srsLTE/srsenb/hdr/stack/s1ap/s1ap.h

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C++

/**
* Copyright 2013-2022 Software Radio Systems Limited
*
* This file is part of srsRAN.
*
* srsRAN 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.
*
* srsRAN 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/.
*
*/
#ifndef SRSENB_S1AP_H
#define SRSENB_S1AP_H
#include <map>
#include "srsenb/hdr/common/common_enb.h"
#include "srsran/adt/circular_map.h"
#include "srsran/common/buffer_pool.h"
#include "srsran/common/common.h"
#include "srsran/common/s1ap_pcap.h"
#include "srsran/common/threads.h"
#include "srsran/interfaces/enb_interfaces.h"
#include "srsran/interfaces/enb_s1ap_interfaces.h"
#include "s1ap_metrics.h"
#include "srsran/adt/optional.h"
#include "srsran/asn1/s1ap.h"
#include "srsran/common/network_utils.h"
#include "srsran/common/stack_procedure.h"
#include "srsran/common/task_scheduler.h"
#include "srsran/srslog/srslog.h"
#include <unordered_map>
namespace srsenb {
class rrc_interface_s1ap;
struct ue_ctxt_t {
static const uint32_t invalid_enb_id = std::numeric_limits<uint32_t>::max();
uint16_t rnti = SRSRAN_INVALID_RNTI;
uint32_t enb_ue_s1ap_id = invalid_enb_id;
srsran::optional<uint32_t> mme_ue_s1ap_id;
uint32_t enb_cc_idx = 0;
struct timeval init_timestamp = {};
};
class s1ap : public s1ap_interface_rrc
{
using s1ap_proc_id_t = asn1::s1ap::s1ap_elem_procs_o::init_msg_c::types_opts::options;
public:
using erab_id_list = srsran::bounded_vector<uint16_t, ASN1_S1AP_MAXNOOF_ERABS>;
using erab_item_list = srsran::bounded_vector<asn1::s1ap::erab_item_s, ASN1_S1AP_MAXNOOF_ERABS>;
s1ap(srsran::task_sched_handle task_sched_,
srslog::basic_logger& logger,
srsran::socket_manager_itf* rx_socket_handler);
int init(const s1ap_args_t& args_, rrc_interface_s1ap* rrc_);
void stop();
void get_metrics(s1ap_metrics_t& m);
// RRC interface
void initial_ue(uint16_t rnti,
uint32_t enb_cc_idx,
asn1::s1ap::rrc_establishment_cause_e cause,
srsran::unique_byte_buffer_t pdu) override;
void initial_ue(uint16_t rnti,
uint32_t enb_cc_idx,
asn1::s1ap::rrc_establishment_cause_e cause,
srsran::unique_byte_buffer_t pdu,
uint32_t m_tmsi,
uint8_t mmec) override;
void write_pdu(uint16_t rnti, srsran::unique_byte_buffer_t pdu) override;
bool user_exists(uint16_t rnti) override;
void user_mod(uint16_t old_rnti, uint16_t new_rnti) override;
bool user_release(uint16_t rnti, asn1::s1ap::cause_radio_network_e cause_radio) override;
void notify_rrc_reconf_complete(uint16_t rnti) override;
bool is_mme_connected() override;
bool send_ho_required(uint16_t rnti,
uint32_t target_eci,
uint16_t target_tac,
srsran::plmn_id_t target_plmn,
srsran::span<uint32_t> fwd_erabs,
srsran::unique_byte_buffer_t rrc_container,
bool has_direct_fwd_path) override;
bool send_enb_status_transfer_proc(uint16_t rnti, std::vector<bearer_status_info>& bearer_status_list) override;
bool send_ho_req_ack(const asn1::s1ap::ho_request_s& msg,
uint16_t rnti,
uint32_t enb_cc_idx,
srsran::unique_byte_buffer_t ho_cmd,
srsran::span<asn1::s1ap::erab_admitted_item_s> admitted_bearers,
srsran::const_span<asn1::s1ap::erab_item_s> not_admitted_bearers) override;
void send_ho_cancel(uint16_t rnti, const asn1::s1ap::cause_c& cause) override;
