srsRAN_4G/lib/src/rlc/rlc_tm.cc

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2021 Software Radio Systems Limited
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the distribution.
 *
 */

#include "srsran/rlc/rlc_tm.h"
#include "srsran/common/common_lte.h"
#include "srsran/interfaces/ue_pdcp_interfaces.h"
#include "srsran/interfaces/ue_rrc_interfaces.h"

namespace srsran {

rlc_tm::rlc_tm(srslog::basic_logger&      logger,
               uint32_t                   lcid_,
               srsue::pdcp_interface_rlc* pdcp_,
               srsue::rrc_interface_rlc*  rrc_) :
  logger(logger), pdcp(pdcp_), rrc(rrc_), lcid(lcid_)
{
  pool = byte_buffer_pool::get_instance();
}

// Warning: must call stop() to properly deallocate all buffers
rlc_tm::~rlc_tm()
{
  pool = NULL;
}

bool rlc_tm::configure(const rlc_config_t& cnfg)
{
  logger.error("Attempted to configure TM RLC entity");
  return true;
}

void rlc_tm::empty_queue()
{
  // Drop all messages in TX queue
  unique_byte_buffer_t buf;
  while (ul_queue.try_read(&buf)) {
  }
  ul_queue.reset();
}

void rlc_tm::reestablish()
{
  stop();
  tx_enabled = true;
}

void rlc_tm::stop()
{
  tx_enabled = false;
  empty_queue();
}

rlc_mode_t rlc_tm::get_mode()
{
  return rlc_mode_t::tm;
}

uint32_t rlc_tm::get_bearer()
{
  return lcid;
}

// PDCP interface
void rlc_tm::write_sdu(unique_byte_buffer_t sdu)
{
  if (!tx_enabled) {
    return;
  }
  if (sdu != nullptr) {
    uint8_t*                                 msg_ptr   = sdu->msg;
    uint32_t                                 nof_bytes = sdu->N_bytes;
    srsran::error_type<unique_byte_buffer_t> ret       = ul_queue.try_write(std::move(sdu));
    if (ret) {
      logger.info(msg_ptr,
                  nof_bytes,
                  "%s Tx SDU, queue size=%d, bytes=%d",
                  rrc->get_rb_name(lcid),
                  ul_queue.size(),
                  ul_queue.size_bytes());
    } else {
      logger.warning(ret.error()->msg,
                     ret.error()->N_bytes,
                     "[Dropped SDU] %s Tx SDU, queue size=%d, bytes=%d",
                     rrc->get_rb_name(lcid),
                     ul_queue.size(),
                     ul_queue.size_bytes());
    }

  } else {
    logger.warning("NULL SDU pointer in write_sdu()");
  }
}

void rlc_tm::discard_sdu(uint32_t discard_sn)
{
  if (!tx_enabled) {
    return;
  }
  logger.warning("SDU discard not implemented on RLC TM");
}

bool rlc_tm::sdu_queue_is_full()
{
  return ul_queue.is_full();
}

// MAC interface
bool rlc_tm::has_data()
{
  return not ul_queue.is_empty();
}

uint32_t rlc_tm::get_buffer_state()
{
  return ul_queue.size_bytes();
}

rlc_bearer_metrics_t rlc_tm::get_metrics()
{
  std::lock_guard<std::mutex> lock(metrics_mutex);
  return metrics;
}

void rlc_tm::reset_metrics()
{
  std::lock_guard<std::mutex> lock(metrics_mutex);
  metrics = {};
}

uint32_t rlc_tm::read_pdu(uint8_t* payload, uint32_t nof_bytes)
{
  uint32_t pdu_size = ul_queue.size_tail_bytes();
  if (pdu_size > nof_bytes) {
    logger.info("%s Tx PDU size larger than MAC opportunity (%d > %d)", rrc->get_rb_name(lcid), pdu_size, nof_bytes);
    return 0;
  }
  unique_byte_buffer_t buf;
  if (ul_queue.try_read(&buf)) {
    pdu_size = buf->N_bytes;
    memcpy(payload, buf->msg, buf->N_bytes);
    logger.debug("%s Complete SDU scheduled for tx. Stack latency: %" PRIu64 " us",
                 rrc->get_rb_name(lcid),
                 (uint64_t)buf->get_latency_us().count());
    logger.info(payload,
                pdu_size,
                "%s Tx %s PDU, queue size=%d, bytes=%d",
                rrc->get_rb_name(lcid),
                srsran::to_string(rlc_mode_t::tm),
                ul_queue.size(),
                ul_queue.size_bytes());

    std::lock_guard<std::mutex> lock(metrics_mutex);
    metrics.num_tx_pdu_bytes += pdu_size;
    return pdu_size;
  } else {
    logger.warning("Queue empty while trying to read");
    if (ul_queue.size_bytes() > 0) {
      logger.warning("Corrupted queue: empty but size_bytes > 0. Resetting queue");
      ul_queue.reset();
    }
    return 0;
  }
}

void rlc_tm::write_pdu(uint8_t* payload, uint32_t nof_bytes)
{
  unique_byte_buffer_t buf = make_byte_buffer();
  if (buf != nullptr) {
    memcpy(buf->msg, payload, nof_bytes);
    buf->N_bytes = nof_bytes;
    buf->set_timestamp();
    {
      std::lock_guard<std::mutex> lock(metrics_mutex);
      metrics.num_rx_pdu_bytes += nof_bytes;
      metrics.num_rx_pdus++;
    }
    if (srsran::srb_to_lcid(srsran::lte_srb::srb0) == lcid) {
      rrc->write_pdu(lcid, std::move(buf));
    } else {
      pdcp->write_pdu(lcid, std::move(buf));
    }
  } else {
    logger.error("Fatal Error: Couldn't allocate buffer in rlc_tm::write_pdu().");
  }
}

} // namespace srsran