srsRAN_4G/lib/include/srsran/rlc/rlc_am_lte_packing.h

/**
 *
 * \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.
 *
 */

#ifndef SRSRAN_RLC_AM_LTE_PACKING_H
#define SRSRAN_RLC_AM_LTE_PACKING_H

#include "srsran/common/string_helpers.h"
#include "srsran/rlc/rlc_am_base.h"
#include "srsran/rlc/rlc_am_data_structs.h" // required for rlc_am_pdu_segment
#include <list>

namespace srsran {

/// Class that contains the parameters and state (e.g. segments) of a RLC PDU
class rlc_amd_tx_pdu
{
  using list_type                      = intrusive_forward_list<rlc_am_pdu_segment>;
  const static uint32_t invalid_rlc_sn = std::numeric_limits<uint32_t>::max();

  list_type list;

public:
  using iterator       = typename list_type::iterator;
  using const_iterator = typename list_type::const_iterator;

  const uint32_t       rlc_sn     = invalid_rlc_sn;
  uint32_t             retx_count = 0;
  rlc_amd_pdu_header_t header;
  unique_byte_buffer_t buf;

  explicit rlc_amd_tx_pdu(uint32_t rlc_sn_) : rlc_sn(rlc_sn_) {}
  rlc_amd_tx_pdu(const rlc_amd_tx_pdu&)           = delete;
  rlc_amd_tx_pdu(rlc_amd_tx_pdu&& other) noexcept = default;
  rlc_amd_tx_pdu& operator=(const rlc_amd_tx_pdu& other) = delete;
  rlc_amd_tx_pdu& operator=(rlc_amd_tx_pdu&& other) = delete;
  ~rlc_amd_tx_pdu();

  // Segment List Interface
  void           add_segment(rlc_am_pdu_segment& segment) { list.push_front(&segment); }
  const_iterator begin() const { return list.begin(); }
  const_iterator end() const { return list.end(); }
  iterator       begin() { return list.begin(); }
  iterator       end() { return list.end(); }
};

struct rlc_amd_retx_t {
  uint32_t sn;
  bool     is_segment;
  uint32_t so_start;
  uint32_t so_end;
};

struct rlc_sn_info_t {
  uint32_t sn;
  bool     is_acked;
};

struct rlc_amd_rx_pdu {
  rlc_amd_pdu_header_t header;
  unique_byte_buffer_t buf;
  uint32_t             rlc_sn;

  rlc_amd_rx_pdu() = default;
  explicit rlc_amd_rx_pdu(uint32_t rlc_sn_) : rlc_sn(rlc_sn_) {}
};

struct rlc_amd_rx_pdu_segments_t {
  std::list<rlc_amd_rx_pdu> segments;
};

/****************************************************************************
 * Header pack/unpack helper functions
 * Ref: 3GPP TS 36.322 v10.0.0 Section 6.2.1
 ***************************************************************************/
void rlc_am_read_data_pdu_header(byte_buffer_t* pdu, rlc_amd_pdu_header_t* header);
void rlc_am_read_data_pdu_header(uint8_t** payload, uint32_t* nof_bytes, rlc_amd_pdu_header_t* header);
void rlc_am_write_data_pdu_header(rlc_amd_pdu_header_t* header, byte_buffer_t* pdu);
void rlc_am_write_data_pdu_header(rlc_amd_pdu_header_t* header, uint8_t** payload);
void rlc_am_read_status_pdu(byte_buffer_t* pdu, rlc_status_pdu_t* status);
void rlc_am_read_status_pdu(uint8_t* payload, uint32_t nof_bytes, rlc_status_pdu_t* status);
void rlc_am_write_status_pdu(rlc_status_pdu_t* status, byte_buffer_t* pdu);
int  rlc_am_write_status_pdu(rlc_status_pdu_t* status, uint8_t* payload);

uint32_t    rlc_am_packed_length(rlc_amd_pdu_header_t* header);
uint32_t    rlc_am_packed_length(rlc_status_pdu_t* status);
uint32_t    rlc_am_packed_length(rlc_amd_retx_t retx);
bool        rlc_am_is_pdu_segment(uint8_t* payload);
bool        rlc_am_is_valid_status_pdu(const rlc_status_pdu_t& status, uint32_t rx_win_min = 0);
std::string rlc_am_undelivered_sdu_info_to_string(const std::map<uint32_t, pdcp_pdu_info>& info_queue);
void        log_rlc_amd_pdu_header_to_string(srslog::log_channel& log_ch, const rlc_amd_pdu_header_t& header);
bool        rlc_am_start_aligned(const uint8_t fi);
bool        rlc_am_end_aligned(const uint8_t fi);
bool        rlc_am_is_unaligned(const uint8_t fi);
bool        rlc_am_not_start_aligned(const uint8_t fi);

/**
 * Logs Status PDU into provided log channel, using fmt_str as format string
 */
template <typename... Args>
void log_rlc_am_status_pdu_to_string(srslog::log_channel& log_ch,
                                     const char*          fmt_str,
                                     rlc_status_pdu_t*    status,
                                     Args&&... args)
{
  if (not log_ch.enabled()) {
    return;
  }
  fmt::memory_buffer buffer;
  fmt::format_to(buffer, "ACK_SN = {}, N_nack = {}", status->ack_sn, status->N_nack);
  if (status->N_nack > 0) {
    fmt::format_to(buffer, ", NACK_SN = ");
    for (uint32_t i = 0; i < status->N_nack; ++i) {
      if (status->nacks[i].has_so) {
        fmt::format_to(
            buffer, "[{} {}:{}]", status->nacks[i].nack_sn, status->nacks[i].so_start, status->nacks[i].so_end);
      } else {
        fmt::format_to(buffer, "[{}]", status->nacks[i].nack_sn);
      }
    }
  }
  log_ch(fmt_str, std::forward<Args>(args)..., to_c_str(buffer));
}

} // namespace srsran

#endif // SRSRAN_RLC_AM_LTE_PACKING_H