bool release_erabs(uint16_t rnti, const std::vector<uint16_t>& erabs_successfully_released) override;
bool send_error_indication(const asn1::s1ap::cause_c& cause,
srsran::optional<uint32_t> enb_ue_s1ap_id = {},
srsran::optional<uint32_t> mme_ue_s1ap_id = {});
bool send_ue_cap_info_indication(uint16_t rnti, srsran::unique_byte_buffer_t ue_radio_cap) override;
/// Target eNB Handover
/// Section 8.4.2 - Handover Resource Allocation
void send_ho_failure(uint32_t mme_ue_s1ap_id, const asn1::s1ap::cause_c& cause);
/// Section 8.4.3 - Handover Notification
void send_ho_notify(uint16_t rnti, uint64_t target_eci) override;
// Stack interface
bool
handle_mme_rx_msg(srsran::unique_byte_buffer_t pdu, const sockaddr_in& from, const sctp_sndrcvinfo& sri, int flags);
void start_pcap(srsran::s1ap_pcap* pcap_);
private:
static const int MME_PORT = 36412;
static const int ADDR_FAMILY = AF_INET;
static const int SOCK_TYPE = SOCK_STREAM;
static const int PROTO = IPPROTO_SCTP;
static const int PPID = 18;
static const int NONUE_STREAM_ID = 0;
// args
rrc_interface_s1ap* rrc = nullptr;
s1ap_args_t args;
srslog::basic_logger& logger;
srslog::log_channel& alarms_channel;
srsran::task_sched_handle task_sched;
srsran::task_queue_handle mme_task_queue;
srsran::socket_manager_itf* rx_socket_handler;
srsran::unique_socket mme_socket;
struct sockaddr_in mme_addr = {}; // MME address
bool mme_connected = false;
bool running = false;
uint32_t next_enb_ue_s1ap_id = 1; // Next ENB-side UE identifier
uint16_t next_ue_stream_id = 1; // Next UE SCTP stream identifier
srsran::unique_timer mme_connect_timer, s1setup_timeout;
// Protocol IEs sent with every UL S1AP message
asn1::s1ap::tai_s tai;
asn1::s1ap::eutran_cgi_s eutran_cgi;
// PCAP
srsran::s1ap_pcap* pcap = nullptr;
asn1::s1ap::s1_setup_resp_s s1setupresponse;
void build_tai_cgi();
bool connect_mme();
bool setup_s1();
bool sctp_send_s1ap_pdu(const asn1::s1ap::s1ap_pdu_c& tx_pdu, uint32_t rnti, const char* procedure_name);
bool handle_s1ap_rx_pdu(srsran::byte_buffer_t* pdu);
bool handle_initiatingmessage(const asn1::s1ap::init_msg_s& msg);
bool handle_successfuloutcome(const asn1::s1ap::successful_outcome_s& msg);
bool handle_unsuccessfuloutcome(const asn1::s1ap::unsuccessful_outcome_s& msg);
bool handle_paging(const asn1::s1ap::paging_s& msg);
bool handle_s1setupresponse(const asn1::s1ap::s1_setup_resp_s& msg);
bool handle_dlnastransport(const asn1::s1ap::dl_nas_transport_s& msg);
bool handle_initialctxtsetuprequest(const asn1::s1ap::init_context_setup_request_s& msg);
bool handle_uectxtreleasecommand(const asn1::s1ap::ue_context_release_cmd_s& msg);
bool handle_s1setupfailure(const asn1::s1ap::s1_setup_fail_s& msg);
bool handle_erabsetuprequest(const asn1::s1ap::erab_setup_request_s& msg);
bool handle_erabmodifyrequest(const asn1::s1ap::erab_modify_request_s& msg);
bool handle_erabreleasecommand(const asn1::s1ap::erab_release_cmd_s& msg);
bool handle_uecontextmodifyrequest(const asn1::s1ap::ue_context_mod_request_s& msg);
void ue_ctxt_setup_complete(uint16_t rnti);
// handover
/**
* Source eNB Handler for S1AP "HANDOVER PREPARATION FAILURE" Message
* MME ---> Source eNB
* @remark TS 36.413, 8.4.1.3 - S1AP Procedures | Handover Signalling | Handover Preparation | Unsuccessful Operation
