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/**
* 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 SRSEPC_NAS_H
#define SRSEPC_NAS_H
#include "srsran/asn1/gtpc_ies.h"
#include "srsran/asn1/liblte_mme.h"
#include "srsran/common/buffer_pool.h"
#include "srsran/common/security.h"
#include "srsran/interfaces/epc_interfaces.h"
#include "srsran/srslog/srslog.h"
#include <netinet/sctp.h>
namespace srsepc {
static const uint8_t MAX_ERABS_PER_UE = 16;
// MME EMM states (3GPP 24.301 v10.0.0, section 5.1.3.4)
typedef enum {
EMM_STATE_DEREGISTERED = 0,
EMM_STATE_COMMON_PROCEDURE_INITIATED,
EMM_STATE_REGISTERED,
EMM_STATE_DEREGISTERED_INITIATED,
EMM_STATE_N_ITEMS,
} emm_state_t;
static const char emm_state_text[EMM_STATE_N_ITEMS][100] = {"DEREGISTERED",
"COMMON PROCEDURE INITIATED",
"REGISTERED",
"DEREGISTERED INITIATED"};
// MME ECM states (3GPP 23.401 v10.0.0, section 4.6.3)
typedef enum {
ECM_STATE_IDLE = 0,
ECM_STATE_CONNECTED,
ECM_STATE_N_ITEMS,
} ecm_state_t;
static const char ecm_state_text[ECM_STATE_N_ITEMS][100] = {"IDLE", "CONNECTED"};
/*
// MME ESM states (3GPP 23.401 v10.0.0, section 4.6.3)
typedef enum {
ESM_BEARER_CONTEXT_INACTIVE = 0,
ESM_BEARER_CONTEXT_ACTIVE_PENDING,
ESM_BEARER_CONTEXT_ACTIVE,
ESM_BEARER_CONTEXT_INACTIVE_PENDING,
ESM_BEARER_CONTEXT_MODIFY_PENDING,
ESM_BEARER_PROCEDURE_TRANSACTION_INACTIVE,
ESM_BEARER_PROCEDURE_TRANSACTION_PENDING,
ESM_STATE_N_ITEMS,
} esm_state_t;
static const char esm_state_text[ESM_STATE_N_ITEMS][100] = {"CONTEXT INACTIVE",
"CONTEXT ACTIVE PENDING",
"CONTEXT ACTIVE",
"CONTEXT_INACTIVE_PENDING",
"CONTEXT_MODIFY_PENDING",
"PROCEDURE_TRANSACTION_INACTIVE"
"PROCEDURE_TRANSACTION_PENDING"};
*/
typedef enum { ERAB_DEACTIVATED, ERAB_CTX_REQUESTED, ERAB_CTX_SETUP, ERAB_ACTIVE } esm_state_t;
/*
* EMM, ECM, ESM and EPS Security context definitions
*/
typedef struct {
uint64_t imsi;
emm_state_t state;
uint8_t procedure_transaction_id;
uint8_t attach_type;
struct in_addr ue_ip;
srsran::gtpc_f_teid_ie sgw_ctrl_fteid;
} emm_ctx_t;
typedef struct {
ecm_state_t state;
uint32_t enb_ue_s1ap_id;
uint32_t mme_ue_s1ap_id;
struct sctp_sndrcvinfo enb_sri;
bool eit;
} ecm_ctx_t;
typedef struct {
uint8_t erab_id;
esm_state_t state;
uint8_t qci;
srsran::gtpc_f_teid_ie enb_fteid;
srsran::gtpc_f_teid_ie sgw_s1u_fteid;
srsran::gtpc_pdn_address_allocation_ie pdn_addr_alloc;
} esm_ctx_t;
typedef struct {
uint8_t eksi;
uint8_t k_asme[32];
uint8_t autn[16];
uint8_t rand[16];
uint8_t xres[16]; // minimum 6, maximum 16
uint32_t dl_nas_count;
uint32_t ul_nas_count;
srsran::CIPHERING_ALGORITHM_ID_ENUM cipher_algo;
srsran::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;
uint8_t k_nas_enc[32];
uint8_t k_nas_int[32];
uint8_t k_enb[32];
LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT ue_network_cap;
bool ms_network_cap_present;
LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT ms_network_cap;
LIBLTE_MME_EPS_MOBILE_ID_GUTI_STRUCT guti;
} sec_ctx_t;
/*
* NAS Initialization Arguments
*/
typedef struct {
uint16_t mcc;
uint16_t mnc;
uint8_t mme_code;
uint16_t mme_group;
uint16_t tac;
uint16_t paging_timer;
std::string apn;
std::string dns;
std::string full_net_name;
std::string short_net_name;
srsran::CIPHERING_ALGORITHM_ID_ENUM cipher_algo;
srsran::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;
bool request_imeisv;
} nas_init_t;
typedef struct {
s1ap_interface_nas* s1ap;
gtpc_interface_nas* gtpc;
hss_interface_nas* hss;
mme_interface_nas* mme;
} nas_if_t;
class nas
{
public:
nas(const nas_init_t& args, const nas_if_t& itf);
void reset();
/***********************
* Initial UE messages *
***********************/
// Attach request messages
static bool handle_attach_request(uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
srsran::byte_buffer_t* nas_rx,
const nas_init_t& args,
const nas_if_t& itf);
static bool handle_imsi_attach_request_unknown_ue(uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT& attach_req,
const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT& pdn_con_req,
const nas_init_t& args,
