srsLTE/lib/include/srsran/rlc/rlc_am_nr_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_NR_PACKING_H
#define SRSRAN_RLC_AM_NR_PACKING_H

#include "srsran/common/string_helpers.h"
#include "srsran/rlc/rlc_am_base.h"
#include <set>

namespace srsran {

const uint32_t RLC_AM_NR_WINDOW_SIZE_12BIT = 4096;
const uint32_t RLC_AM_NR_WINDOW_SIZE_18BIT = 262144;
const uint32_t INVALID_RLC_SN              = 0xFFFFFFFF;
const uint32_t RETX_COUNT_NOT_STARTED      = 0xFFFFFFFF;

///< AM NR PDU header
struct rlc_am_nr_pdu_header_t {
  rlc_am_nr_pdu_header_t()                                = default;
  rlc_am_nr_pdu_header_t(const rlc_am_nr_pdu_header_t& h) = default;
  rlc_am_nr_pdu_header_t& operator=(const rlc_am_nr_pdu_header_t&) = default;
  rlc_am_nr_pdu_header_t(rlc_am_nr_pdu_header_t&& h)               = default;
  ~rlc_am_nr_pdu_header_t()                                        = default;

  rlc_am_nr_pdu_header_t& operator=(rlc_am_nr_pdu_header_t&& h) = default;

  rlc_dc_field_t      dc      = {}; ///< Data/Control (D/C) field
  uint8_t             p       = {}; ///< Polling bit
  rlc_nr_si_field_t   si      = {}; ///< Segmentation info
  rlc_am_nr_sn_size_t sn_size = {}; ///< Sequence number size (12 or 18 bits)
  uint32_t            sn      = {}; ///< Sequence number
  uint16_t            so      = {}; ///< Sequence offset
};

struct rlc_amd_pdu_nr_t {
  rlc_am_nr_pdu_header_t header;
  unique_byte_buffer_t   buf;
};

struct rlc_amd_rx_pdu_nr {
  rlc_am_nr_pdu_header_t header = {};
  unique_byte_buffer_t   buf    = nullptr;
  uint32_t               rlc_sn = {};

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

struct rlc_amd_rx_pdu_nr_cmp {
  bool operator()(const rlc_amd_rx_pdu_nr& a, const rlc_amd_rx_pdu_nr& b) const { return a.header.so < b.header.so; }
};

struct rlc_amd_rx_sdu_nr_t {
  uint32_t             rlc_sn         = 0;
  bool                 fully_received = false;
  unique_byte_buffer_t buf;
  using segment_list_t = std::set<rlc_amd_rx_pdu_nr, rlc_amd_rx_pdu_nr_cmp>;
  segment_list_t segments;

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

struct rlc_amd_tx_sdu_nr_t {
  uint32_t             rlc_sn = INVALID_RLC_SN;
  unique_byte_buffer_t buf;

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

///< AM NR Status PDU header (perhaps merge with LTE version)
typedef struct {
  rlc_am_nr_control_pdu_type_t cpt;
  uint32_t                     ack_sn; ///< SN of the next not received RLC Data PDU
  uint16_t                     N_nack; ///< number of NACKs
  uint8_t           nack_range;        ///< number of consecutively lost RLC SDUs starting from and including NACK_SN
  rlc_status_nack_t nacks[RLC_AM_NR_WINDOW_SIZE_12BIT];
} rlc_am_nr_status_pdu_t;

/****************************************************************************
 * Header pack/unpack helper functions for NR
 * Ref: 3GPP TS 38.322 v15.3.0 Section 6.2.2.3
 ***************************************************************************/
uint32_t rlc_am_nr_read_data_pdu_header(const byte_buffer_t*      pdu,
                                        const rlc_am_nr_sn_size_t sn_size,
                                        rlc_am_nr_pdu_header_t*   header);

uint32_t rlc_am_nr_read_data_pdu_header(const uint8_t*            payload,
                                        const uint32_t            nof_bytes,
                                        const rlc_am_nr_sn_size_t sn_size,
                                        rlc_am_nr_pdu_header_t*   header);

uint32_t rlc_am_nr_write_data_pdu_header(const rlc_am_nr_pdu_header_t& header, uint8_t* payload);
uint32_t rlc_am_nr_write_data_pdu_header(const rlc_am_nr_pdu_header_t& header, byte_buffer_t* pdu);

uint32_t rlc_am_nr_packed_length(const rlc_am_nr_pdu_header_t& header);

uint32_t
rlc_am_nr_read_status_pdu(const byte_buffer_t* pdu, const rlc_am_nr_sn_size_t sn_size, rlc_am_nr_status_pdu_t* status);

uint32_t rlc_am_nr_read_status_pdu(const uint8_t*            payload,
                                   const uint32_t            nof_bytes,
                                   const rlc_am_nr_sn_size_t sn_size,
                                   rlc_am_nr_status_pdu_t*   status);

int32_t rlc_am_nr_write_status_pdu(const rlc_am_nr_status_pdu_t& status_pdu,
                                   const rlc_am_nr_sn_size_t     sn_size,
                                   byte_buffer_t*                pdu);

/**
 * Logs Status PDU into provided log channel, using fmt_str as format string
 */
template <typename... Args>
void log_rlc_am_nr_status_pdu_to_string(srslog::log_channel&    log_ch,
                                        const char*             fmt_str,
                                        rlc_am_nr_status_pdu_t* status,
                                        const std::string&      rb_name,
                                        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));
}

/*
 * Log NR AMD PDUs
 */
inline void log_rlc_am_nr_pdu_header_to_string(srslog::log_channel&          log_ch,
                                               const rlc_am_nr_pdu_header_t& header,
                                               const std::string&            rb_name)
{
  if (not log_ch.enabled()) {
    return;
  }
  fmt::memory_buffer buffer;
  fmt::format_to(buffer,
                 "{}: [{}, P={}, SI={}, SN_SIZE={}, SN={}, SO={}",
                 rb_name,
                 rlc_dc_field_text[header.dc],
                 (header.p ? "1" : "0"),
                 to_string_short(header.si),
                 header.sn,
                 header.sn,
                 header.so);
  fmt::format_to(buffer, "]");

  log_ch("%s", to_c_str(buffer));
}
} // namespace srsran

#endif // SRSRAN_RLC_AM_NR_PACKING_H