)
ptr++;
pdu->N_bytes += ptr - pdu->msg;
}
uint32_t rlc_um_packed_length(rlc_umd_pdu_header_t* header)
{
uint32_t len = 0;
if (header->sn_size == rlc_umd_sn_size_t::size5bits) {
len += 1; // Fixed part is 1 byte
} else {
len += 2; // Fixed part is 2 bytes
}
len += header->N_li * 1.5 + 0.5; // Extension part - integer rounding up
return len;
}
bool rlc_um_start_aligned(uint8_t fi)
{
return (fi == RLC_FI_FIELD_START_AND_END_ALIGNED || fi == RLC_FI_FIELD_NOT_END_ALIGNED);
}
bool rlc_um_end_aligned(uint8_t fi)
{
return (fi == RLC_FI_FIELD_START_AND_END_ALIGNED || fi == RLC_FI_FIELD_NOT_START_ALIGNED);
}
} // namespace srslte
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