srsRAN_4G/lib/include/srsran/interfaces/enb_rrc_interfaces.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.
 *
 */

#include "srsenb/hdr/stack/mac/sched_interface.h"
#include "srsran/asn1/s1ap_utils.h"
#include "srsran/interfaces/enb_rrc_interface_types.h"

#ifndef SRSRAN_ENB_RRC_INTERFACES_H
#define SRSRAN_ENB_RRC_INTERFACES_H

namespace srsenb {

// RRC interface for S1AP
class rrc_interface_s1ap
{
public:
  using failed_erab_list = std::map<uint32_t, asn1::s1ap::cause_c>;

  virtual void write_dl_info(uint16_t rnti, srsran::unique_byte_buffer_t sdu)                    = 0;
  virtual void release_ue(uint16_t rnti)                                                         = 0;
  virtual bool setup_ue_ctxt(uint16_t rnti, const asn1::s1ap::init_context_setup_request_s& msg) = 0;
  virtual bool modify_ue_ctxt(uint16_t rnti, const asn1::s1ap::ue_context_mod_request_s& msg)    = 0;
  virtual bool has_erab(uint16_t rnti, uint32_t erab_id) const                                   = 0;
  virtual bool release_erabs(uint32_t rnti)                                                      = 0;

  virtual int  get_erab_addr_in(uint16_t rnti, uint16_t erab_id, transp_addr_t& addr_in, uint32_t& teid_in) const  = 0;
  virtual void set_aggregate_max_bitrate(uint16_t rnti, const asn1::s1ap::ue_aggregate_maximum_bitrate_s& bitrate) = 0;

  /**
   * TS 36.413, 8.2.1 and 8.3.1 - Setup E-RAB / Initial Context Setup
   * @return if error, cause argument is updated with cause
   */
  virtual int setup_erab(uint16_t                                   rnti,
                         uint16_t                                   erab_id,
                         const asn1::s1ap::erab_level_qos_params_s& qos_params,
                         srsran::const_span<uint8_t>                nas_pdu,
                         const transp_addr_t&                       addr,
                         uint32_t                                   gtpu_teid_out,
                         asn1::s1ap::cause_c&                       cause) = 0;
  /**
   * TS 36.413, 8.2.2 - Modify E-RAB
   * @return if error, cause argument is updated with cause
   */
  virtual int modify_erab(uint16_t                                   rnti,
                          uint16_t                                   erab_id,
                          const asn1::s1ap::erab_level_qos_params_s& qos_params,
                          srsran::const_span<uint8_t>                nas_pdu,
                          asn1::s1ap::cause_c&                       cause) = 0;
  /**
   * TS 36.413, 8.2.3 - Release E-RAB id
   * @return error if E-RAB id or rnti were not found
   */
  virtual int release_erab(uint16_t rnti, uint16_t erab_id) = 0;

  virtual void add_paging_id(uint32_t ueid, const asn1::s1ap::ue_paging_id_c& ue_paging_id) = 0;

  /// TS 36.413, 8.2.1, 8.2.2, 8.2.3 - Notify UE of ERAB updates (done via RRC Reconfiguration Message)
  virtual int notify_ue_erab_updates(uint16_t rnti, srsran::const_span<uint8_t> nas_pdu) = 0;

  /**
   * Reports the reception of S1 HandoverCommand / HandoverPreparationFailure or abnormal conditions during
   * S1 Handover preparation back to RRC.
   *
   * @param rnti user
   * @param is_success true if ho cmd was received
   * @param container TargeteNB RRCConnectionReconfiguration message with MobilityControlInfo
   */
  enum class ho_prep_result { success, failure, timeout };
  virtual void ho_preparation_complete(uint16_t                     rnti,
                                       ho_prep_result               result,
                                       const asn1::s1ap::ho_cmd_s&  msg,
                                       srsran::unique_byte_buffer_t container) = 0;
  virtual uint16_t
               start_ho_ue_resource_alloc(const asn1::s1ap::ho_request_s&                                   msg,
                                          const asn1::s1ap::sourceenb_to_targetenb_transparent_container_s& container,
                                          asn1::s1ap::cause_c&                                              failure_cause)                                     = 0;
  virtual void set_erab_status(uint16_t rnti, const asn1::s1ap::bearers_subject_to_status_transfer_list_l& erabs) = 0;
};