* @param msg HANDOVER COMMAND S1AP PDU
* @return true if the HANDOVER COMMAND content is valid. False otherwise
*/
bool handle_handover_preparation_failure(const asn1::s1ap::ho_prep_fail_s& msg);
/**
* Source eNB Handler for S1AP "HANDOVER COMMAND" Message
* MME ---> Source eNB
* @remark TS 36.413, 8.4.1.2 - S1AP Procedures | Handover Signalling | Handover Preparation | Successful Operation
* @param msg HANDOVER COMMAND S1AP PDU
* @return true if the HANDOVER COMMAND content is valid. False otherwise
*/
bool handle_handover_command(const asn1::s1ap::ho_cmd_s& msg);
/**
* Target eNB Handler for S1AP "HANDOVER REQUEST" Message
* MME ---> Target eNB
* @remark TS 36.413, 8.4.7.2 - S1AP Procedures | Handover Signalling | Handover Resource Allocation
* @param msg HANDOVER REQUEST S1AP PDU
* @return true if the new user resources were successfully allocated
*/
bool handle_handover_request(const asn1::s1ap::ho_request_s& msg);
/**
* Target eNB Handler for S1AP "MME STATUS TRANSFER" Message
* MME ---> Target eNB
* @remark TS 36.413, 8.4.7.2 - S1AP Procedures | Handover Signalling | MME Status Transfer | Successful Operation
* @param msg MME STATUS TRANSFER S1AP PDU
* @return true if the msg content is valid. False otherwise
*/
bool handle_mme_status_transfer(const asn1::s1ap::mme_status_transfer_s& msg);
// UE-specific data and procedures
struct ue {
//! TS 36.413, Section 8.4.1 - Handover Preparation Procedure
class ho_prep_proc_t
{
public:
struct ts1_reloc_prep_expired {};
ho_prep_proc_t(s1ap::ue* ue_);
srsran::proc_outcome_t init(uint32_t target_eci_,
uint16_t target_tac_,
srsran::plmn_id_t target_plmn_,
srsran::span<uint32_t> fwd_erabs,
srsran::unique_byte_buffer_t rrc_container,
bool has_direct_fwd_path);
srsran::proc_outcome_t step() { return srsran::proc_outcome_t::yield; }
srsran::proc_outcome_t react(ts1_reloc_prep_expired e);
srsran::proc_outcome_t react(const asn1::s1ap::ho_prep_fail_s& msg);
srsran::proc_outcome_t react(const asn1::s1ap::ho_cmd_s& msg);
void then(const srsran::proc_state_t& result);
const char* name() { return "HandoverPreparation"; }
private:
s1ap::ue* ue_ptr = nullptr;
s1ap* s1ap_ptr = nullptr;
uint32_t target_eci = 0;
uint16_t target_tac = 0;
srsran::plmn_id_t target_plmn;
srsran::unique_byte_buffer_t rrc_container;
const asn1::s1ap::ho_cmd_s* ho_cmd_msg = nullptr;
};
explicit ue(s1ap* s1ap_ptr_);
bool send_enb_status_transfer_proc(std::vector<bearer_status_info>& bearer_status_list);
bool send_ulnastransport(srsran::unique_byte_buffer_t pdu);
bool send_uectxtreleaserequest(const asn1::s1ap::cause_c& cause);
bool send_uectxtmodifyfailure(const asn1::s1ap::cause_c& cause);
bool send_uectxtmodifyresp();
bool send_uectxtreleasecomplete();
bool send_initialuemessage(asn1::s1ap::rrc_establishment_cause_e cause,
srsran::unique_byte_buffer_t pdu,
bool has_tmsi,
uint32_t m_tmsi = 0,
uint8_t mmec = 0);
void ue_ctxt_setup_complete();
void notify_rrc_reconf_complete();
bool send_erab_setup_response(const erab_id_list& erabs_setup, const erab_item_list& erabs_failed);
bool send_erab_release_response(const erab_id_list& erabs_released, const erab_item_list& erabs_failed);
bool send_erab_modify_response(const erab_id_list& erabs_modified, const erab_item_list& erabs_failed);