const nas_if_t& itf);
static bool handle_imsi_attach_request_known_ue(nas* nas_ctx,
uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT& attach_req,
const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT& pdn_con_req,
srsran::byte_buffer_t* nas_rx,
const nas_init_t& args,
const nas_if_t& itf);
static bool handle_guti_attach_request_unknown_ue(uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT& attach_req,
const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT& pdn_con_req,
const nas_init_t& args,
const nas_if_t& itf);
static bool handle_guti_attach_request_known_ue(nas* nas_ctx,
uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT& attach_req,
const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT& pdn_con_req,
srsran::byte_buffer_t* nas_rx,
const nas_init_t& args,
const nas_if_t& itf);
// Service request messages
static bool handle_service_request(uint32_t m_tmsi,
uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
srsran::byte_buffer_t* nas_rx,
const nas_init_t& args,
const nas_if_t& itf);
// Dettach request messages
static bool handle_detach_request(uint32_t m_tmsi,
uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
srsran::byte_buffer_t* nas_rx,
const nas_init_t& args,
const nas_if_t& itf);
// Tracking area update request messages
static bool handle_tracking_area_update_request(uint32_t m_tmsi,
uint32_t enb_ue_s1ap_id,
struct sctp_sndrcvinfo* enb_sri,
srsran::byte_buffer_t* nas_rx,
const nas_init_t& args,
const nas_if_t& itf);
/* Uplink NAS messages handling */
bool handle_attach_request(srsran::byte_buffer_t* nas_rx);
bool handle_pdn_connectivity_request(srsran::byte_buffer_t* nas_rx);
bool handle_authentication_response(srsran::byte_buffer_t* nas_rx);
bool handle_security_mode_complete(srsran::byte_buffer_t* nas_rx);
bool handle_attach_complete(srsran::byte_buffer_t* nas_rx);
bool handle_esm_information_response(srsran::byte_buffer_t* nas_rx);
bool handle_identity_response(srsran::byte_buffer_t* nas_rx);
bool handle_tracking_area_update_request(srsran::byte_buffer_t* nas_rx);
bool handle_authentication_failure(srsran::byte_buffer_t* nas_rx);
bool handle_detach_request(srsran::byte_buffer_t* nas_rx);
/* Downlink NAS messages packing */
bool pack_authentication_request(srsran::byte_buffer_t* nas_buffer);
bool pack_authentication_reject(srsran::byte_buffer_t* nas_buffer);
bool pack_security_mode_command(srsran::byte_buffer_t* nas_buffer);
bool pack_esm_information_request(srsran::byte_buffer_t* nas_buffer);
bool pack_identity_request(srsran::byte_buffer_t* nas_buffer);
bool pack_emm_information(srsran::byte_buffer_t* nas_buffer);
bool pack_service_reject(srsran::byte_buffer_t* nas_buffer, uint8_t emm_cause);
bool pack_tracking_area_update_reject(srsran::byte_buffer_t* nas_buffer, uint8_t emm_cause);
bool pack_attach_accept(srsran::byte_buffer_t* nas_buffer);
/* Security functions */
bool integrity_check(srsran::byte_buffer_t* pdu, bool warn_failure = true);
bool short_integrity_check(srsran::byte_buffer_t* pdu);
void integrity_generate(srsran::byte_buffer_t* pdu, uint8_t* mac);
void cipher_decrypt(srsran::byte_buffer_t* pdu);
void cipher_encrypt(srsran::byte_buffer_t* pdu);
/*Timer functions*/
bool start_timer(enum nas_timer_type type);
bool expire_timer(enum nas_timer_type type);
/* UE Context */
emm_ctx_t m_emm_ctx = {};
ecm_ctx_t m_ecm_ctx = {};
esm_ctx_t m_esm_ctx[MAX_ERABS_PER_UE] = {};
sec_ctx_t m_sec_ctx = {};
private:
srslog::basic_logger& m_logger = srslog::fetch_basic_logger("NAS");
gtpc_interface_nas* m_gtpc = nullptr;
s1ap_interface_nas* m_s1ap = nullptr;
hss_interface_nas* m_hss = nullptr;
mme_interface_nas* m_mme = nullptr;
uint16_t m_mcc = 0;
uint16_t m_mnc = 0;
uint16_t m_mme_group = 0;
uint16_t m_mme_code = 0;
uint16_t m_tac = 0;
std::string m_apn;
std::string m_dns;
std::string m_full_net_name;
std::string m_short_net_name;
bool m_request_imeisv = false;
// Timers timeout values
uint16_t m_t3413 = 0;
// Timer functions
bool start_t3413();
bool expire_t3413();
};
} // namespace srsepc
#endif // SRSEPC_NAS_H