/// RRC interface for RLC
class rrc_interface_rlc
{
public:
  virtual void max_retx_attempted(uint16_t rnti)                                         = 0;
  virtual void protocol_failure(uint16_t rnti)                                           = 0;
  virtual void write_pdu(uint16_t rnti, uint32_t lcid, srsran::unique_byte_buffer_t sdu) = 0;
};

/// RRC interface for MAC
class rrc_interface_mac
{
public:
  /* Radio Link failure */
  virtual int  add_user(uint16_t rnti, const sched_interface::ue_cfg_t& init_ue_cfg)      = 0;
  virtual void upd_user(uint16_t new_rnti, uint16_t old_rnti)                             = 0;
  virtual void set_activity_user(uint16_t rnti)                                           = 0;
  virtual void set_radiolink_dl_state(uint16_t rnti, bool crc_res)                        = 0;
  virtual void set_radiolink_ul_state(uint16_t rnti, bool crc_res)                        = 0;
  virtual bool is_paging_opportunity(uint32_t tti_tx_dl, uint32_t* payload_len)           = 0;
  virtual void read_pdu_pcch(uint32_t tti_tx_dl, uint8_t* payload, uint32_t payload_size) = 0;

  ///< Provide packed SIB to MAC (buffer is managed by RRC)
  virtual uint8_t* read_pdu_bcch_dlsch(const uint8_t enb_cc_idx, const uint32_t sib_index) = 0;
};

/// RRC interface for PDCP
class rrc_interface_pdcp
{
public:
  virtual void write_pdu(uint16_t rnti, uint32_t lcid, srsran::unique_byte_buffer_t pdu) = 0;
  virtual void notify_pdcp_integrity_error(uint16_t rnti, uint32_t lcid)                 = 0;
};

// RRC interfaces for NSA operation

/// X2AP inspired interface to allow EUTRA RRC to call NR RRC
class rrc_nr_interface_rrc
{
public:
  struct sgnb_addition_req_params_t {
    uint32_t eps_bearer_id;
    // add configuration check
    // E-RAB Parameters, Tunnel address (IP address, TEID)
    // QCI, security, etc
  };

  /// Request addition of NR carrier for UE
  virtual int sgnb_addition_request(uint16_t eutra_rnti, const sgnb_addition_req_params_t& params) = 0;

  /// Provide information whether the requested configuration was applied successfully by the UE
  virtual int sgnb_reconfiguration_complete(uint16_t eutra_rnti, asn1::dyn_octstring reconfig_response) = 0;
};

/// X2AP inspired interface for response from NR RRC to EUTRA RRC
class rrc_eutra_interface_rrc_nr
{
public:
  /**
   * @brief List of parameters included in the SgNB addition Ack message
   * @param nr_secondary_cell_group_cfg_r15 Encoded part of the RRC Reconfiguration
   * @param nr_radio_bearer_cfg1_r15 Encoded part of the RRC Reconfiguration
   * @param eps_bearer_id ID of the transfered bearer
   */
  struct sgnb_addition_ack_params_t {
    uint16_t            nr_rnti = SRSRAN_INVALID_RNTI; // RNTI that was assigned to the UE
    asn1::dyn_octstring nr_secondary_cell_group_cfg_r15;
    asn1::dyn_octstring nr_radio_bearer_cfg1_r15;
    uint32_t            eps_bearer_id = 0; // (list of) successfully transfered EPS bearers
  };

  /**
   * @brief Signal successful addition of UE
   *
   * @param eutra_rnti The RNTI that the EUTRA RRC used to request the SgNB addition
   * @param params Parameter list
   */
  virtual void sgnb_addition_ack(uint16_t eutra_rnti, sgnb_addition_ack_params_t params) = 0;

  /**
   * @brief Signal unsuccessful SgNB addition
   *
   * @param eutra_rnti The RNTI that the EUTRA RRC used to request the SgNB addition
   */
  virtual void sgnb_addition_reject(uint16_t eutra_rnti) = 0;

  /**
   * @brief Signal completion of SgNB addition after UE (with new NR identity) has attached
   *
   * @param eutra_rnti The RNTI that the EUTRA RRC used to request the SgNB addition
   * @param nr_rnti    The RNTI that has been assigned to the UE on the SgNB
   */
  virtual void sgnb_addition_complete(uint16_t eutra_rnti, uint16_t nr_rnti) = 0;
};

} // namespace srsenb

#endif // SRSRAN_ENB_RRC_INTERFACES_H