bool send_erab_release_indication(const std::vector<uint16_t>& erabs_successfully_released);
bool send_ue_cap_info_indication(srsran::unique_byte_buffer_t ue_radio_cap);
/// TS 36.413 8.4.5 - Handover Cancellation
void send_ho_cancel(const asn1::s1ap::cause_c& cause);
bool was_uectxtrelease_requested() const { return release_requested; }
void
set_state(s1ap_proc_id_t state, const erab_id_list& erabs_updated, const erab_item_list& erabs_failed_to_update);
s1ap_proc_id_t get_state() const { return current_state; }
ue_ctxt_t ctxt = {};
uint16_t stream_id = 1;
private:
bool send_ho_required(uint32_t target_eci_,
uint16_t target_tac_,
srsran::plmn_id_t target_plmn_,
srsran::span<uint32_t> fwd_erabs,
srsran::unique_byte_buffer_t rrc_container,
bool has_direct_fwd_path);
void get_erab_addr(uint16_t erab_id, transp_addr_t& transp_addr, asn1::fixed_octstring<4, true>& gtpu_teid_id);
// args
s1ap* s1ap_ptr;
srslog::basic_logger& logger;
// state
bool release_requested = false;
srsran::unique_timer ts1_reloc_prep; ///< TS1_{RELOCprep} - max time for HO preparation
srsran::unique_timer ts1_reloc_overall; ///< TS1_{RELOCOverall}
srsran::unique_timer overall_procedure_timeout;
// Procedure state
s1ap_proc_id_t current_state = s1ap_proc_id_t::nulltype;
erab_id_list updated_erabs;
srsran::bounded_vector<asn1::s1ap::erab_item_s, ASN1_S1AP_MAXNOOF_ERABS> failed_cfg_erabs;
public:
// user procedures
srsran::proc_t<ho_prep_proc_t> ho_prep_proc;
};
class user_list
{
public:
using value_type = std::unique_ptr<ue>;
using iterator = std::unordered_map<uint32_t, value_type>::iterator;
using const_iterator = std::unordered_map<uint32_t, value_type>::const_iterator;
using pair_type = std::unordered_map<uint32_t, value_type>::value_type;
ue* find_ue_rnti(uint16_t rnti);
ue* find_ue_enbid(uint32_t enbid);
ue* find_ue_mmeid(uint32_t mmeid);
ue* add_user(value_type user);
void erase(ue* ue_ptr);
iterator begin() { return users.begin(); }
iterator end() { return users.end(); }
const_iterator cbegin() const { return users.begin(); }
const_iterator cend() const { return users.end(); }
size_t size() const { return users.size(); }
private:
std::unordered_map<uint32_t, std::unique_ptr<ue> > users; // maps ENB_S1AP_ID to user
};
user_list users;
// procedures
class s1_setup_proc_t
{
public:
struct s1setupresult {
bool success = false;
enum class cause_t { timeout, failure } cause;
};
struct s1connectresult {
bool success = false;
};
explicit s1_setup_proc_t(s1ap* s1ap_) : s1ap_ptr(s1ap_) {}
srsran::proc_outcome_t init();
srsran::proc_outcome_t step() { return srsran::proc_outcome_t::yield; }
srsran::proc_outcome_t react(const s1connectresult& event);
srsran::proc_outcome_t react(const s1setupresult& event);
void then(const srsran::proc_state_t& result);
const char* name() const { return "MME Connection"; }
uint16_t connect_count = 0;
private:
srsran::proc_outcome_t start_mme_connection();
s1ap* s1ap_ptr = nullptr;
};
ue* handle_s1apmsg_ue_id(uint32_t enb_id, uint32_t mme_id);
std::string get_cause(const asn1::s1ap::cause_c& c);
void log_s1ap_msg(const asn1::s1ap::s1ap_pdu_c& msg, srsran::const_span<uint8_t> sdu, bool is_rx);
srsran::proc_t<s1_setup_proc_t> s1setup_proc;
};
} // namespace srsenb
#endif // SRSENB_S1AP_H